Immune checkpoint inhibitors (ICIs) deliver prominent anti-tumor efficacy across multiple malignancies, yet ICI-associated myocarditis represents a life-threatening adverse event requiring standardized management. Updated from the 2022 version, these recommendations integrate up-to-date domestic and international real-world data and emerging evidence concerning bispecific antibody-related cardiac injury, thymic imaging grading, artificial intelligence-assisted early screening, and optimized second-line immunosuppressive regimens. These recommendations provide standardized practical guidance for prevention, early recognition and individualized intervention to improve patient outcomes.

Background and Objectives: Proteasomes formed by a 20S proteasome capped by the 19S regulatory particle at one (26S) or both ends (30S) are responsible for the proteolytic step of the ubiquitin-proteasome system-mediated targeted degradation of most cellular proteins. Proteasome dysfunction is associated with a wide range of age-related diseases, including cardiac diseases. However, age-related changes in myocardial proteasome abundance, activity, and catalytic efficiency, as well as their sex-dependence are understudied. This study was conducted to systematically characterize changes in cardiac proteasome abundance and function across the lifespan of two commonly used mouse strains. Hypothesis: We hypothesized that aging reduces the abundance and/or catalytic efficiency of myocardial proteasomes. Methods: Crude protein extracts from ventricular myocardium of male (n=4, 4, 3) and female (n=4, 5, 3) FVB/N mice, and male (n=4, 4, 5) and female (n=5, 4, 4) C57BL/6J mice at 4-, 12-, and 24-month of age were subjected to native gel electrophoresis. In-gel chymotrypsin-like activity assays followed by Western blot analyses for the β5 subunit (Psmb5) of the 20S proteasome and Rpt2 of the 19S cap were performed, which allows quantification of the abundance and activities of 30S and 26S proteasomes and the abundance of 20S proteasomes in the same gel. Two-way (age, sex) ANOVA followed by Tukey’s post hoc tests were adopted for statistical comparisons. Results: Age-related but sex-independent increases in 20S and 30S abundance were detected in both FVB/N (p=0.002, 0.046) and C57BL/6J (p=0.002, 0.010) mice. In FVB/N mice, the 30S activity exhibited age- and sex-dependent variations (p=0.012, 0.027), but abundance-corrected 30S activity showed an age-dependent decline (p=0.005) without sex difference (p=0.162); 26S abundance was unaffected by age (p=0.587), but its activity showed an age-dependent decline (p=0.001), resulting in age-dependent decreases in abundance-corrected 26S activities (p=0.059). In C57BL/6J mice, 30S activity exhibited sex-dependent variation (p=0.007) without significant impact from age (p=0.341), but abundance-corrected 30S activity showed age dependence (p=0.0387) with no sex difference (p=0.8832); 26S abundance and activity were not affected by age (p=0.123, 0.189) but abundance-corrected 26S activity displayed age-dependent declines (p=0.015). No sex differences were observed in any 26S parameters in FVB/N or C57BL/6J mice. Conclusions: Aging increases myocardial proteasome abundance in FVB/N and C57BL/6J mice, but this is accompanied by a reduced catalytic efficiency in both sexes. It will be important to test whether this occurs in other organs and elucidate the mechanism underlying this age-related decline. Funding Sources: NIH grants R01AG072510, R01HL072166, and R01HL153614 (to X. Wang). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Aims Vascular smooth muscle cell (VSMC) phenotypic remodelling is pivotal to neointimal hyperplasia (NH), a common pathological response to vascular injury. COPS5/CSN5/JAB1 harbours the deneddylase of the COP9 signalosome (CSN) holocomplex but also has deneddylation-independent function. The role of COPS5 in VSMCs remains obscure.Methods and results COPS5/CSN5 was increased in human idiopathic pulmonary hypertension neointima and atherosclerotic lesions and rabbit vein grafts. Smooth muscle-restricted COPS5 knockout (COPS5-SMKO) markedly inhibited left common carotid artery ligation-induced VSMC dedifferentiation, proliferation, and NH in mice. However, COPS8 hypomorphism (COPS8-hypo) exhibiting increased COPS5/CSN5 mini-complexes and enhanced nuclear export of TP53/p53 and CDKN1B/p27 displayed significantly exacerbated NH and VSMC dedifferentiation and proliferation in vivo and in cellulo. Inhibiting COPS5 nuclear export either pharmacologically or genetically suppressed the enhanced dedifferentiation and hyperproliferation and restored nuclear TP53/p53 and CDKN1B/p27 in COPS8 hypomorphic VSMCs. Interestingly, inhibition of COPS5 deneddylase activity had no such effect on VSMC phenotypic modulation but significantly suppressed proliferation, highlighting distinct roles of COPS5 nuclear export and deneddylase functions. Moreover, overexpressing wild-type COPS5 selectively increased COPS5/CSN5 mini-complexes, further promoted nuclear export of TP53/p53 and PDGF-BB induced increases in nuclear KLF4 and VSMC dedifferentiation and proliferation.Conclusion Vessel injury up-regulates vascular COPS5/CSN5. Nuclear export driven by the increased COPS5/CSN5 mini-complexes in VSMCs mediates and promotes VSMC dedifferentiation and phenotypic modulation, whereas the CSN deneddylase activity is not required for VSMC dedifferentiation but is crucial for VSMC proliferation during NH.

Immune checkpoint inhibitors (ICIs) have prolonged cancer survival but exacerbated atherosclerotic cardiovascular disease (ASCVD). This research aims to interrogate the underlying mechanism of ICIs-related atherosclerotic progression and the potential protective effect of Red Yeast Rice (RYR) on it. A tumor-bearing atherosclerotic (TB-AS) mouse model was established by subcutaneously injecting MC38 cells in male ApoE-/- mice fed a high-fat diet (HFD). Intraperitoneal anti-PD-1 antibody (αPD-1) with/without dietary RYR supplementation was administered during the model. Serum was separated for lipid and inflammation evaluation. Plaque assessment was quantified by histological staining. Bone marrow-derived macrophages (BMDMs) were isolated, incubated in growth medium containing 5% serum from the mice model, and treated with ox-LDL and RYR. Cell viability was accessed by CCK8 assay. Lipid staining was employed to assess lipid droplet accumulation. The apoptosis and polarization of BMDMs were analyzed using flow cytometry. Cytokine levels were determined by luminex multiplex assay. And finally, western blot was conducted for mechanism investigation. αPD-1 significantly increased atherosclerotic lesion area, plaque lipid content, and macrophage/T-cell infiltration versus untreated TB-AS controls. These effects coincided with elevated pro-inflammatory cytokines/chemokines and reduced anti-inflammatory mediators. RYR co-treatment attenuated these αPD-1-induced pro-atherogenic changes. In vitro, compared with serum from TB-AS mice, BMDMs cultured with serum from αPD-1-treated TB-AS mice exhibited reduced cell viability, elevated pro-inflammatory cytokine levels in culture supernatants, enhanced M1 polarization, and increased apoptosis levels. All these phenotypic changes were reversed by RYR treatment. Mechanistically, RYR significantly inhibited the RhoA-mediated activation of NF-κB and MAPK signaling, thereby suppressing the αPD-1-induced inflammatory response in BMDMs. αPD-1 promotes ASCVD progression by enhancing macrophage inflammation and T-cell recruitment within plaques. RYR mitigates these effects through RhoA inhibition, suggesting its therapeutic potential for improving cardiovascular outcomes in ICIs-treated cancer patients with ASCVD.

Heart failure (HF) is primarily driven by ischemic heart disease (IHD), including myocardial infarction (MI). Phosphorylation of RPN6 at Ser14 (pS14-RPN6) by the cAMP-dependent kinase (PKA) enhances proteasomes, but its pathophysiological importance in IHD remains unclear. This study tests the hypothesis that proteasome activation via pS14-RPN6 protects against myocardial ischemic injury and post-MI cardiac remodeling and HF. Genetic blockade of the activation of 26S proteasomes by PKA in Rpn6S14A/S14A knock-in (S14A) mice was previously validated. MI was surgically induced in wild-type (WT) and S14A mice. Myocardial pS14-Rpn6 and ubiquitinated protein levels were measured by western blots. Serial echocardiography was performed before and after (every two weeks for 12 weeks) surgery. Post-MI survival was compared between genotypes during acute and chronic phases. Left ventricular (LV) cavity volume was measured at terminal experiments. Following acute MI, pS14-Rpn6 was significantly increased in WT mice (3.58±0.56-fold vs. sham, p< 0.05). Compared to WT MI, S14A MI showed higher levels of total ubiquitinated (1.20±0.13 vs. 1.57±0.25-fold, p< 0.05) and K48-linked ubiquitinated proteins (1.31±0.14 vs. 1.53±0.21-fold, p< 0.05), indicating impaired proteasome function. In chronic post-MI hearts, S14A MI exhibited persistently higher total ubiquitinated (1.29±0.04 vs. 1.64±0.07-fold, p< 0.05) and K48-linked ubiquitinated proteins (1.32±0.07 vs. 1.64±0.11-fold, p< 0.05) versus WT MI, confirming sustained proteasome dysfunction. From 4 to 12 weeks post-MI, echocardiography revealed a progressive decline in systolic function in S14A mice compared with WT mice, as reflected by greater reductions in ejection fraction (EF) and fractional shortening (FS), and more progressive chamber dilatation in S14A MI vs. WT MI. At 12-week endpoint, S14A MI mice showed more decreases in EF (18.34±1.61% vs. 11.49±1.30%, p< 0.0001) and FS (8.40±1.19% vs. 5.22±0.59%, p< 0.0001), along with more increases in LV end-diastolic volume (152.0±25.06 vs. 214.0±34.31, p< 0.0001), and LV mass to body weight ratio (5.82±0.85 vs. 7.64±1.04, p< 0.0001). LV cavity volume was significantly larger in S14A MI hearts compared with WT MI at 12 weeks (46.60±1.60 vs. 55.60±2.42, p< 0.01). Acute post-MI survival did not differ between genotypes, but chronic survival was reduced in S14A MI mice (p< 0.05). These findings demonstrate that pS14-RPN6 is essential for myocardial proteostasis and protects against post-MI cardiac remodeling, indicating proteasome activation by PKA as a key cardioprotective mechanism and potential therapeutic strategy for IHD. Funding: This study is supported by NIH R01 grants (R01 HL072166-18, R01 HL153614-05, R01 AG072510-02). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background: Vascular smooth muscle cell (VSMC) phenotypic remodeling is pivotal to neointimal hyperplasia (NH), a common pathological response to vascular injury and a known complication of vascular procedures. CSN5/JAB1 is an essential catalytic component of the COP9 signalosome (CSN) responsible for deneddylation of cullin-RING ligases, a key regulatory mechanism maintaining cellular protein homeostasis. CSN5i-3, a novel chemical inhibitor of CSN deneddylase has previously demonstrated potent antiproliferative effects in cancer, yet its relevance to vascular pathology remains unexplored. Here, we investigated whether targeted pharmacological inhibition of CSN deneddylase function using CSN5i-3 could influence NH following arterial injury. Methods and Results: Wild-type mice were treated with CSN5i-3 (20 mg/kg/day, i.p.) or vehicle and subjected to left common carotid artery (LCCA) ligation. Ligated and control (right common carotid artery, RCCA) arteries were excised on the 7th day of treatment and assessed for pharmacodynamic markers, the effect on VSMC phenotypic modulation, and neointima formation. CSN5i-3 treatment regime did not affect mouse body weight but, consistent with selective deneddylase inhibition, CSN5i-3 treated arteries exhibited increased neddylated Cullin1 and decreased Skp2 protein levels. Interestingly, the treatment did not alter the ligation-induced changes in the mRNA levels of MYOCD, KLF4 or SMC differentiation markers in vessel wall, suggesting that VSMC dedifferentiation into a synthetic state proceeds independently of CSN deneddylase activity. However, CSN5i-3 markedly attenuated the ligation-induced increases in COL1A1, FN1, CCND1, and CCND2, genes associated with extracellular matrix deposition and cell-cycle progression. Moreover, CSN5i-3 significantly repressed the proliferative response to vascular injury. Ligation-induced PCNA upregulation was significantly suppressed in CSN5i-3 treated mice; and dual Ki67/SM22α immunostaining demonstrated a pronounced reduction in VSMC proliferation accompanied by markedly attenuated NH in CSN5i-3 treated mice, indicating a protective effect of CSN deneddylase inhibition on arterial remodeling following injury. Conclusion: Collectively, these findings demonstrate that CSN deneddylase activity is not required for mature VSMC dedifferentiation into synthetic VSMCs but promotes the proliferation of dedifferentiated VSMCs, which suggests the dedifferentiation and proliferation of VSMCs in response to injury are separatable processes. Pharmacological targeting of CSN deneddylase activity with CSN5i-3 effectively suppresses NH, highlighting the CSN as a promising therapeutic target for limiting restenosis and other occlusive vascular diseases. Funding Source: NIH grants HL085629, HL072166, and HL153614 (to X.W.). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Immune checkpoint molecules (ICMs) are a class of surface proteins predominantly expressed on immune cells that play a key role in maintaining immune homeostasis by regulating the functions of T cells and other immune cells. Beyond their established immunoregulatory roles, emerging evidence indicates that ICMs are also involved in metabolic regulation. Within the tumor microenvironment (TME), tumour-derived ICMs have been shown to modulate glucose, amino acid, and lipid metabolism in infiltrating T cells, thereby influencing their metabolic reprogramming and functional states. Certain ICMs expressed on immune cells may directly regulate systemic metabolism through cell-intrinsic, immune-independent mechanisms. Moreover, specific ICMs are constitutively expressed in key metabolic tissues, such as pancreatic islets, liver, and adipose tissue, where they are thought to contribute to the maintenance of systemic metabolic homeostasis. Clinically, host metabolic status can affect the efficacy of immune checkpoint inhibitor (ICI) therapies. Conversely, ICI treatment can lead to metabolism-related adverse effects, such as ICI-associated diabetes (ICI-DM), which may extend beyond classic autoimmune insulin-dependent diabetes. Accumulating evidence suggests that ICMs can exert direct regulatory roles in metabolism independent of their canonical immune functions. Elucidating how ICMs regulate metabolism could, on the one hand, improve ICI therapy by maintaining metabolic homeostasis and preventing T cell exhaustion, and on the other hand, facilitate the development of novel therapeutic strategies for metabolic diseases that simultaneously target metabolic and inflammatory pathways. This review synthesises current knowledge on the metabolic roles and regulatory mechanisms of ICMs.

BackgroundSustained but decoyed activation of JAK1-STAT pathway occurs in mouse and cell models of increased proteotoxic stress and may exacerbate proteotoxicity. However, the pathogenic mechanisms of this decoyed pathway remain to be explored.ObjectivesDetermining the contribution of JAK1-STAT pathway decoy to cardiac proteotoxicity in mice.MethodsMice with cardiomyocyte-restricted Jak1 deletion (Jak1-cko) were crossbred into the transgenic CryABR120G (R120G) based mouse model of cardiac proteinopathy. Jak1 inhibitor itacitinib and p38 MAPK inhibitor SB203580 were administrated via osmotic minipumps (2.4mg/kg/day×28 days) or daily intraperitoneal injections (10mg/kg/day×21 days). Mouse cardiac function and morphometry were assessed with serial echocardiography, and biochemical markers of myocardial proteostasis and pathology were assessed at terminal experiments. Kaplan-Meier survival was also monitored.ResultsJak1-cko mice developed late-onset dilated cardiomyopathy at baseline. Jak1-cko alleviated the increases in myocardial insoluble p-STAT1 and STAT1, total ubiquitin conjugates, and NPPB proteins in R120G mice at 3-months-of-age but exerted stage-dependent effects on disease progression. Itacitinib attenuated increases in myocardial insoluble p-STAT1 and STAT1, ubiquitin conjugates, and ameliorated diastolic malfunction in R120G mice. SB203580 attenuated the accumulation of insoluble p-STAT1 and misfolded proteins in cultured CMs expressing R120G and protected against diastolic malfunction in R120G mice.ConclusionsJAK1 and p38 MAPK kinases are required for aberrant protein aggregation to decoy STAT1; both loss of canonical JAK1-mediated signaling and disruption of proteostasis contribute to the pathogenesis of the decoyed activation of JAK-STAT pathway, suggesting the JAK1-p38 MAPK-STAT1 axis as a potential therapeutic target for disease with increased proteotoxic stress.

Background: The JAK- STAT pathway is a major signal transduction pathway mediating the signaling of extra cellular cytokines that regulate crucial cellular processes. Prominent activation of JAK-STAT signaling in heart diseases highlights its essential role in cardiac physiology and pathology. Although JAK1 is the predominant JAK in cardiomyocytes (CMs), its physiological significance remains unclear. The objective of this study is to define the role of CM JAK1 in cardiac homeostasis and function, with the hypothesis that CM JAK1 is indispensable for maintaining normal cardiac function. Methods: CM-restricted Jak1 deletion (Jak1-cko) was achieved by crossbreeding the Jak1flox/flox mice with transgenic mice overexpressing the Cre recombinase driven by the mouse alpha-myosin heavy chain promoter (Myh6-Cre). Jak1-cko was verified in Jak1flox/flox::Myh6-Cre mice at both gene and protein levels. Cardiac morphometry and function were determined by serial echocardiography (Echo). Results: Western blot analyses showed that Jak1-cko mice showed decreases in myocardial JAK1 (0.56±0.15 vs. 1.00±0.13, p=0.0001), and downstream Tyr705-phosphorylated STAT3 (0.51±0.17 vs. 1.00±0.47, p=0.0623) and total STAT3 (0.51±0.15 vs. 1.00±0.18, p=0.0004) proteins, compared to Myh6-Cre control mice. M-mode Echo has revealed that Jak1-cko mice develop dilated cardiomyopathy and this phenotype is evident at 4.5 months in males and at 6 months in females. Male Jak1-cko mice had decreased ejection fraction compared to male Myh6-Cre control (31.12±6.90 % vs. 36.41±6.61 %, p=0.0493), while females showed no significant difference at 6m of age, which is consistent with a sex-difference in changes of left ventricular (LV) chamber dilatation at 6m of age. In males, Jak1-cko significantly increased LV end-systolic diameter (4.51±0.60 mm vs. 3.99±0.53 mm, p=0.0065) and end-diastolic diameter (5.28±0.54 mm vs. 4.83±0.51 mm, p=0.0116) compared to Myh6-Cre control, whereas female Jak1-cko mice only showed sightly increased LV end-diastolic diameter (4.78±0.28 mm vs. 4.52±0.36mm, p=0.0208) at 6m of age. Kaplan-Meier survival analyses have shown shortened lifespan in Jak1-cko mice compared to Myh6-Cre control (median survival: 242 days vs. 304 days, p< 0.0001). And female Jak1-cko mice survive longer than males (median survival: 256 days vs. 232.5 days, p=0.0254). Conclusions: CM-restricted Jak1 deletion causes dilated cardiomyopathy, heart failure, and premature death in mice, with a more severe phenotype in males than females. These findings suggest that JAK1 is indispensable for maintaining adult heart function Funding sources: American Heart Association (AHA) grant (20TPA35490091), AHA Predoctoral Fellowship (23PRE1023108) This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Heart failure (HF) resulting from chronic systolic overload is associated with increased burden on proteostasis and impaired proteasome function. Phosphorylation of proteasome subunit RPN6/PSMD11 at Ser14 (pS14-RPN6) mediates the activation of 26S proteasomes by PKA, but its significance in common forms of heart disease remains obscure. Hence, we investigated the impact of genetic blockade of pS14-RPN6 on cardiac remodeling and HF during systolic overload, a common condition occurring in hypertension and aortic stenosis. We detected marked increases in ubiquitin conjugates, along with elevated levels of RPN6 and pS14-RPN6 proteins in myocardial tissues from human patients with nonischemic HF. Similarly, myocardial pS14-Rpn6 was increased in wild-type mice 2 and 4 weeks after transverse aortic constriction (TAC). Compared with wild-type littermates, mice with genetic blockade of pS14-Rpn6 resulting from germline knock-in of Rpn6S14A (S14A mice) developed greater cardiac hypertrophy, fibrosis, left ventricular dysfunction, and lung congestion after TAC. Mechanistically, TAC induced comparable increases in 26S and 30S proteasomes at 2-week in both genotypes but, at 4-week post-TAC, the increases were remarkably attenuated in S14A mice. Meanwhile, TAC-induced increases in proteasome peptidase activities were significantly attenuated (2-week) or abolished (4-week) in S14A mice, accompanied by greater increases in total and K48-linked ubiquitin conjugates. Collectively, these findings demonstrate that pS14-RPN6 plays an essential role in upregulating myocardial proteasome activities and sustained upregulation of proteasome assembly, thereby assisting in maintaining proteostasis and protecting against maladaptive cardiac remodeling and HF during systolic overload.

Objective: Heart failure (HF) resulting from chronic systolic overload is characterized by increased proteotoxic stress (IPTS) and impaired ubiquitin proteasome system (UPS) function. The UPS is the main pathway for intracellular proteolysis. Recent evidence challenges the notion that substrate ubiquitination is the only rate-limiting step in UPS-mediated degradation and shows that proteasomal substrate cleavage can also be rate-limiting. Phosphorylation of the 19S proteasome (Psm) subunit RPN6 at Ser14 (pS14-RPN6) is the primary mechanism for PKA to activate the 26S Psm and can attenuate cardiac proteinopathy. However, its role in systolic overload remains unknown; so, this study was conducted to fill this gap. Hypothesis: We hypothesize that pS14-RPN6 is essential for maintaining proteostasis and protects the heart under systolic overload. Methods: Wild type (WT) and Rnp6S14A knock-in (S14A) mice underwent transverse aortic constriction (TAC), and cardiac remodeling was assessed by echocardiography, gravimetry, histology, and biochemical analyses. Proteostasis was examined by quantifying myocardial pS14-Rpn6, Psm abundance and peptidase activity, and total and K48-linked ubiquitin (Ub) conjugates. Human left-ventricular (LV) tissues from non-ischemic HF (NI-HF) patients and non-failing donors were also analyzed. Results: NI-HF myocardium showed increases in total RPN6 (p=0.021), pS14-RPN6 (p=0.019), total Ub-conjugates (p=0.004) and K48-linked Ub-conjugates (p=0.008), indicating IPTS with likely compensatory upregulation of pS14-RPN6 in human HF. Myocardial pS14-Rpn6 increased in WT mice 2 and 4 weeks after TAC (p< 0.005). Although showing no baseline difference, S14A mice displayed greater hypertrophy 1 week after TAC, with increased heart weight, LV wall thickness and LV mass (all p< 0.001) and greater expression of Nppa and Nppb (p=0.038, 0.036). Chronically, TAC induced more severe remodeling, including greater cardiomyocyte profile area, heart and ventricular weight to tibial length ratios, and cardiac fibrosis (all p< 0.001) and more severe systolic dysfunction evidenced by reduced ejection fraction and stroke volume (all p< 0.01), and increased lung congestion indicated by higher lung weight to tibia length ratio (p=0.023) in S14A mice compared to WT mice. Mechanistically, TAC-induced robust increases in myocardial 26S and 30S Psm abundance and activities (all p< 0.05) in WT mice but the TAC-induced Psm activation was significantly blunted, although the changes in abundance were less affected, by S14A, which resulted in greater increases in total and K48-linked Ub-conjugates at 2 and 4 weeks after TAC (p< 0.001). These findings demonstrate that loss of pS14-Rpn6 disrupts proteostasis, accelerates maladaptive remodeling, and HF in systolic overload. Conclusion: pS14-RPN6 is required for efficient Psm-mediated clearance of unwanted proteins during systolic overload and upregulation of pS14-RPN6 is likely a compensatory response during HF, suggesting increasing pS14-RPN6 as a potential therapeutic strategy. Acknowledgement: This study is in part supported by NIH R01HL072166, R01HL153614, and RF1AG072510. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Immune checkpoint inhibitors (ICIs) have revolutionized treatment strategies for cancer; however, some fatal cardiovascular immune-related adverse events, such as myocarditis, limit their clinical application. Here, we report a case of ICI-associated autoimmune dilated cardiomyopathy, which has not been previously reported in the literature. A 63-year-old man with hepatic malignancy treated with envafolimab developed heart failure because of envafolimab-induced autoimmune dilated cardiomyopathy. Endomyocardial biopsy revealed a very small amount of lymphocyte infiltration, which was consistent with the manifestations of dilated cardiomyopathy. After the initiation of heart failure therapy according to the 2021 European Society of Cardiology Guidelines for the diagnosis and treatment of acute and chronic heart failure, he was recovering well and discharged. To our knowledge, this is the first case of dilated cardiomyopathy in a patient treated with envafolimab by subcutaneous injection.

BACKGROUND: Desmin-related cardiomyopathy (DRC) is a proteotoxic disorder driven by mutations in DES and related genes such as CRYABR120G (R120G), leading to progressive cardiac dysfunction. While late-stage transcriptomic changes in cardiomyopathy and aging are well studied, early molecular events during postnatal maturation and disease onset remain poorly defined. METHODS AND RESULTS: Through RNA sequencing of mouse ventricular myocardium at multiple time points, we uncovered novel transcriptional changes associated with postnatal cardiac development in non-transgenic mice, as well as early alterations preceding overt pathology in the R120G-based DRC mice. RT-qPCR and western blotting confirmed the kinase SBK2 was downregulated in multiple DRC mouse models, suggesting a conserved role in disease progression. Comparative analysis of our sequencing datasets and an independent RNA-seq dataset, identified a conserved molecular signature involving autophagy and proteasome pathways, notably including the proteasome subunit Psmd5. Profiler enrichment analysis uncovered shared transcription factor binding motifs implicating a previously unrecognized transcriptional regulator in disease progression. CONCLUSIONS: These findings identify Sbk2, Psmd5, Scml4, Snai3, and Foxn4 as novel candidates in DRC pathogenesis. In the non-transgenic heart, data implicate several transcriptional networks governing the shift from cardiac maturation to detrimental aging including AW551984 and a group of zinc finger C2H2 transcription factors (Zfp41, Zfp273, Zfp456, Zfp469, and Zfp820). These genes have not been studied in the context of cardiac maturation hinting at an unexplored cardiac regulatory network. These findings may provide novel mechanistic insights into the transition from postnatal cardiac maturation to detrimental cardiac aging and proteotoxic stress.

Neointimal hyperplasia (NH) is a prominent pathological consequence following vascular injury and is driven in part by aberrant vascular smooth muscle cell (VSMC) proliferation. COP9 signalosome (CSN) subunit 5 (CSN5/JAB1/COPS5) is the deneddylase component of the CSN holocomplex responsible for deneddylation of cullin-RING ligases. Although CSN5/CSN is well studied in cancer biology, the role of CSN5/CSN in NH and vascular biology remains largely unexplored. Here, we investigated whether selective inhibition of CSN deneddylase activity using CSN5i-3 could mitigate neointimal remodeling following arterial injury. Adult mice were subjected to daily intraperitoneal injections of CSN5i-3 (20 mg/kg/day) or vehicle and left common carotid artery ligation. The left and the right common carotid arteries were then assessed for VSMC phenotypic modulation and neointima formation after 7 days of treatment. CSN5i-3 treatment markedly attenuated the ligation-induced changes in the mRNA level of COL1A1, FN1, CCND1, and CCND2, genes associated with extracellular matrix deposition and cell-cycle progression, but did not alter expression changes of canonical smooth muscle differentiation markers (MYOCD, MYH11, and ACTA2) and KLF4 in the ligated vessel. Importantly, CSN5i-3 significantly blunted the increases of proliferating cell nuclear antigen (PCNA) expression and Ki67-positive VSMCs and reduced neointimal areas. These findings demonstrate that CSN deneddylase activity is dispensable for the dedifferentiation of contractile VSMCs into the synthetic state but promotes VSMC proliferation, supporting the concept that the dedifferentiation and proliferation of VSMCs in neointimal formation are separately regulated processes and differentially regulated by different CSN actions. This study also indicates that CSN5i-3 is highly promising in preventing neointimal hyperplasia.NEW & NOTEWORTHY This study provides compelling in vivo evidence that selective inhibition of COP9 signalosome (CSN) deneddylation activity by CSN5i-3 suppresses neointimal hyperplasia through reducing proliferation of vascular smooth muscle cells without impacting their dedifferentiation. This not only identifies CSN5i-3 as a promising agent in preventing neointimal hyperplasia but also supports the new concept that dedifferentiation and proliferation of vascular smooth muscle cells in neointimal formation are separately regulated processes and differentially regulated by CSN-mediated deneddylation.

Hepatocellular carcinoma (HCC) is one of the most common malignancies with poor prognosis. Novel therapeutic strategies for HCC are urgently needed. Ferroptosis, an iron and reactive oxygen species (ROS) dependent regulated cell death, emerges to efficiently abrogate the growth and proliferation of HCC cells. The identification of new ferroptosis inducing agents should provide potential therapeutics for more effective management of HCC. Here we have identified nelfinavir, a human immunodeficiency virus (HIV) protease inhibitor as a novel ferroptosis inducer in HCC cells, Hepa1-6 and HepG2. Mechanistically, the induction of ferroptosis by nelfinavir required its induction of ER stress; suppression of ER stress remarkably attenuated mitochondrial impairment and superoxide production, the autophagic degradation of GPX4, and increases in the labile iron pool associated with the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) axis in nelfinavir-treated HCC cells. In a mouse model of HCC xenografts, nelfinavir treatment significantly suppressed tumor growth, and this effect was more pronounced when nelfinavir and sorafenib were administered together. Collectively, we demonstrate that nelfinavir can induce ferroptosis in an ER stress dependent manner, thereby identifying a new inducer of ferroptosis that can potentially be repurposed to treat HCC.

Long non-coding RNA LINC00467 exerts a significant impact on various cancer types. However, its precise role in non-small-cell lung cancer (NSCLC) is not fully elucidated. Thus, the current study investigated the potential mechanism by which LINC00467 contributes to the progression of NSCLC. RT-qPCR and fluorescence in situ hybridization (FISH) results showed that overexpression of LINC00467 is closely associated with malignant characteristics in NSCLC patients. It promoted NSCLC cell proliferation and metastasis in both cell culture and animal models. Co-immunoprecipitation (Co-IP) and Western blot results indicated that LINC00467 may enhance the proteasome-dependent degradation of PABPC1 by facilitating its interaction with the ubiquitin E3 ligase E4B. Furthermore, LINC00467 was observed to influence the activity of the Wnt/β-catenin signaling pathway, possibly by regulating PABPC1 stability in NSCLC cells. These findings suggest that LINC00467 may contribute to NSCLC progression through a mechanism involving PABPC1, with the potential to modulate the Wnt/β-catenin pathway. This regulatory axis may provide insight into future therapeutic targets for NSCLC.

Background: Intracellular aberrant protein aggregation (APA) is a hallmark of many forms of human disease. No clinical strategies purposely target APA yet. In a recent study, we have discovered that APA hijacks phosphorylated STATs into protein aggregates thereby decoys and sustains JAK1-STAT activation, which in turn exacerbates APA and proteotoxicity, forming a vicious circle. The objective: of the present study is to further explore the therapeutic implications of this discovery in animals. We hypothesize: that JAK1 inhibition breaks the vicious circle, mitigates the decoyed JAK1-STAT activation, thereby protects against APA and proteotoxicity. Methods: We interrogated JAK1in mice with CryAB R120G (R120G)-based cardiac proteinopathy through Myh6-Cre-driven Jak1 knockout (Jak1-cko) or JAK1 kinase inhibition by Itacitinib and assessed the resultant changes in myocardial proteostasis and disease progression. Results: Western blot analyses showed that Jak1-cko significantly decreased myocardial JAK1 (1.00±0.35 vs. 0.58±0.05, p =0.0170), as well as downstream Ser727-phosphorylated (p-STAT1) (1.00±0.23 vs. 0.40±0.11, p =0.0003) and total STAT1 (1.00±0.15 vs. 0.68±0.19, p =0.0126) proteins in R120G mice; Jak1-cko attenuated the increases of p-STAT1 and total STAT1 in both soluble and insoluble protein fractions. Jak1-cko also attenuated the increases of myocardial ubiquitin conjugates (1.00±0.04 vs. 0.80±0.09, p =0.0034), Natriuretic Peptide A (11.27±4.74 vs. 5.95±2.99, p =0.0348) and B (6.44±0.81 vs. 4.63±0.65, p =0.0010) proteins in R120G mice at 3 months of age, demonstrating that JAK1 plays a major role in the R120G-induced impairment of proteostasis and cardiac pathology.M-mode echocardiography showed that concentric cardiac hypertrophy in R120G mice was markedly alleviated by Jak1-cko, as evidenced that the reduction of left ventricular (LV) end-diastolic volume (53.23±10.08 µL vs. 67.68±10.94 µL, p =0.0162) and the increases in LV posterior wall thickness (0.86±0.08 mm vs. 0.73±0.07 mm, p =0.0230) were attenuated by Jak1-cko.Administration of JAK1 kinase inhibitor Itacitinib (2.4mg/kg/day) via subcutaneous osmotic mini pump for 4 weeks also markedly attenuated the accumulation of insoluble STAT1 (14.08±0.43 vs. 10.56±1.25, p =0.0014) and of insoluble CryAB (1.00±0.05 vs. 0.79±0.05, p =0.0052) in R120G mouse myocardium, indicating that JAK1 kinase inhibition can attenuate APA.Overall, these data suggest that suppressing the sustained phosphorylation of STATs via Jak1 knockout or JAK1 kinase inhibition attenuates APA and proteotoxicity in R120G hearts. Conclusions: This study provides compelling in vivo evidence that JAK1 kinase activity is required for the dysregulated JAK1-STAT pathway to exacerbate APA and proteotoxicity, thereby identifying a potentially new strategy to treat APA-dependent diseases. American Heart Association (AHA) grant (20TPA35490091), AHA Predoctoral Fellowship (23PRE1023108). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

ObjectiveTo investigate the improvement effect of Necrostatin-1 (Nec-1) on mouse models with immune checkpoint inhibitor (ICI) -associated myocarditis (ICIAM) and potential mechanism. MethodsTen male BALB/c mice aged 6-8 weeks were selected to construct the ICIAM models. The echocardiography and serum myocardial injury markers were used to assess cardiac function of mice. The levels of inflammatory markers including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were detected by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Hematoxylin-eosin (HE) staining was used to evaluate myocardial inflammation, and Masson staining was used to evaluate myocardial fibrosis. The expressions of myocardial necroptosis proteins including receptor-interacting protein kinase 1 (RIP1), RIP3, mixed lineage kinase domain-like protein (MLKL) and their phosphorylated forms were detected by Western blotting. The spleen lymphocytes were extracted and co-cultured with HL-1 cell line. Cell viability was measured by cell counting kit-8 (CCK-8). The release of reactive oxygen species (ROS) and changes of mitochondrial membrane potential were observed. RIP1, RIP3, MLKL and their phosphorylated forms were determined. The levels of markers of oxidative stress, including malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were measured. ResultsNec-1 significantly improved the cardiac function injury of mice induced by ICI, and inhibited the release of TNF-α and IL-1β in plasma of ICIAM mice (P＜0.001); inhibited expressions of phosphorylated RIP1, RIP3 and MLKL (P＜0.05); decreased MDA activity, and increased SOD and GSH-Px activity (P＜0.001). In HL-1 cells, Nec-1 intervention inhibited the RIP1-RIP3-MLKL pathway (P＜0.05), improved decrease of the cell viability induced by lymphocytes (P＜0.001), decreased ROS release, increased mitochondrial membrane potential, inhibited MDA activity, and increased SOD and GSH-Px activities (P＜0.001). ConclusionsNecroptosis plays an important role in the occurrence and development of ICIAM，but Nec-1 could alleviate the progression of ICIAM by inhibiting necroptosis induced by oxidative stress in cardiomyocytes; RIP1 maybe a new target in treatment of ICIAM.

Alzheimer's disease (AD) patients often display neurobehavioral and cardiac impairments, but the underlying factors remain unclear. Ser14 phosphorylation in RPN6 (p-S14-RPN6) mediates the activation of 26S proteasomes by protein kinase A (PKA). Proteasome priming is implicated in protection by cAMP-PKA against AD, but this remains to be established. Hence, this study was conducted to interrogate homeostatic p-S14-RPN6 in AD. The recently validated Rpn6 S14A knock-in (S14A) mice were crossbred with the PS19 tauopathy mice (RRID: IMSR_JAX:008169). The resultant wild type (WT), PS19, and PS19::S14A littermates were compared. Expedited declines in cognitive and motor functions as indicated respectively by significant decreases in object recognition and discrimination indexes and rotarod time were observed in PS19::S14A mice vs. PS19 mice, which is associated with more pronounced synaptic losses, microglial activation, and gliosis in the hippocampus. Compared with WT and PS19 mice, PS19::S14A mice showed exacerbated cardiac malfunction, cardiac hypertrophic responses and fibrosis, and greater increases of total and hyperphosphorylated tau proteins and ubiquitin conjugates in both hippocampi and hearts. These findings demonstrate that genetic blockade of p-S14-RPN6 exacerbates tauopathy in both the brain and heart, which for the first time establishes that homeostatic p-S14-RPN6 promotes proteostasis and protects against pathogenesis in AD.