Sjögren’s disease (SjD) is a systemic autoimmune disorder marked by lymphocytic infiltration of exocrine glands. To date, its pathogenesis remains incompletely understood. Cathelicidins are a widespread family of host-defense antimicrobial peptides, primarily recognized for their antimicrobial properties, and are now increasingly appreciated for their immunomodulatory functions. However, the role of cathelicidin in the immunopathogenesis of SjD remains unknown. In this study, we investigated the effects of cathelicidin-related antimicrobial peptide (CRAMP) on SjD and the underlying mechanisms. Salivary gland tissues from SjD patients and controls were collected. Two established mouse models of SjD, i.e., the non-obese diabetic (NOD) mice that spontaneously develop SjD-like disease features, and salivary gland protein-induced experimental SjD mice, were used for the studies. Our data showed that salivary gland acinar cells produce cathelicidin, and that production is impaired in both SjD patients and mice compared to the control group. Moreover, CRAMP plays a protective role in SjD, as exogenous CRAMP administration improved the SjD phenotype, whereas CRAMP knockdown exacerbated disease severity. By combining RNA sequencing with pharmacological inhibitors, we demonstrated that CRAMP acts through formyl peptide receptor 2 (FPR2) to inhibit the PI3K/AKT signaling pathway, thereby reducing the autoimmune response in the salivary glands. Furthermore, we identified gut microbiota and its metabolite, propionic acid, as critical regulators of CRAMP expression in salivary gland acinar cells. Treatment with propionic acid or transfer of gut microbiota from a non-autoimmune control strain to SjD mice increased CRAMP levels and alleviated disease severity, highlighting a pivotal gut-salivary gland axis in SjD pathogenesis. Overall, these findings underscore the pivotal role of CRAMP in protecting against SjD and pave the way for future microbiota-based therapies.
Myocardial ischemia/reperfusion (I/R) injury is partially attributed to impaired autophagic clearance and pyroptotic inflammation. This study investigated whether bufalin protects the myocardium by preserving Beclin-1-dependent autophagic flux. In mice subjected to myocardial I/R, bufalin preserved cardiac function, reduced infarct size and myocardial injury, and inhibited NLRP3/GSDMD-associated pyroptotic signaling. In neonatal mouse primary cardiomyocytes exposed to oxygen-glucose deprivation/reoxygenation (OGD/R), bufalin enhanced cell viability, mitigated oxidative stress and pyroptotic signaling, and restored autophagic flux and lysosomal homeostasis, evidenced by increased Beclin-1 and LC3B levels, decreased P62 accumulation, improved tandem mCherry-GFP-LC3 flux, and preserved lysosomal proteins and cathepsin compartmentalization. Similar cellular effects were observed in H9c2 cells. Pharmacological disruption of early autophagosome formation or late autophagosome–lysosome turnover compromised bufalin-mediated protection. Mechanistically, bufalin increased the stability of Beclin-1 protein without elevating its mRNA levels, weakened the RNF216–Beclin-1 association, and reduced K48-linked ubiquitination of Beclin-1. In primary cardiomyocytes, RNF216 overexpression restored Beclin-1 ubiquitination and attenuated bufalin-mediated protection, whereas RNF216 knockdown generated a similar protective profile and limited the additional response to bufalin. Together, these findings identify the RNF216/Beclin-1 axis as a regulator of cardiomyocyte autophagic competence and support bufalin as a potential strategy for limiting pyroptotic injury during myocardial reperfusion.
Mitochondrial antiviral signalling protein (MAVS), also known as interferon-β (IFN-β) promoter stimulator 1 (IPS-1), virus-induced signalling adaptor (VISA), and CARD adaptor inducing IFN-β (CARDIF), has emerged as a regulatory node linking mitochondrial stress, innate immune signalling, and cardiovascular disease (CVD) pathogenesis. In the cardiovascular system, MAVS is activated not only by viral RNA sensors such as retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5), but also by endogenous danger signals. This activation promotes transcription of NLR family pyrin domain-containing 3 (NLRP3) and pro-inflammatory cytokines, and facilitates NLRP3 inflammasome assembly and cytokine maturation, processes implicated in myocardial inflammation, remodelling, and dysfunction in conditions such as myocardial hypertrophy, atherosclerosis, and cardiomyopathy. Beyond inflammasome activation, MAVS intersects with multiple cell death and homeostatic pathways relevant to CVD, including apoptosis, autophagy, and, potentially, ferroptosis. Preclinical studies show that genetic ablation of MAVS, or pharmacological interventions that limit mitochondrial reactive oxygen species (mtROS), mitochondrial double-stranded RNA (mtdsRNA) release, or downstream innate immune signalling, can attenuate MAVS-associated inflammation, oxidative stress, and metabolic remodelling, thereby slowing disease progression in experimental cardiovascular models. MAVS, however, also performs essential protective functions, particularly in antiviral defence and maintenance of cardiac homeostasis, underscoring the need for context-specific, cell-type-restricted, or pathway-selective modulation rather than indiscriminate inhibition. Collectively, these findings position MAVS as a promising therapeutic target in CVD, warranting further investigation into MAVS-associated signalling pathways and their modulation in cardiovascular contexts.
Acetaminophen (APAP) overdose is a leading cause of drug-induced liver injury, driven by oxidative stress and disruption of mitochondrial and lysosomal homeostasis. While transcription factor EB (TFEB) is a known master regulator of autophagy and antioxidant pathways, the upstream mechanism that triggers its activation during APAP hepatotoxicity remains unclear. Here, we demonstrate that the citrus flavonoid hesperetin orchestrates a PKC–TFEB signaling pathway to simultaneously mitigate oxidative damage and restore organelle function in APAP-induced liver injury. Hesperetin enhanced TFEB nuclear translocation and transcriptional activity, thereby restoring autophagic clearance of APAP–protein adducts and mitochondrial biogenesis, as well as SQSTM1/p62-dependent noncanonical NFE2-like bZIP transcription factor 2 (NFE2L2/NRF2) activation to protect against APAP-induced liver injury. Mechanistically, hesperetin directly targeted and activated protein kinase C (PKC), preventing its degradation and thus leading to TFEB activation. Our study identifies hesperetin as a novel small-molecule activator of a PKC–TFEB pathway, which couples NRF2-dependent redox balance with mitochondrial–lysosomal repair to counteract APAP toxicity. These findings propose a new strategy for treating oxidative-stress-driven liver injury by targeting TFEB-mediated homeostasis.
Ferroptosis, a type of regulated cell death characterized by lipid peroxide accumulation, has emerged as a promising subroutine of cell death capable of sensitizing chemoresistant cancer cells. To identify novel ferroptosis inducers, a natural product library of 1023 compounds was screened, leading to the identification of Hdj-15. Hdj-15 elicited oxidative stress, the unfolded protein response (UPR), lysosomal biogenesis, and massive lipid peroxidation to trigger ferroptosis. Mechanistically, Hdj-15 directly targeted TrxR1, leading to oxidative stress and ER stress. Knockdown of TXNRD1 (which encodes TrxR1) further sensitized cells to Hdj-15, and reconstitution with wild-type, but not U498C mutant, TXNRD1 reversed this effect. The IRE1α branch of the UPR was activated upon Hdj-15 treatment, which in turn enabled X-box binding protein 1 (XBP1) to directly transactivate transcription factor E3 (TFE3) and transcription factor EB (TFEB), thereby triggering lysosomal biogenesis. Chromatin immunoprecipitation (ChIP) revealed that XBP1s directly occupied the -735 to -631 and the -493 to -365 sites of the TFE3 and TFEB promoters. Hdj-15-induced lysosomal biogenesis further facilitated lysosomal GPX4 degradation via chaperone-mediated autophagy (CMA), sensitizing cancer cells to ferroptosis. Furthermore, drug-resistant cancer cells (Taxol-resistant A549 cells and gefitinib-resistant PC9 cells), including both p53-proficient and p53-deficient cells, were vulnerable to Hdj-15-mediated GPX4 inhibition. In xenograft tumor models, Hdj-15 suppressed tumor growth in vivo. In summary, elucidating the molecular mechanisms of the novel ferroptosis inducer Hdj-15 demonstrated that the interplay between the ER and lysosomes plays a critical role in shaping ferroptotic cell death, which in turn sensitizes drug-resistant cancer cells.
