BACKGROUND:Although pulmonary arterial hypertension (PAH) is a rare and fatal disease that is well-characterized, vasodilator-responsive PAH accounts for a minority of cases, with little mechanistic knowledge, but with dramatically improved survival. METHODS:By assembling national cohorts, we evaluated genetic influences on acute vasodilator drug response, a key determinant of the presence of vasodilator-responsive PAH. Differences between hemodynamics at rest and after a PAH-specific vasodilator were tested in a genome-wide association study. Validated loci were functionally tested in cell culture and in a hypoxic mouse model of pulmonary hypertension. RESULTS:Rs8057488 in the sorting nexin 29 (SNX29) gene reached genome-wide significance in the discovery cohort (P=4.00×10-8) and was nominally replicated (P=0.027). Consistent with its predicted function, SNX29 demonstrated an endosomal distribution in PA smooth muscle cells. Silencing SNX29 redistributed stromal interaction molecule proteins to the cell membrane and enhanced store-operated calcium entry. Over-expression of SNX29, in vivo, attenuated hypoxic vasoconstriction in isolated perfused murine lung models. CONCLUSIONS:The data cumulatively suggest SNX29 may contribute to vasodilation partly through reduced store-operated calcium entry and endosomal trafficking of store-operated calcium entry proteins, advancing our understanding of vasodilator-responsive PAH.

Endothelial cell (EC) barrier integrity is tightly regulated by the activity of the non-muscle myosin light chain kinase (nmMLCK) under diverse pathological inflammatory conditions (pneumonia, sepsis) and exposure to mechanical stress. Inflammatory stimuli, including lipopolysaccharide (LPS), cytokines, and damage-associated molecular patterns (DAMPs), increase EC permeability through nmMLCK-dependent EC paracellular gap formation. However, the exact mechanisms by which nmMLCK regulates vascular barrier dysfunction in acute lung injury (ALI) remain incompletely understood. We hypothesized that inflammation-induced ROS results in the peroxynitrite-mediated nitration of nmMLCK that contributes to EC barrier disruption. Human lung EC exposure to either the peroxynitrite donor, SIN-1, or to LPS, triggered significant nmMLCK nitration, which was abolished by the oxidant scavenger, MnTMPyP. Mass spectrometry of SIN-1-treated nmMLCK identified multiple nitrated tyrosines. Nitration of Y1410 proved a critical PTM as site-directed substitution with alanine (Y1410A) abolished both SIN-1- and LPS-induced nmMLCK nitration. nmMLCK nitration disrupts wild-type nmMLCK interaction with Kindlin-2, a cytoskeletal regulator of vascular barrier stability, whereas EC transfected with the Y1410A nmMLCK mutant exhibited preserved Kindlin-2 binding, reflected by alterations in trans-EC electrical resistance (TEER). Consistent with these observations, LPS-challenged murine lungs displayed enhanced nmMLCK nitration and diminished nmMLCK-Kindlin-2 association. Functionally, SIN-1 markedly impaired EC barrier integrity (TEER), which was not observed in ECs expressing the Y1410A mutant. Together, these findings suggest that nmMLCK nitration at Y1410 is a critical molecular mechanism contributing to vascular leakage, highlighting this modification as a potential therapeutic target to reduce inflammation-induced vascular permeability. Given nmMLCK’s established role in barrier regulation, we hypothesized that LPS-induced peroxynitrite formation may promote the nitration of nmMLCK tyrosine residues: a PTM that potentially contribute to nmMLCK’s regulation of EC barrier integrity.

ABSTRACT Introduction Pulmonary arterial hypertension (PAH) is characterized by progressive pulmonary vascular remodeling. Pulmonary vascular impedance (PVZ) provides a comprehensive view of pulmonary arterial function. We hypothesized that functional vascular remodeling significantly alters pulsatile pulmonary hemodynamics and PVZ in severe PAH. Methods Participants with a right heart catheterization (RHC) and an echocardiogram including right ventricular outflow tract (RVOT) images (delay: 24 [5–76] days) were identified from the University of Arizona PH registry. Participants were split using the World Symposium PH classifications and PVR (mild: < 3.9WU, Moderate: 3.9–8.5WU and Severe: > 8.5WU). PVZ was calculated in the frequency domain using pulmonary artery (PA) pressure and RVOT‐PA flow profiles. Impedance measures of resistance ( Z 0 ), global stiffness ( Z 1 ) and proximal stiffness ( Z C , average Z 2‐4Hz ) were derived. To evaluate proximal arterial mechanics, we used the Z c‐mPAP relationship to distinguish pressure‐dependent from stiffness‐related changes on Z C . Data were presented as median [interquartile range]. Results Forty‐eight subjects were identified (Control (mPAP < 25 mmHg): n = 8 and WSPH1: n = 40). Z 0 and Z C were significantly increased in WSPH1 compared to Control ( p < 0.05). Z 0 , Z 1 , and Z C were increased in WSPH1‐severe compared WSPH1‐mild and WSPH1‐moderate ( p < 0.05). All impedance parameters correlated with end‐systolic elastance (Ees) and arterial elastance (Ea, p < 0.05) but only Z 0 correlated with Ees/Ea ( p < 0.05). Z C ‐mPAP relationships were modeled for Control and WSPH groups using estimated unstressed diameters (16.7–27.0 mm) and wall thickness/elastic modulus pairs. Conclusion PVZ analysis demonstrates increased resistance ( Z 0 ), global stiffness ( Z 1 ), and proximal stiffness ( Z C ) in severe PAH. The Z C ‐mPAP relationship suggests proximal vascular stiffening.

New biomarkers are needed to detect and follow individuals with World Health Organization group 1.1 pulmonary hypertension (idiopathic pulmonary arterial hypertension (IPAH)). As NOTCH3 cleavage occurs constitutively in the lungs of individuals with IPAH, we investigated whether the NOTCH3 extracellular domain (NOTCH3-ECD) shed into serum could be used as a robust biomarker for IPAH. In three geographically distinct cohorts comprising 341 individuals with IPAH (267 women, 74 men) and 376 healthy individuals (278 women, 98 men), serum NOTCH3-ECD levels were significantly higher in individuals with IPAH (mean ± s.d.: 19.9 ± 5.5 ng ml-1) compared to controls (10.5 ± 1.9 ng ml-1; P < 0.001), with consistent results among the three cohorts. NOTCH3-ECD levels correlated with mean right atrial pressure, pulmonary vascular resistance, mean pulmonary artery pressure, tricuspid regurgitant velocity, 6-min walk distance and the New York Heart Association class. The area under the receiver operating curve for diagnosis of IPAH, based on serum NOTCH3-ECD, was 0.96 (95% confidence interval, 0.95-0.98) with a 90% sensitivity and 93% specificity at a cutoff of 13.0 ng ml-1. The 3-year mortality risk for individuals with IPAH increased by 18% for each increase in 3 ng ml-1 of NOTCH3-ECD above the diagnostic cutoff. The addition of serum NOTCH3-ECD levels improved the performance of prognostic calculators for PAH, including REVEAL 2.0, REVEAL 2.0 Lite and COMPERA 2.0. Moreover, serum NOTCH3-ECD levels predicted the presence of IPAH in treatment-naive individuals and correlated with disease progression over a follow-up of 6 years. Measurement of serum NOTCH3-ECD can therefore provide a highly sensitive, specific and noninvasive test for predicting the presence, disease severity, progression and survival of individuals with IPAH.

BACKGROUND:The association between immune-cell-specific transcriptomic profiles and mortality in idiopathic pulmonary fibrosis (IPF) is unknown. METHODS:We profiled peripheral blood mononuclear cells by single-cell RNA sequencing (scRNA-seq) and investigated which immune-cell-specific transcriptomic profile predicted IPF outcomes consistently. Prognostic accuracy was investigated in peripheral blood mononuclear cells (PBMCs), bronchoalveolar lavage (BAL) and lung tissue. Findings were validated by flow cytometry, analysis of independent scRNA-seq datasets and cellular deconvolution. We investigated the function of this transcriptomic profile and its cellular source in lung tissue (overall sample size, n=1054; IPF, n=555; other, n=499). Connectivity map analysis and LASSO regression were used to identify drug candidates and a subset of genes with prognostic potential, respectively. RESULTS:A 230-gene up-score (Pittsburgh PBMC cohort) from CD14+CD163-HLA-DRlow monocytes predicted mortality in the Chicago PBMC cohort (HR 6.58, 95% CI 2.15-20.13; p=0.001), in BAL pooled analysis (HR 2.20, 95% CI 1.44-3.37; p=0.0003), and negatively correlated with forced vital capacity in lung tissues (ρ= -0.2, p=0.02). Proportions of CD14+CD163-HLA-DRlow monocytes were higher in progressive versus stable IPF (12.59%, 95% CI 9.66-16.23%, versus 7.61%, 95% CI 6.68-10.21%; p=0.014). High-risk patients with IPF had decreased expression of T-cell co-stimulatory genes (Pittsburgh and Chicago, p<0.01). CD14+HLA-DRlow monocytes had higher expression of profibrotic, proangiogenic and chemotactic factors compared to CD14+HLA-DRhi monocytes (p<0.05). The 230-gene up-score correlated with the secreted phosphoprotein 1 (SPP1)+ fibrosis-associated macrophages gene-score in lung tissues (ρ=0.19, p<2.2e-16). Connectivity map analysis identified drug categories to reverse the 230-gene signature. A subset of six genes retained predictive performance (pooled PBMC cohorts HR 4.79, 95% CI 2.58-8.92; p<0.0001). CONCLUSIONS:The transcriptome of CD14+CD163-HLA-DRlow monocytes is associated with increased mortality in patients with IPF. Its reversal should be investigated as a precision-based therapy in IPF.

Mechanosensitive cation channels expressed in pulmonary arterial smooth muscle (SMC) and endothelial (EC) cells contribute to the regulation of vasoconstriction and vasodilation of the pulmonary vasculature. Here, we report that activating Piezo1, a mechanosensitive cation channel, with Yoda1 induced a mild increase in pulmonary arterial pressure (PAP) via vasoconstriction in the intact pulmonary vascular system. Inhibition of nitric oxide (NO) synthase (NOS) with l-NAME significantly potentiated Yoda1-mediated pulmonary vasoconstriction. The Yoda1-mediated vasoconstriction was inhibited by Gd3+, a non-selective blocker of cation channels, but not affected by nifedipine, a dihydropyridine blocker of voltage-dependent Ca2+ channels (VDCC). Alveolar hypoxia alone increased PAP via hypoxic pulmonary vasoconstriction (HPV); Yoda1-mediated pulmonary vasoconstriction overlaps with HPV in the isolated and perfused/ventilated lung. On top of the Yoda1-mediated increase in PAP, intrapulmonary perfusion of high K+ (25 mM) solution or phenylephrine (PE, 30 µM) induced an additional increase in PAP. These data indicate that, under normal conditions, the activation of Piezo1 (by Yoda1) caused pulmonary vasodilation due to Ca2+-associated activation of NOS in ECs and vasoconstriction due to Ca2+ influx in SMCs. In conclusion, Piezo1 or Ca2+ influx through Piezo1 in ECs and SMCs functions differently in the regulation of pulmonary vasculature. When the endothelium-derived relaxing factor (e.g., NO) is decreased due to EC injury and/or inflammation, Piezo1 or Ca2+ influx through Piezo1 channels is an important trigger for pulmonary vasoconstriction in the whole-lung vascular system.

Background: Polymorphonuclear (PMN) leukocyte recruitment to activated pulmonary endothelium is a central mechanism in acute respiratory distress syndrome (ARDS). This process is mediated by selectins and their counter-ligand, P-selectin glycoprotein ligand-1 (PSGL-1), encoded by SELPLG. Genetic variation in SELPLG has been associated with ARDS susceptibility, while disruption of PSGL-1/P-selectin interactions attenuates lung injury in preclinical models. Because inflammatory stimuli increase both SELPLG expression and circulating PSGL-1 levels, PSGL-1 represents a promising biomarker and therapeutic target. We sought to define the genetic determinants of plasma PSGL-1 levels and evaluate their causal relationships with key inflammatory and endothelial biomarkers. Methods: Genome-wide association study (GWAS) summary statistics for plasma PSGL-1 levels were obtained from the UK Biobank Pharma Proteomics Project (n=35,571) and the SCALLOP consortium (n=21,758 across 13 cohorts). Associated variants underwent functional annotation and in-silico analyses to identify potential effects on protein structure and gene regulation. Bidirectional Mendelian randomization (MR) was performed using GWAS summary statistics for C-reactive protein (CRP), E-selectin, GlycA, and soluble intercellular adhesion molecule-1 (sICAM-1) to assess potential causal relationships with PSGL-1 levels. Results: Multiple cis- and trans-acting loci were significantly associated with plasma PSGL-1 concentrations. Three coding SELPLG variants (rs201689859, rs74792300, and rs139943851) were predicted to alter PSGL-1 protein structure and were associated with lower circulating PSGL-1 levels. Four promoter variants (rs1420663, rs1833245, rs1420664, and rs8179110) were linked to altered transcriptional activity, including a potential effect of rs1420664 on hypoxia-inducible factor binding. Bidirectional MR demonstrated that genetically predicted CRP, E-selectin, GlycA, and sICAM-1 levels were associated with increased plasma PSGL-1 concentrations. Additional loci implicated pathways related to immune signaling, cell adhesion, and protein stability. Conclusions: Large-scale GWAS and Mendelian randomization analyses identified genetic variants that regulate plasma PSGL-1 levels and demonstrated causal links between inflammatory and endothelial biomarkers and PSGL-1 expression. These findings provide new insights into the genetic regulation of leukocyte trafficking pathways and support a role for PSGL-1 in inflammatory diseases, including ARDS, sepsis, and cardiovascular disorders.

NRF2 is a master regulator of redox and metabolic homeostasis that protects normal tissues from stress but is frequently hijacked by cancers to sustain survival and therapy resistance. Although NRF2 is dispensable for normal tissue function, its role in maintaining cancer cells within the native tumor microenvironment has remained undefined. Here, we uncover an essential and previously unrecognized tumor-specific dependency on NRF2. Using an inducible KrasFSF.G12D/+;Nrf2Fl/Fl;Rosa26CreERT2/CreERT2 (KNR) mouse lung cancer model, we demonstrate that NRF2 deletion alone, without pharmacologic intervention, eradicates cancer cells, reduces tumor burden, and prolongs survival. Single-cell RNA sequencing coupled with artificial intelligence-based genotype classification revealed that NRF2-deleted cancer cells are selectively eliminated, whereas non-cancerous cells tolerate NRF2 loss. Mechanistically, NRF2 deletion induces ferroptosis, a regulated iron-dependent cell death pathway, evidenced by induction of canonical ferroptotic genes (Ptgs2, Acsl4, Tfrc) and protein markers (SO2/3-PRDX3, COX2, TfR1). Importantly, these data support that NRF2 loss induces ferroptotic cell death in vivo within established tumors, in the absence of exogenous ferroptosis inducers or external stress. These findings establish that cancer cells depend on NRF2 to suppress intrinsic ferroptotic stress for survival, a dependency not shared by normal tissues. This discovery fundamentally redefines the pathological role of NRF2 and positions NRF2 inhibition as a standalone, tumor-selective therapeutic strategy to eliminate Kras-driven malignancies by unleashing ferroptosis.

NAMPT is an important intracellular metabolic enzyme (iNAMPT) regulating the NAD+ salvage pathway. However, increased cellular stress (infection, inflammation, hypoxia) promotes the secretion of extracellular NAMPT (eNAMPT), a TLR4 ligand and damage-associated molecular pattern protein (DAMP) that directly drives amplification of innate immune-mediated inflammatory, fibrotic, and neoplastic responses to influence disease severity. We sought to examine the mechanisms underlying pyroptotic eNAMPT release from human monocytic THP-1 cells, evoked by Nigericin, and non-pyroptotic eNAMPT secretion elicited by lipopolysaccharide (LPS). Our data indicate eNAMPT secretion/release requires NLRP3 inflammasome activation with substantial attenuation by either NLRP3 inhibition (MCC-950) or targeted genetic deletion of key inflammasome components, including NLRP3, caspase-1, or gasdermin D (GSDMD). Pyroptosis-associated eNAMPT release involved cleavage of the pore-forming GSDMD protein resulting in plasma membrane rupture (PMR) whereas non-pyroptotic LPS-induced eNAMPT secretion involved neither GSDMD cleavage nor PMR, verified utilizing non-cleavable GSDMD mutant constructs. LPS-induced eNAMPT secretion, however, was highly dependent upon NAMPT ubiquitination catalyzed by a complex containing the NEDD4 E3 ligase, Hsp90 (a selective chaperone), and intact GSDMD verified by enzymatic inhibition or silencing of NEDD4, GSDMD, or Hsp90. NAMPT ubiquitination and secretion involves autophagy activation as super-resolution microscopy analyses demonstrate NAMPT co-localization with autophagosome marker LC3B and eNAMPT secretion was significantly reduced by targeted ATG5 and ATG7 inhibition, critical components of the autophagy E3-like complex. These studies provide key insights into eNAMPT secretion that may accelerate the development of therapeutic strategies that address unmet therapeutic needs in inflammatory, fibrotic and neoplastic disorders.

RATIONALE: The lung-brain axis has emerged as a significant area of clinical importance with central nervous system and respiratory system injuries demonstrating bi-directional impact. Unfortunately, effective therapeutics for addressing this pathological cross talk remains an unmet need, due in part to the absence of reliable biomarkers that reflect the severity of lung-brain axis disruption. We assessed specific biomarkers in subjects with traumatic brain injury (TBI), a major public health concern affecting 1.4million Americans annually, and subjects with Acute Respiratory Distress Syndrome (ARDS), a life-threatening inflammatory lung injury responsible for more than 10% of ICU admissions each year with a 30-40% mortality. METHODS: Serum collected from TBI subjects (n=63, ∼47y/o, ∼20hr post), ARDS (n=39, ∼52y/o, ∼ day 1), and healthy patients (n=40, ∼50y/o) was analyzed via Meso Scale Discovery ELISA for inflammatory biomarkers (eNAMPT, IL-6, PSGL-1, ANG-2, IL-1β, IL-1RA, TNF-α, S100A8) and neurotrauma biomarkers (Glial fibrillary acidic protein [GFAP], Neuro filament light chain [NFL], Tau). Outliers were removed via ROUT analysis; results were analyzed utilizing Mann-Whitney, Kruskal-Wallis w/ Dunn, and Receiver Operating Characteristic (ROC) Curve analysis. RESULTS: All biomarkers were significantly elevated in TBI patients compared to controls except for PSGL-1 (4xeNAMPT, 21x IL-6, 2x Ang-2, 13x IL-1β,3x IL-1RA, 2x TNF-α, 3x S100A8, 136xGFAP, 9x NFL, 9x Tau). ARDS patients demonstrated significantly elevated levels of all biomarkers compared to controls except for GFAP (8x eNAMPT, 12x IL-6, 5xAng-2, 13x IL-1β, 6x IL-1RA, 1.3xPSGL-1, 3x TNF-α, 3x S100A8, 11x NFL, 5xTau). Comparing ARDS to TBI, IL-6 was significantly higher in TBI subjects (2x)whereas eNAMPT, TNF-α, and Ang-2 were all significantly elevated (2x) in ARDS. GFAP was significantly elevated only in TBI. CONCLUSIONS: The elevations in inflammatory biomarkers in TBI- and ARDS-exposed subjects without neuro trauma reflect shared activation of innate immunity consistent with the observation that 25% of TBI patients develop lung injury (including ARDS) supporting lung brain axis disruption. GFAP appears to be a TBI-specific biomarker with the elevations in NFL and Tau in ARDS subjects potentially reflecting peripheral neurological damage without lung brain axis disruption. Longitudinal studies of well-phenotyped TBI and ARDS subjects are needed to disclose the integrated inflammatory responses and the value of inflammatory biomarker testing to detect bidirectional injuries.

Acute Respiratory Distress Syndrome (ARDS), characterized by the rapid onset of respiratory failure and mortality rates of ∼40%, remains a significant challenge in critical care medicine. Despite advances in supportive care, accurate prediction of ARDS mortality remains challenging, resulting in delayed delivery of targeted interventions and effective disease management. Traditional critical illness severity scores lack specificity for ARDS, underscoring the need for more precise prognostic tools for ARDS mortality. To address this crucial gap, we employed a multimodal approach to predict ARDS patients utilizing a comprehensive dataset comprised of integrated clinical, metabolomic, and biochemical/cytokine data from ARDS patients (collected within hours of ICU admission) to develop and validate predictive models of ARDS mortality risk. The most robust multimodal data model generated demonstrated superior predictive capability with an area under the curve (AUC) of 0.868 on the test set and 0.959 on the validation set. Notably, this model achieved perfect specificity in identifying non-survivors in the validation cohort, highlighting potential utility in guiding early and targeted interventions in ICU settings. Metabolomic analysis revealed significant alterations in crucial pathways associated with ARDS mortality with tryptophan metabolism, particularly the kynurenine pathway, emerging as the most significantly enriched metabolic route, as well as the NAD+ metabolism/nicotinamide phosphoribosyltransferase (NAMPT) and glycosaminoglycan biosynthesis pathways. These metabolic derangements were strongly confirmed by lipidomic/metabolomic analysis of lung tissues from a porcine sepsis/ARDS model. Together, these findings demonstrate the promise of integrating multimodal data to improve ARDS prognostication and to provide important insights into the complex metabolic derangements underlying severe ARDS. Identification of metabolic signatures, such as kynurenine and NAD+ metabolism/NAMPT pathways, may serve as a foundation for developing personalized and effective targeted interventions and management strategies for ARDS patients.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disorder without curative therapies, underscoring the critical unmet need for identification of novel therapeutic strategies. eNAMPT (extracellular nicotinamide phosphoribosyltransferase) is a damage-associated molecular pattern protein (DAMP) and TLR4 (Toll-like receptor 4) ligand that contributes to the severity of radiation-induced lung fibrosis and nonalcoholic steatohepatitis-associated hepatic fibrosis. This study investigates eNAMPT as a druggable target in human and preclinical IPF using the eNAMPT-neutralizing ALT-100 monoclonal antibody (mAb). Blood, peripheral blood mononuclear cells (PBMCs), and lung tissues from patients with IPF and from an experimental bleomycin-induced lung fibrosis model in C57Bl6 mice were analyzed. Biochemical and histologic measurements, as well as gene expression through bulk and single-cell RNA sequencing of human PBMCs and murine lung tissues, were performed. Human studies revealed NAMPT expression to be significantly increased in plasma, lung tissues, and PBMCs from subjects with IPF, correlating with disease severity and inversely associated with IPF survival. Bleomycin-exposed mice exhibited increased inflammatory indices associated with lung fibrosis development (including NAMPT levels), as well as physiologic lung stiffening and TGF-β pathway-related protein and gene expression, with each index significantly mitigated in mice receiving ALT-100 mAb. Single-cell RNA sequencing studies demonstrated the ALT-100 mAb to reverse the bleomycin-induced dramatic expansion of alveolar type 2 epithelium and induction of endothelial cell- and epithelial cell-to-mesenchymal/myofibroblast transitions. These finding support the fundamental involvement of eNAMPT/TLR4 signaling pathway in lung fibrosis pathobiology, with eNAMPT neutralization a viable therapeutic strategy to directly address the unmet need for novel IPF treatments.

BACKGROUND:The attenuation of cellular phenotypic switchingdriving PAH vascular remodeling remains an unmet therapeutic need. As eNAMPT (nicotinamide phosphoribosyltransferase)/TLR4 signaling significantly contributes to PH pathobiology, an eNAMPT-neutralizing ALT-100 mAb was utilized to rescue monocrotaline (MCT) and hypoxia/Sugen (Hy/Su) preclinical PH rat models and to evaluate eNAMPT/TLR4 involvement in endothelial cell (EC), smooth muscle cell (SMC) and monocyte/macrophage phenotypic switching. METHODS:MCT-PH or Hy/Su-PH rats received IgG or ALT-100 mAb (subQ, beginning week 4) with measurements of PH severity and lung tissue scRNAseq at day 42. RESULTS:PH severity indices (hemodynamic, histologic, vascular remodeling) were significantly attenuated in MCT-PH and Hy/Su-PH rats receiving ALT-100 mAb. scRNAseq studies revealed Hy/Su exposure increased populations of ECs undergoing EC-to-mesenchymal cell transition (EndMT), proliferating SMCs, and monocytes undergoing macrophage differentiation. Cellular phenotypic switching was ameliorated in Hy/Su-mAb rats. CONCLUSIONS:Autocrine/paracrine eNAMPT/TLR4 signaling contributes to accelerated cellular phenotypic switching, a druggable strategy to reverse vascular remodeling.

Hepatocellular carcinoma (HCC), the most common form of primary liver cancer, is the third leading cause of cancer-related mortality globally. Current systemic therapies for HCC are limited and often exhibit unsatisfactory efficacy, underscoring the need for novel therapeutic approaches. Nuclear factor erythroid 2-related factor-2 (NRF2), a master transcription factor regulating cellular redox and metabolic homeostasis, is frequently overexpressed in HCC due to mutations in NFE2L2/NRF2 or its negative regulator Kelch-like ECH-associated protein 1 (KEAP1), contributing to tumor progression. In this study, we identify CYP4F11, a member of the Cytochrome P450 family, as a direct target gene of NRF2. CYP4F11, primarily expressed in the liver, is crucial in fatty acid oxidation and eicosanoid metabolism. We demonstrate that CYP4F11 expression is driven by NRF2 and is significantly elevated in HCC patients harboring NFE2L2 gain of function or KEAP1 loss of function mutations. Functionally, CYP4F11 promotes HCC cell growth, and reduced expression of CYP4F11 not only suppresses HCC cell proliferation but also enhances sorafenib-induced HCC cell death. Further, NRF2 inhibition sensitizes HCC to sorafenib through downregulation of CYP4F11. These findings position CYP4F11 as a novel contributor to HCC progression and highlight the potential of targeting the NRF2-CYP4F11 axis for HCC treatment.

ChAT-expressing T cells represent similar to 0.01 % of total circulating T lymphocytes in adult wild-type mice. However, we previously reported that systemic infusion of ChAT+ve Jurkat T cells into adult mice elicits vasodilation and instantaneous decline in the mean systolic blood pressure, suggesting potential as a biologic therapeutic to attenuate pathologic increases in pulmonary arterial pressures. We now report that ChAT gene-expressing Jurkat cells dose-dependently decrease right ventricular systolic pressures (RVSP) in hypoxic mice and that transgenic mice with ChAT KO restricted to endothelial cells (KO END/ChAT-/-) exhibit significantly elevated pulmonary arterial pressure and peripheral systemic resistance (compared to WT mice). To rigorously characterize the role of CD4 ChAT+ T cells in regulating pulmonary arterial hypertension (PAH) hemodynamics and molecular signatures, we infused CD4+ ChAT+ve cells (0.5 to 2.0 million cells/animal) into adult PAH mice and noted significant reductions in RVSP within 2-3 min post injection (similar to 50 % reduction). The tailored tail vein injection effect was sustained until the animal was euthanized (30-40 min). Mice KO END/ChAT-/-showed a significant and severe hypoxia-induced PAH phenotype compared to WT adult mice. Tail vein injection of biologically active CD4 ChAT+ve cells into either KO END/ChAT-/-mice with hypoxia-induced PAH or into adult rats with hypoxia/Sugen-induced PAH resulted in significant attenuation of RVP elevations. RNA seq data analysis of human pulmonary endothelial cells (HPAECs) incubated with CD4 ChAT+ve T cells showed significant differential regulation of pathways involved in systemic and pulmonary pressure regulation, NO synthesis/regulation, antioxidant expression, and vasodilation. In conclusion, CD4 ChAT+ve T cells have a unique, vasodilating innate immunity mechanism to augment nitric oxide release and potentially mitigate molecular and genetic pathways involved in PAH pathogenesis.

Sphingosine-1-phosphate receptors (S1PRs) are a family of G protein-coupled transmembrane proteins that play essential roles across nearly all organ systems, including the regulation of pulmonary physiology and immune responses. Expressed across diverse lung cell types, S1PRs mediate critical biological processes such as vascular barrier integrity, immune cell trafficking, and inflammation. While the signaling pathways and physiological functions of S1PR1 and S1PR3 have been extensively characterized, the role of S1PR2 remains less clearly defined and context-dependent. In this review, we summarize current knowledge on S1PR2 signaling within major pulmonary cell populations and explore its contribution to lung homeostasis and disease. By synthesizing evidence from molecular, cellular and in vivo studies, this review aims to summarize the current understanding of S1PR2 signaling across major pulmonary cell populations and its roles in lung homeostasis and disease. The findings of this study could help develop new strategies for treating pulmonary disorders and other diseases by targeting S1PR2.

Objective:Human and preclinical studies of sulfur mustard (SM)-induced acute and chronic lung injuries highlight the role of unremitting inflammation. We assessed the utility of targeting the novel DAMP and TLR4 ligand, eNAMPT (extracellular nicotinamide phosphoribosyltransferase), utilizing a humanized mAb (ALT-100) in rat models of SM exposure.Methods:Acute (SM 4.2 mg/kg, 24 hrs), subacute (SM 0.8 mg/kg, day 7), subacute (SM 2.1 mg/kg, day 14), and chronic (SM 1.2 mg/kg, day 29) SM models were utilized.Results:Each SM model exhibited significant increases in eNAMPT expression (lung homogenates) and increased levels of phosphorylated NFkB and NOX4. Lung fibrosis (Trichrome staining) was observed in both sub-acute and chronic SM models in conjunction with elevated smooth muscle actin (SMA), TGFβ, and IL-1β expression. SM-exposed rats receiving ALT-100 (1 or 4 mg/kg, weekly) exhibited increased survival, highly significant reductions in histologic/biochemical evidence of lung inflammation and fibrosis (Trichrome staining, decreased pNFkB, SMA, TGFβ, NOX4), decreased airways strictures, and decreased plasma cytokine levels (eNAMPT, IL-6, IL-1β. TNFα).Conclusion:The highly druggable, eNAMPT/TLR4 signaling pathway is a key contributor to SM-induced ROS production, inflammatory lung injury and fibrosis. The ALT-100 mAb is a potential medical countermeasure to address the unmet need to reduce SM-associated lung pathobiology/mortality.

Increased levels of extracellular nicotinamide phosphoribosyltransferase (eNAMPT) are increasingly recognized as a highly useful biomarker of inflammatory disease and disease severity. In preclinical animal studies, a monoclonal antibody that neutralizes eNAMPT has been generated to successfully reduce the extent of inflammatory cascade activation. Thus, the rapid detection of eNAMPT concentration in plasma samples at the point of care (POC) would be of great utility in assessing the benefit of administering an anti-eNAMPT therapeutic. To determine the feasibility of this POC test, we conducted a particle immunoagglutination assay on a paper microfluidic platform and quantified its extent with a flow rate measurement in less than 1 min. A smartphone and cloud-based Google Colab were used to analyze the flow rates automatically. A horizontal flow model and an immunoagglutination binding model were evaluated to optimize the detection time, sample dilution, and particle concentration. This assay successfully detected eNAMPT in both human whole blood and plasma samples (diluted to 10 and 1%), with the limit of detection of 1-20 pg/mL (equivalent to 0.1-0.2 ng/mL in undiluted blood and plasma) and a linear range of 5-40 pg/mL. Furthermore, the smartphone POC assay distinguished clinical samples with low, mid, and high eNAMPT concentrations. Together, these results indicate this POC assay, which utilizes low-cost materials, time-effective methods, and a straightforward immunoassay (without surface immobilization), may reliably allow rapid determination of eNAMPT blood/plasma levels to advantage patient stratification in clinical trials and guide ALT-100 mAb therapeutic decision-making.

AIMS/HYPOTHESIS:Individuals with diabetes are at high risk of cardiovascular complications, which significantly increase morbidity/mortality. Coronary microvascular disease (CMD) is recognised as a critical contributor to the increased cardiac mortality observed in people with diabetes. Therefore, there is an urgent need for treatments that are specific to CMD. eNAMPT (extracellular nicotinamide phosphoribosyltransferase) is a damage-associated molecular pattern and TLR4 ligand, whose plasma levels are elevated in people with diabetes. This study was thus designed to investigate the pathogenic role of intracellular nicotinamide phosphoribosyltransferase (iNAMPT) and eNAMPT in promoting the development of CMD in a preclinical murine model of type 2 diabetes. METHODS:An inducible type 2 diabetic mouse model was generated by a single injection of low-dose streptozocin (75 mg/kg, i.p.) combined with a high-fat diet for 16 weeks. The in vivo effects of i/eNAMPT inhibition on cardiac endothelial cell (CEC) function were evaluated by using Nampt+/- heterozygous mice, chronic administration of eNAMPT-neutralising monoclonal antibody (mAb) or use of an NAMPT enzymatic inhibitor (FK866). RESULTS:As expected, diabetic wild-type mice exhibited significantly lower coronary flow velocity reserve (CFVR), a determinant of coronary microvascular function, compared with control wild-type mice. eNAMPT plasma levels or expression in CECs were significantly greater in diabetic mice than in control mice. Furthermore, in comparison with diabetic wild-type mice, diabetic Nampt+/- heterozygous mice showed markedly improved CFVR, accompanied by increased left ventricular capillary density and augmented endothelium-dependent relaxation (EDR) in the coronary artery. NAMPT inhibition by FK866 or an eNAMPT-neutralising mAb significantly increased CFVR in diabetic mice. Furthermore, administration of the eNAMPT mAb upregulated expression of angiogenesis- and EDR-related genes in CECs from diabetic mice. Treatment with either eNAMPT or NAD+ significantly decreased CEC migration and reduced EDR in coronary arteries, partly linked to increased production of mitochondrial reactive oxygen species. CONCLUSIONS/INTERPRETATION:These data indicate that increased i/eNAMPT expression contributes to the development of diabetic coronary microvascular dysfunction, and provide compelling support for eNAMPT inhibition as a novel and effective therapeutic strategy for CMD in diabetes.