Transcriptional Suppression of CPI-17 Gene Expression in Vascular Smooth Muscle Cells by Tumor Necrosis Factor, Krüppel-Like Factor 4, and Sp1 Is Associated with Lipopolysaccharide-Induced Vascular Hypocontractility, Hypotension, and Mortality

Endothelial cell dynamics in sepsis-induced acute lung injury and acute respiratory distress syndrome: pathogenesis and therapeutic implications

Sepsis, a prevalent critical condition in clinics, continues to be the leading cause of death from infections and a global healthcare issue. Among the organs susceptible to the harmful effects of sepsis, the lungs are notably the most frequently affected. Consequently, patients with sepsis are predisposed to developing acute lung injury (ALI), and in severe cases, acute respiratory distress syndrome (ARDS). Nevertheless, the precise mechanisms associated with the onset of ALI/ARDS remain elusive. In recent years, there has been a growing emphasis on the role of endothelial cells (ECs), a cell type integral to lung barrier function, and their interactions with various stromal cells in sepsis-induced ALI/ARDS. In this comprehensive review, we summarize the involvement of endothelial cells and their intricate interplay with immune cells and stromal cells, including pulmonary epithelial cells and fibroblasts, in the pathogenesis of sepsis-induced ALI/ARDS, with particular emphasis placed on discussing the several pivotal pathways implicated in this process. Furthermore, we discuss the potential therapeutic interventions for modulating the functions of endothelial cells, their interactions with immune cells and stromal cells, and relevant pathways associated with ALI/ARDS to present a potential therapeutic strategy for managing sepsis and sepsis-induced ALI/ARDS.

Cognitive impairment in patients with heart failure: molecular mechanism and therapy

Heart failure (HF) is associated with multiple organ dysfunction and many comorbidities. Its incidence is high among the elderly and is a major health burden worldwide. Cognitive impairment (CI) is highly prevalent in older patients with HF, which is an abnormality in one or more of the items of cognition, attention, memory, language, psychomotor function, and visual spatial acuity. Studies have shown that the incidence of CI in HF patients is between 13 and 54%, and patients with both conditions have poor self-care ability and prognosis, as well as increased mortality rates. However, the mechanisms of CI development in HF patients are still unclear. In this review, we describe the epidemiology and risk factors as well as measures of improving CI in HF patients. We update the latest pathophysiological mechanisms related to the neurocognitive changes in HF patients, expounding on the mechanisms associated with the development of CI in HF patients.

Role of sympathetic pathway in light-phase time-restricted feeding-induced blood pressure circadian rhythm alteration

Disruption of blood pressure (BP) circadian rhythm, independent of hypertension, is emerging as an index for future target organ damage and is associated with a higher risk of cardiovascular events. Previous studies showed that changing food availability time alters BP rhythm in several mammalian species. However, the underlying mechanisms remain largely unknown. To address this, the current study specifically investigates (1) the relationship between rhythms of food intake and BP in wild-type mice; (2) effects of light-phase time-restricted feeding (TRF, food only available during light-phase) on BP circadian rhythm in wild-type and diabetic db/db mice; (3) the roles of the autonomic system and clock gene in light-phase TRF induced changes in BP circadian rhythm. Food intake and BP of C57BL/6J and db/db mice were simultaneously and continuously recorded using BioDAQ and telemetry systems under ad libitum or light-phase TRF. Per2 protein daily oscillation was recorded in vivo by IVIS spectrum in mPer2 Luc mice. Autonomic nerve activity was evaluated by heart rate variability, baroreflex, urinary norepinephrine (NE) and epinephrine (Epi) excretion, and mRNA expressions of catecholamines biosynthetic and catabolic enzymes, and alpha-adrenergic receptors in mesenteric resistance arteries. We found that in wild-type mice, the BP level was correlated with the food intake temporally across the 24 h. Reversing the feeding time by imposing light-phase TRF resulted in reverse or inverted BP dipping. Interestingly, the net changes in food intake were correlated with the net alteration in BP temporally under light-phase TRF. In db/db mice, light-phase TRF worsened the existing non-dipping BP. The food intake and BP circadian rhythm changes were associated with alterations in Per2 protein daily oscillation and the time-of-day variations in heart rate variability, baroreflex, and urinary excretion of NE and Epi, and increased mRNA expression of Slc6a2 (encoding NE transporter) and Adra1d (encoding alpha-adrenergic receptor 1d) in the mesenteric resistance arteries, indicating the sympathetic nervous system (SNS) was modulated after light-phase TRF. Collectively, our results demonstrated that light-phase TRF results in reverse dipping of BP in wild-type and diabetic db/db mice and revealed the potential role of the sympathetic pathway in light-phase TRF-induced BP circadian rhythm alteration.

Extracellular histones induce inflammation and senescence of vascular smooth muscle cells by activating the AMPK/FOXO4 signaling pathway

BACKGROUND

Sepsis is an abnormal immune-inflammatory response that is mainly caused by infection. It can lead to life-threatening organ dysfunction and death. Severely damaged tissue cells will release intracellular histones into the circulation as damage-related molecular patterns (DAMPs) to accelerate the systemic immune response. Although various histone-related cytotoxicity mechanisms have been explored, those that affect extracellular histones involved in vascular smooth muscle cell (VSMC) dysfunction are yet to be determined.

METHODS

Mouse aortic vascular smooth muscle cells (VSMCs) were stimulated with different concentrations of histones, and cell viability was detected by CCK-8 assay. Cellular senescence was assessed by SA β-gal staining. C57BL/6 mice were treated with histones with or without BML-275 treatment. RT-qPCR was performed to determine the expression of inflammatory cytokines. Western blotting was used to analyze the expression of NLRP3, ASC and caspase-1 inflammasome proteins. The interaction of NLRP3 and ASC was detected by CoIP and immunofluorescence staining.

RESULTS

In this study, we found that extracellular histones induced senescence and inflammatory response in a dose-dependent manner in cultured VSMCs. Histone treatment significantly promoted apoptosis-associated speck-like protein containing CARD (ASC) as well as NACHT, LRR and PYD domains-containing protein 3 (NLRP3) interaction of inflammasomes in VSMCs. Forkhead box protein O4 (FOXO4), which is a downstream effector molecule of extracellular histones, was found to be involved in histone-regulated VSMC inflammatory response and senescence. Furthermore, the 5'-AMP-activated protein kinase (AMPK) signaling pathway was confirmed to mediate extracellular histone-induced FOXO4 expression, and blocking this signaling pathway with an inhibitor can suppress vascular inflammation induced by extracellular histones in vivo and in vitro.

CONCLUSION

Extracellular histones induce inflammation and senescence in VSMCs, and blocking the AMPK/FOXO4 pathway is a potential target for the treatment of histonemediated organ injury.

microRNA-124-3p attenuates myocardial injury in sepsis via modulating SP1/HDAC4/HIF-1α axis

Sepsis-induced cardiac dysfunction can lead to death in sepsis. In this case, we targeted to explore in detail the relative mechanism of microRNA (miR)-124-3p in sepsis-induced myocardial injury via the specific protein 1/histone deacetylase 4/hypoxia-inducing factor 1α (SP1/HDAC4/HIF-1α) axis. Septic rats were modeled by cecal ligation puncture while in vitro septic cardiomyocyte H9C2 were induced by lipopolysaccharide (LPS). miR-124-3p/SP1/HDAC4/HIF-1α expression levels in myocardial tissues of septic rats and LPS-treated H9C2 cells were measured. miR-124-3p overexpression and SP1 silencing assays were implemented on LPS-treated H9C2 cells to explore theirs actions in inflammation, oxidative stress and cell apoptosis. The interactions of miR-124-3p, SP1, and HDAC4 were testified. miR-124-3p was lowly expressed while SP1, HDAC4, and HIF-1α were highly expressed in sepsis. Upregulation of miR-124-3p ameliorated inflammation, oxidative stress, and apoptosis of LPS-treated H9C2 cells. Silencing SP1 improved LPS-induced damage to cardiomyocytes. miR-124-3p targeted SP1 and HDAC4 interacted with SP1. SP1 overexpression antagonized miR-124-3p upregulation-induced improvements in LPS-induced cardiomyocyte damage. This study illustrates that miR-124-3p improves myocardial injury in septic rats through targeted regulation of SP1 to mediate HDAC4/HIF-1α.

Novel role of prostate cancer risk variant rs7247241 on PPP1R14A isoform transition through allelic TF binding and CpG methylation

Although previous studies identified numerous single nucleotide polymorphisms (SNPs) and their target genes predisposed to prostate cancer (PrCa) risks, SNP-related splicing associations are rarely reported. In this study, we applied distance-based sQTL analysis (sQTLseekeR) using RNA-seq and SNP genotype data from benign prostate tissue (n = 467), and identified significant associations in 3344 SNP-transcript pairs (P ≤ 0.05) at PrCa risk loci. We characterized a common SNP (rs7247241) and its target gene (PPP1R14A) located in chr19q13, a sQTL with risk allele T associated with upregulation of long isoform (P = 9.99E-7). We confirmed the associations in both TCGA (P = 2.42E-24) and GTEX prostate cohorts (P = 9.08E-78). To functionally characterize this SNP, we performed chromatin Immunoprecipitation qPCR and confirmed stronger CTCF and PLAGL2 binding in rs7247241 C than T allele. We found that CTCF binding enrichment was negatively associated with methylation level at the SNP site in human cell lines (r = -0.58). Bisulfite sequencing showed consistent association of rs7247241-T allele with nearby sequence CpG hypermethylation in prostate cell lines and tissues. Importantly, the methylation level at CpG sites nearest to the CTCF binding and first exon splice-in (ψ) of PPP1R14A were significantly associated with aggressive phenotype in the TCGA PrCa cohort. Meanwhile, the long isoform of the gene also promoted cell proliferation. Taken together, with the most updated gene annotations, we reported a set of sQTL associated with multiple traits related to human prostate diseases, and revealed a unique role of PrCa risk SNP rs7247241 on PPP1R14A isoform transition.

Characterization of Contractile Machinery of Vascular Smooth Muscles in Hypertension

Hypertension is a key risk factor for cardiovascular disease and it is a growing public health problem worldwide. The pathophysiological mechanisms of vascular smooth muscle (VSM) contraction contribute to the development of hypertension. Calcium (Ca²⁺)-dependent and -independent signaling mechanisms regulate the balance of the myosin light chain kinase and myosin light chain phosphatase to induce myosin phosphorylation, which activates VSM contraction to control blood pressure (BP). Here, we discuss the mechanism of the contractile machinery in VSM, especially RhoA/Rho kinase and PKC/CPI-17 of Ca²⁺ sensitization pathway in hypertension. The two signaling pathways affect BP in physiological and pathophysiological conditions and are highlighted in pulmonary, pregnancy, and salt-sensitive hypertension.

A temporal Ca2+-desensitization of myosin light chain kinase in phasic smooth muscles induced by CaMKKß/PP2A pathways

Cell signaling pathways regulating myosin regulatory light chain (LC20) phosphorylation contribute to determining contractile responses in smooth muscles. Following excitation and contraction, phasic smooth muscles, such as digestive tract and urinary bladder, undergo a relaxation due to a decline of cellular [Ca²⁺] and a decreased Ca²⁺ sensitivity of LC20 phosphorylation, named Ca²⁺ desensitization. Here, we determined mechanisms underlying the temporal Ca²⁺ desensitization of LC20 phosphorylation in phasic smooth muscles using permeabilized strips of mouse ileum and urinary bladder. Upon the stimulation with pCa6.0 at 20°C, the contraction and the LC20 phosphorylation peaked within 30 sec and then declined to about 50% of the peak force at 2 min after stimulation. During the relaxation phase after the contraction, the LC20 kinase (MLCK) was inactivated, but no fluctuation in the LC20 phosphatase activity occurred, suggesting that the MLCK inactivation is a cause of the Ca²⁺-induced Ca²⁺-desensitization of LC20 phosphorylation. The MLCK inactivation was associated with phosphorylation at the calmodulin binding domain of the kinase. Treatment with antagonists for CaMKKß (STO-609 and TIM-063) attenuated both the phasic response of the contraction and MLCK phosphorylation, whereas neither CaMKII, AMPK nor PAK induced the MLCK inactivation in phasic smooth muscles. Conversely, PP2A inhibition amplified the phasic response. Signaling pathways through CaMKKß and PP2A may contribute to regulating the Ca²⁺ sensitivity of MLCK and the contractile response of phasic smooth muscles.