Kielin/chordin-like protein deficiency aggravates pressure overload-induced cardiac dysfunction and remodeling via P53/P21/CCNB1 signaling in mice.

Targeting cardiac remodeling is regarded as a key therapeutic strategy for heart failure. Kielin/chordin-like protein (KCP) is a secretory protein with 18 cysteine-rich domains and associated with kidney and liver fibrosis. However, the relationship between KCP and cardiac remodeling remains unclear. Here, we aimed to investigate the role of KCP in cardiac remodeling induced by pressure overload and explore its potential mechanisms. Left ventricular (LV) KCP expression was measured with real-time quantitative PCR, western blotting, and immunofluorescence staining in pressure overload-induced cardiac remodeling in mice. Cardiac function and remodeling were evaluated in wide-type (WT) mice and KCP knockout (KO) mice by echocardiography, which were further confirmed by histological analysis with hematoxylin and eosin and Masson staining. RNA sequence was performed with LV tissue from WT and KO mice to identify differentially expressed genes and related signaling pathways. Primary cardiac fibroblasts (CFs) were used to validate the regulatory role and potential mechanisms of KCP during fibrosis. KCP was down-regulated in the progression of cardiac remodeling induced by pressure overload, and was mainly expressed in fibroblasts. KCP deficiency significantly aggravated pressure overload-induced cardiac dysfunction and remodeling. RNA sequence revealed that the role of KCP deficiency in cardiac remodeling was associated with cell division, cell cycle, and P53 signaling pathway, while cyclin B1 (CCNB1) was the most significantly up-regulated gene. Further investigation in vivo and in vitro suggested that KCP deficiency promoted the proliferation of CFs via P53/P21/CCNB1 pathway. Taken together, these results suggested that KCP deficiency aggravates cardiac dysfunction and remodeling induced by pressure overload via P53/P21/CCNB1 signaling in mice.

Metabolic Dysfunction-associated Steatotic Liver Disease is Becoming the Leading Driver of the Burden of Cirrhosis in China: Results From the Global Burden of Disease Study 2019.

OBJECTIVE: Cirrhosis and other chronic liver diseases (generally referred to as cirrhosis in this article) are major causes of morbidity and mortality in China. The disease pattern of cirrhosis caused by different etiologies has been changing due to economic development and changes in lifestyle. METHODS: Prevalence, incidence, disability-adjusted life-years, and mortality data were retrieved from the Global Burden of Disease study, 2019. Estimated annual percentage change was used to quantify the trends in the age-standardized prevalence rate and prevalence number of cirrhosis from 1990 to 2019. We presented the results for five causes of cirrhosis, and for different age and sex groups. RESULTS: Nationwide, we found that the prevalence number of liver cirrhosis increased steadily (from 3025.3×105 to 4279.8×105) from 1990 to 2019. Notably, the age-standardized prevalence rate of cirrhosis caused by metabolic dysfunction-associated steatotic liver disease (MASLD) increased throughout the study period, and MASLD has exceeded the hepatitis B virus and become the leading cause of liver cirrhosis since 1992. The highest prevalence number of MASLD occurred in the young population aged between 15 to 49 years. CONCLUSION: The prevalence of liver cirrhosis caused by hepatitis B virus decreased, whereas the prevalence of liver cirrhosis caused by MASLD increased. MASLD has become the leading cause of liver cirrhosis in China. The prevalence of liver cirrhosis increased most significantly in the young age group compared with the other age group. Preventive strategies targeting MASLD would be necessary to reduce the disease burden of cirrhosis in China, especially in the young aged generation.

Macrophage neogenin deficiency exacerbates myocardial remodeling and inflammation after acute myocardial infarction through JAK1-STAT1 signaling.

Immune response plays a crucial role in post-myocardial infarction (MI) myocardial remodeling. Neogenin (Neo1), a multifunctional transmembrane receptor, plays a critical role in the immune response; however, whether Neo1 participates in pathological myocardial remodeling after MI is unclear. Our study found that Neo1 expression changed significantly after MI in vivo and after LPS + IFN-γ stimulation in bone marrow-derived macrophages (BMDMs) in vitro. Neo1 functional deficiency (using a neutralizing antibody) and macrophage-specific Neo1 deficiency (induced by Neo1flox/flox;Cx3cr1cre mice) increased infarction size, enhanced cardiac fibrosis and cardiomyocyte apoptosis, and exacerbated left ventricular dysfunction post-MI in mice. Mechanistically, Neo1 deficiency promoted macrophage infiltration into the ischemic myocardium and transformation to a proinflammatory phenotype, subsequently exacerbating the inflammatory response and impairing inflammation resolution post-MI. Neo1 deficiency regulated macrophage phenotype and function, possibly through the JAK1-STAT1 pathway, as confirmed in BMDMs in vitro. Blocking the JAK1-STAT1 pathway with fludarabine phosphate abolished the impact of Neo1 on macrophage phenotype and function, inflammatory response, inflammation resolution, cardiomyocyte apoptosis, cardiac fibrosis, infarction size and cardiac function. In conclusion, Neo1 deficiency aggravates inflammation and left ventricular remodeling post-MI by modulating macrophage phenotypes and functions via the JAK1-STAT1 signaling pathway. These findings highlight the anti-inflammatory potential of Neo1, offering new perspectives for therapeutic targets in MI treatment. Neo1 deficiency aggravated inflammation and left ventricular remodeling after MI by modulating macrophage phenotypes and functions via the JAK1-STAT1 signaling pathway.

Resolvin D2 and its receptor GPR18 in cardiovascular and metabolic diseases: A promising biomarker and therapeutic target.

Accumulating evidence suggests that inflammation plays an important role in the pathophysiology of the initiation and progression of cardiovascular and metabolic diseases (CVMDs). Anti-inflammation strategies and those that promote inflammation resolution have gradually become potential therapeutic approaches for CVMDs. Resolvin D2 (RvD2), a specialized pro-resolving mediator, exerts anti-inflammatory and pro-resolution effects through its receptor GPR18, a G protein-coupled receptor. Recently, the RvD2/GPR18 axis has received more attention due to its protective role in CVMDs, including atherosclerosis, hypertension, ischaemiareperfusion, and diabetes. Here, we introduce basic information about RvD2 and GPR18, summarize their roles in different immune cells, and review the therapeutic potential of the RvD2/GPR18 axis in CVMDs. In summary, RvD2 and its receptor GPR18 play an important role in the occurrence and development of CVMDs and are potential biomarkers and therapeutic targets.

The serial mediating effects of social isolation and resilience on the relationship between fear of dementia and insomnia in community-dwelling older adults.

AIMS: This study aims to explore the correlation between fear of dementia and insomnia among community-dwelling older adults and to examine the mediating roles of social isolation and resilience on this correlation. METHODS: A total of 259 community-dwelling older adults from Mianyang, China were recruited from June 2021 to August 2021 using convenience sampling. The Chinese versions of the Fear of Dementia Scale (FODS), Lubben Social Network Scale (LSNS-6), 25-item Connor-Davidson Resilience Scale (CD-RISC-25) and Athens Insomnia Scale (AIS) were used to collect specific, study-related information from the subjects. Correlations between variables of interest were examined by Pearson analysis, and mediation analysis was conducted to explore the direct, indirect and total effects of the fear of dementia on insomnia vis-à-vis social isolation and resilience. RESULTS: Results from 259 older adults indicated that fear of dementia and insomnia in older adults are positively correlated, that social isolation and resilience mediate the relationship between them, and that social isolation and resilience also had a statistically significant serial mediating effect. CONCLUSION: Fear of dementia is positively related to insomnia in older community-dwelling Chinese adults, but resilience and social support may buffer the negative impact of fear of dementia and improve sleep quality. IMPACT: Fear of dementia is becoming more and more common in community-dwelling older adults in China, and this emotional response to ageing and disease anxiety may be to blame for the poor sleep quality of some ageing populations. However, social support and resilience may buffer the negative impact of fear of dementia. The findings in this study indicate a need for well-trained community nurses and other health practitioners to implement targeted strategies to reduce insomnia among older adults with fear of dementia. These strategies should strengthen resilience as well as social support.

Association of Inpatient Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers With Mortality Among Patients With Hypertension Hospitalized With COVID-19.

RATIONALE: Use of ACEIs (angiotensin-converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers) is a major concern for clinicians treating coronavirus disease 2019 (COVID-19) in patients with hypertension. OBJECTIVE: To determine the association between in-hospital use of ACEI/ARB and all-cause mortality in patients with hypertension and hospitalized due to COVID-19. METHODS AND RESULTS: This retrospective, multi-center study included 1128 adult patients with hypertension diagnosed with COVID-19, including 188 taking ACEI/ARB (ACEI/ARB group; median age 64 [interquartile range, 55-68] years; 53.2% men) and 940 without using ACEI/ARB (non-ACEI/ARB group; median age 64 [interquartile range 57-69]; 53.5% men), who were admitted to 9 hospitals in Hubei Province, China from December 31, 2019 to February 20, 2020. In mixed-effect Cox model treating site as a random effect, after adjusting for age, gender, comorbidities, and in-hospital medications, the detected risk for all-cause mortality was lower in the ACEI/ARB group versus the non-ACEI/ARB group (adjusted hazard ratio, 0.42 [95% CI, 0.19-0.92]; P=0.03). In a propensity score-matched analysis followed by adjusting imbalanced variables in mixed-effect Cox model, the results consistently demonstrated lower risk of COVID-19 mortality in patients who received ACEI/ARB versus those who did not receive ACEI/ARB (adjusted hazard ratio, 0.37 [95% CI, 0.15-0.89]; P=0.03). Further subgroup propensity score-matched analysis indicated that, compared with use of other antihypertensive drugs, ACEI/ARB was also associated with decreased mortality (adjusted hazard ratio, 0.30 [95% CI, 0.12-0.70]; P=0.01) in patients with COVID-19 and coexisting hypertension. CONCLUSIONS: Among hospitalized patients with COVID-19 and coexisting hypertension, inpatient use of ACEI/ARB was associated with lower risk of all-cause mortality compared with ACEI/ARB nonusers. While study interpretation needs to consider the potential for residual confounders, it is unlikely that in-hospital use of ACEI/ARB was associated with an increased mortality risk.

pH-Dependent Chemical Transformations of Humic-Like Substances and Further Cognitions Revealed by Optical Methods.

Humic-like substances (HULIS) are macromolecular complex groups in water-soluble organic compounds (WSOC). pH is a crucial factor that influences the chemical transformations of HULIS in atmospheric particles, but this has been rarely investigated, especially under varying pH conditions. This study attempted to unveil the chemical transformation mechanisms of HULIS under a range of pH conditions using optical methods. The pH-dependent light absorption and fluorescence properties of HULIS were comprehensively analyzed; the acidity coefficient (pKa) of HULIS in relation to chemical structures was determined, and the hypothetical chemical transformation mechanisms of HULIS with increasing pH were analyzed by optical characterizations. The results suggested that pH greatly impacted the light absorption and fluorescence efficiencies of HULIS in both winter and summer seasons, and pKa was an important inflection point. The pKa of HULIS ranged from 3.5 to 8.0 in winter and 6.4 to 10.0 in summer. The acidic/basic groups were identified as -OH or -NH2 substituted quinolines, carboxylic aromatics, and pyridines. The pH-sensitive species accounted for about 6% and 21% of HULIS-C (carbon concentrations of HULIS) in winter and summer, respectively. The varying optical spectra with increasing pH might result from charge transfer or complex reactions with HULIS deprotonation.

The global disease burden attributable to a diet low in fibre in 204 countries and territories from 1990 to 2019.

OBJECTIVE: The relationship of a diet low in fibre with mortality has not been evaluated. This study aims to assess the burden of non-communicable chronic diseases (NCD) attributable to a diet low in fibre globally from 1990 to 2019. DESIGN: All data were from the Global Burden of Disease (GBD) Study 2019, in which the mortality, disability-adjusted life-years (DALY) and years lived with disability (YLD) were estimated with Bayesian geospatial regression using data at global, regional and country level acquired from an extensively systematic review. SETTING: All data sourced from the GBD Study 2019. PARTICIPANTS: All age groups for both sexes. RESULTS: The age-standardised mortality rates (ASMR) declined in most GBD regions; however, in Southern sub-Saharan Africa, the ASMR increased from 4·07 (95 % uncertainty interval (UI) (2·08, 6·34)) to 4·60 (95 % UI (2·59, 6·90)), and in Central sub-Saharan Africa, the ASMR increased from 7·46 (95 % UI (3·64, 11·90)) to 9·34 (95 % UI (4·69, 15·25)). Uptrends were observed in the age-standardised YLD rates attributable to a diet low in fibre in a number of GBD regions. The burden caused by diabetes mellitus increased in Central Asia, Southern sub-Saharan Africa and Eastern Europe. CONCLUSIONS: The burdens of disease attributable to a diet low in fibre in Southern sub-Saharan Africa and Central sub-Saharan Africa and the age-standardised YLD rates in a number of GBD regions increased from 1990 to 2019. Therefore, greater efforts are needed to reduce the disease burden caused by a diet low in fibre.

Global and Regional Trends and Projections of Infective Endocarditis-Associated Disease Burden and Attributable Risk Factors from 1990 to 2030.

Objective To forecast the future burden and its attributable risk factors of infective endocarditis (IE). Method We analyzed the disease burden of IE and its risk factors from 1990 to 2019 using the Global Burden of Disease 2019 database and projected the disease burden from 2020 to 2030 using a Bayesian age-period-cohort model. Results By 2030, the incidence of IE will increase uncontrollably on a global scale, with developed countries having the largest number of cases and developing countries experiencing the fastest growth. The affected population will be predominantly males, but the gender gap will narrow. The elderly in high-income countries will bear the greatest burden, with a gradual shift to middle-income countries. The incidence of IE in countries with middle/high-middle social-demographic indicators (SDI) will surpass that of high SDI countries. In China, the incidence rate and the number of IE will reach 18.07 per 100,000 and 451,596 in 2030, respectively. IE-associated deaths and heart failure will continue to impose a significant burden on society, the burden on women will increase and surpass that on men, and the elderly in high-SDI countries will bear the heaviest burden. High systolic blood pressure has become the primary risk factor for IE-related death. Conclusions This study provides comprehensive analyses of the disease burden and risk factors of IE worldwide over the next decade. The IE-associated incidence will increase in the future and the death and heart failure burden will not be appropriately controlled. Gender, age, regional, and country heterogeneity should be taken seriously to facilitate in making effective strategies for lowering the IE disease burden.

Association Between Lipid Profiles and Left Ventricular Hypertrophy: New Evidence from a Retrospective Study.

Objective To explore the association between lipid profiles and left ventricular hypertrophy in a Chinese general population. Methods We conducted a retrospective observational study to investigate the relationship between lipid markers [including triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL-cholesterol, apolipoprotein A-I, apolipoprotein B, lipoprotein[a], and composite lipid profiles] and left ventricular hypertrophy. A total of 309,400 participants of two populations (one from Beijing and another from nationwide) who underwent physical examinations at different health management centers between 2009 and 2018 in China were included in the cross-sectional study. 7,475 participants who had multiple physical examinations and initially did not have left ventricular hypertrophy constituted a longitudinal cohort to analyze the association between lipid markers and the new-onset of left ventricular hypertrophy. Left ventricular hypertrophy was measured by echocardiography and defined as an end-diastolic thickness of the interventricular septum or left ventricle posterior wall > 11 mm. The Logistic regression model was used in the cross-sectional study. Coxmodel and Coxmodel with restricted cubic splines were used in the longitudinal cohort. Results In the cross-sectional study, for participants in the highest tertile of each lipid marker compared to the respective lowest, triglycerides [odds ratio (OR): 1.250, 95%CI: 1.060 to 1.474], HDL-cholesterol (OR: 0.780, 95%CI: 0.662 to 0.918), and lipoprotein(a) (OR: 1.311, 95%CI: 1.115 to 1.541) had an association with left ventricular hypertrophy. In the longitudinal cohort, for participants in the highest tertile of each lipid marker at the baseline compared to the respective lowest, triglycerides [hazard ratio (HR): 3.277, 95%CI: 1.720 to 6.244], HDL-cholesterol (HR: 0.516, 95%CI: 0.283 to 0.940), non-HDL-cholesterol (HR: 2.309, 95%CI: 1.296 to 4.112), apolipoprotein B (HR: 2.244, 95%CI: 1.251 to 4.032) showed an association with new-onset left ventricular hypertrophy. In the Coxmodel with forward stepwise selection, triglycerides were the only lipid markers entered into the final model. Conclusion Lipids levels, especially triglycerides, are associated with left ventricular hypertrophy. Controlling triglycerides level potentiate to be a strategy in harnessing cardiac remodeling but deserve to be further investigated.

Longitudinal Association Between Markers of Liver Injury and Mortality in COVID-19 in China.

BACKGROUND AND AIMS: Coronavirus disease 2019 (COVID-19) is a new infectious disease. To reveal the hepatic injury related to this disease and its clinical significance, we conducted a multicenter retrospective cohort study that included 5,771 adult patients with COVID-19 pneumonia in Hubei Province. APPROACH AND RESULTS: We reported the distributional and temporal patterns of liver injury indicators in these patients and determined their associated factors and death risk. Longitudinal liver function tests were retrospectively analyzed and correlated with the risk factors and death. Liver injury dynamic patterns differed in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bilirubin (TBIL). AST elevated first, followed by ALT, in severe patients. ALP modestly increased during hospitalization and largely remained in the normal range. The fluctuation in TBIL levels was mild in the non-severe and the severe groups. AST abnormality was associated with the highest mortality risk compared with the other indicators of liver injury during hospitalization. Common factors associated with elevated liver injury indicators were lymphocyte count decrease, neutrophil count increase, and male gender. CONCLUSION: The dynamic patterns of liver injury indicators and their potential risk factors may provide an important explanation for the COVID-19-associated liver injury. Because elevated liver injury indicators, particularly AST, are strongly associated with the mortality risk, our study indicates that these parameters should be monitored during hospitalization.

Source apportionment of VOCs in a typical medium-sized city in North China Plain and implications on control policy.

Characteristics of atmospheric VOCs (volatile organic compounds) have been extensively studied in megacities in China, however, they are scarcely investigated in medium/small-sized cities in North China Plain (NCP). A comprehensive research on possible sources of VOCs was conducted in a medium-sized city of NCP, from May to September 2019. A total of 143 canister samples of 8 sites in Xuchang city were collected, and 57 VOC species were detected. The average VOC concentrations were 42.6 ± 31.6 µg/m3, with 53.7 ± 31.0 µg/m3 and 32.1 ± 27. 8 µg/m3, in the morning and afternoon, respectively. Alkenes and aromatics contributed 80% of the total ozone formation potential (OFP). Aromatics accounted for more than 95% of secondary organic aerosol potential (SOAP). VOCs were dominated by the local emission with significant transport from the southeast direction. PMF analysis extracted 6 sources, which were combustion (33.1%), LPG usage (19.3%), vehicular exhaust & fuel evaporation (15.8%), solvent usage (15.2%), industrial (9.11%) and biogenic (7.51%), respectively and they contributed 33.4%, 17.6%, 12.9%, 18.6%, 9.28% and 8.22% to the OFP, respectively. Combustion and LPG usage were the dominant VOC sources; and combustion, solvent usage and LPG usage were the main sources of OFP in Xuchang city, which were different to megacities in China with a high contribution from vehicular exhaust, solvent usage and industry, suggesting specific control strategies on VOCs need to be implemented in medium-sized city such as Xuchang city.

The Ubiquitin E3 Ligase TRAF6 Exacerbates Ischemic Stroke by Ubiquitinating and Activating Rac1.

Stroke is one of the leading causes of morbidity and mortality worldwide. Inflammation, oxidative stress, apoptosis, and excitotoxicity contribute to neuronal death during ischemic stroke; however, the mechanisms underlying these complicated pathophysiological processes remain to be fully elucidated. Here, we found that the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6) was markedly increased after cerebral ischemia/reperfusion (I/R) in mice. TRAF6 ablation in male mice decreased the infarct volume and neurological deficit scores and decreased proinflammatory signaling, oxidative stress, and neuronal death after cerebral I/R, whereas transgenic overexpression of TRAF6 in male mice exhibited the opposite effects. Mechanistically, we demonstrated that TRAF6 induced Rac1 activation and consequently promoted I/R injury by directly binding and ubiquitinating Rac1. Either functionally mutating the TRAF6 ubiquitination site on Rac1 or inactivating Rac1 with a specific inhibitor reversed the deleterious effects of TRAF6 overexpression during I/R injury. In conclusion, our study demonstrated that TRAF6 is a key promoter of ischemic signaling cascades and neuronal death after cerebral I/R injury. Therefore, the TRAF6/Rac1 pathway might be a promising target to attenuate cerebral I/R injury.SIGNIFICANCE STATEMENT Stroke is one of the most severe and devastating neurological diseases globally. The complicated pathophysiological processes restrict the translation of potential therapeutic targets into medicine. Further elucidating the molecular mechanisms underlying cerebral ischemia/reperfusion injury may open a new window for pharmacological interventions to promote recovery from stroke. Our study revealed that ischemia-induced tumor necrosis factor receptor-associated factor 6 (TRAF6) upregulation binds and ubiquitinates Rac1 directly, which promotes neuron death through neuroinflammation and neuro-oxidative signals. Therefore, precisely targeting the TRAF6-Rac1 axis may provide a novel therapeutic strategy for stroke recovery.

Reduced atherosclerosis lesion size, inflammatory response in miR-150 knockout mice via macrophage effects.

Atherosclerosis is considered to be a chronic inflammatory disease that can lead to severe clinically important cardiovascular events. miR-150 is a small noncoding RNA that significantly enhances inflammatory responses by upregulating endothelial cell proliferation and migration, as well as intravascular environmental homeostasis. However, the exact role of miR-150 in atherosclerosis remains unknown. Here, we investigated the effect of miR-150 deficiency on atherosclerosis development. Using double-knockout (miR-150-/- and ApoE-/-) mice, we measured atherosclerotic lesion size and stability. Meanwhile, we conducted in vivo bone marrow transplantation to identify cellular-level components of the inflammatory response. Compared with mice deficient only in ApoE, the double-knockout mice had significantly smaller atherosclerotic lesions and displayed an attenuated inflammatory response. Moreover, miR-150 ablation promoted plaque stabilization via increases in smooth muscle cell and collagen content and decreased macrophage infiltration and lipid accumulation. The in vitro experiments indicated that an inflammatory response with miR-150 deficiency in atherosclerosis results directly from upregulated expression of the cytoskeletal protein, PDZ and LIM domain 1 (PDLIM1), in macrophages. More importantly, the decreases in phosphorylated p65 expression and inflammatory cytokine secretion induced by miR-150 ablation were reversed by PDLIM1 knockdown. These findings suggest that miR-150 is a promising target for the management of atherosclerosis.

Interferon Regulatory Factor 4 Inhibits Neointima Formation by Engaging Krüppel-Like Factor 4 Signaling.

BACKGROUND: The mechanisms underlying neointima formation remain unclear. Interferon regulatory factors (IRFs), which are key innate immune regulators, play important roles in cardiometabolic diseases. However, the function of IRF4 in arterial restenosis is unknown. METHODS: IRF4 expression was first detected in human and mouse restenotic arteries. Then, the effects of IRF4 on neointima formation were evaluated with universal IRF4-deficient mouse and rat carotid artery injury models. We performed immunostaining to identify IRF4-expressing cells in the lesions. Smooth muscle cell (SMC)-specific IRF4-knockout (KO) and -transgenic (TG) mice were generated to evaluate the effects of SMC-IRF4 on neointima formation. We used microarray, bioinformatics analysis, and chromatin immunoprecipitation assay to identify the downstream signals of IRF4 and to verify the targets in vitro. We compared SMC-IRF4-KO/Krüppel-like factor 4 (KLF4)-TG mice with SMC-IRF4-KO mice and SMC-specific IRF4-TG/KLF4-KO mice with SMC-specific IRF4-TG mice to investigate whether the effect of IRF4 on neointima formation is KLF4-dependent. The effect of IRF4 on SMC phenotype switching was also evaluated. RESULTS: IRF4 expression in both the human and mouse restenotic arteries is eventually downregulated. Universal IRF4 ablation potentiates neointima formation in both mice and rats. Immunostaining indicated that IRF4 was expressed primarily in SMCs in restenotic arteries. After injury, SMC-IRF4-KO mice developed a thicker neointima than control mice. This change was accompanied by increased SMC proliferation and migration. However, SMC-specific IRF4-TG mice exhibited the opposite phenotype, demonstrating that IRF4 exerts protective effects against neointima formation. The mechanistic study indicated that IRF4 promotes KLF4 expression by directly binding to its promoter. Genetic overexpression of KLF4 in SMCs largely reversed the neointima-promoting effect of IRF4 ablation, whereas ablation of KLF4 abolished the protective function of IRF4, indicating that the protective effects of IRF4 against neointima formation are KLF4-dependent. In addition, IRF4 promoted SMC dedifferentiation. CONCLUSIONS: IRF4 protects arteries against neointima formation by promoting the expression of KLF4 by directly binding to its promoter. Our findings suggest that this previously undiscovered IRF4-KLF4 axis plays a key role in vasculoproliferative pathology and may be a promising therapeutic target for the treatment of arterial restenosis.

Caspase recruitment domain 6 protects against hepatic ischemia/reperfusion injury by suppressing ASK1.

BACKGROUND & AIMS: The hepatic injury caused by ischemia/reperfusion (I/R) insult is predominantly determined by the complex interplay of sterile inflammation and liver cell death. Caspase recruitment domain family member 6 (CARD6) was initially shown to play important roles in NF-κB activation. In our preliminary studies, CARD6 downregulation was closely related to hepatic I/R injury in liver transplantation patients and mouse models. Thus, we hypothesized that CARD6 protects against hepatic I/R injury and investigated the underlying molecular mechanisms. METHODS: A partial hepatic I/R operation was performed in hepatocyte-specific Card6 knockout mice (HKO), Card6 transgenic mice with CARD6 overexpression specifically in hepatocytes (HTG), and the corresponding control mice. Hepatic histology, serum aminotransferases, inflammatory cytokines/chemokines, cell death, and inflammatory signaling were examined to assess liver damage. The molecular mechanisms of CARD6 function were explored in vivo and in vitro. RESULTS: Liver injury was alleviated in Card6-HTG mice compared with control mice as shown by decreased cell death, lower serum aminotransferase levels, and reduced inflammation and infiltration, whereas Card6-HKO mice had the opposite phenotype. Mechanistically, phosphorylation of ASK1 and its downstream effectors JNK and p38 were increased in the livers of Card6-HKO mice but repressed in those of Card6-HTG mice. Furthermore, ASK1 knockdown normalized the effect of CARD6 deficiency on the activation of NF-κB, JNK and p38, while ASK1 overexpression abrogated the suppressive effect of CARD6. CARD6 was also shown to interact with ASK1. Mutant CARD6 that lacked the ability to interact with ASK1 could not inhibit ASK1 and failed to protect against hepatic I/R injury. CONCLUSIONS: CARD6 is a novel protective factor against hepatic I/R injury that suppresses inflammation and liver cell death by inhibiting the ASK1 signaling pathway. LAY SUMMARY: The protein CARD6 plays an important role during the process of liver blood flow restriction (ischemia) and restoration (reperfusion). By suppressing the activity of ASK1, CARD6 can protect against hepatocyte injury. Targeting CARD6 is a potential strategy for prevention and treatment of ischemia/reperfusion injury.

Mindin deficiency in macrophages protects against foam cell formation and atherosclerosis by targeting LXR-ß.

Mindin, which is a highly conserved extracellular matrix protein, has been documented to play pivotal roles in regulating angiogenesis, inflammatory processes, and immune responses. The aim of the present study was to assess whether mindin contributes to the development of atherosclerosis. A significant up-regulation of Mindin expression was observed in the serum, arteries and atheromatous plaques of ApoE-/- mice after high-fat diet treatment. Mindin-/-ApoE-/- mice and macrophage-specific mindin overexpression in ApoE-/- mice (Lyz2-mindin-TG) were generated to evaluate the effect of mindin on the development of atherosclerosis. The Mindin-/-ApoE-/- mice exhibited significantly ameliorated atherosclerotic burdens in the entire aorta and aortic root and increased atherosclerotic plaque stability. Moreover, bone marrow transplantation further demonstrated that mindin deficiency in macrophages was largely responsible for the alleviated atherogenesis. The Lyz2-mindin-TG mice exhibited the opposite phenotype. Mindin deficiency enhanced foam cell formation by increasing the expression of cholesterol effectors, including ABCA1 and ABCG1. The mechanistic study indicated that mindin ablation promoted LXR-ß expression via a direct interaction. Importantly, LXR-ß inhibition largely reversed the ameliorating effect of mindin deficiency on foam cell formation and ABCA1 and ABCG1 expression. The present study demonstrated that mindin deficiency serves as a novel mediator that protects against foam cell formation and atherosclerosis by directly interacting with LXR-ß.

Oncostatin M receptor ß deficiency attenuates atherogenesis by inhibiting JAK2/STAT3 signaling in macrophages.

Oncostatin M (OSM) is a secreted cytokine mainly involved in chronic inflammatory and cardiovascular diseases through binding to OSM receptor ß (OSMR-ß). Recent studies demonstrated that the presence of OSM contributed to the destabilization of atherosclerotic plaque. To investigate whether OSMR-ß deficiency affects atherosclerosis, male OSMR-ß-/-ApoE-/- mice were generated and utilized. Here we observed that OSMR-ß expression was remarkably upregulated in both human and mouse atherosclerotic lesions, which were mainly located in macrophages. We found that OSMR-ß deficiency significantly ameliorated atherosclerotic burden in aorta and aortic root relative to ApoE-deficient littermates and enhanced the stability of atherosclerotic plaques by increasing collagen and smooth muscle cell content, while decreasing macrophage infiltration and lipid accumulation. Moreover, bone marrow transplantation of OSMR-ß-/- hematopoietic cells to atherosclerosis-prone mice displayed a consistent phenotype. Additionally, we observed a relatively reduced level of JAK2 and signal transducer and activator of transcription (STAT)3 in vivo and under Ox-LDL stimulation in vitro. Our findings suggest that OSMR-ß deficiency in macrophages improved high-fat diet-induced atherogenesis and plaque vulnerability. Mech-anistically, the protective effect of OSMR-ß deficiency on atherosclerosis may be partially attributed to the inhibition of the JAK2/STAT3 activation in macrophages, whereas OSM stimulation can activate the signaling pathway.

Hepatic Oncostatin M Receptor ß Regulates Obesity-Induced Steatosis and Insulin Resistance.

The liver is an essential insulin-responsive organ that is critical for maintaining glucose homeostasis and lipid metabolism. Oncostatin M receptor ß chain (OSMRß) is implicated in adipose tissue- and immune cell-mediated metabolic regulation. However, the role of hepatocyte-derived OSMRß in metabolic disorders remains unclear. Here, we report on the central role of OSMRß in the protection against obesity and deregulation of glucose and lipids. We observed significantly varied expression levels of OSMRß in hepatic tissues in both human samples and mouse models of nonalcoholic fatty liver disease. Mice lacking either whole-body or hepatic OSMRß displayed exacerbated diet-induced insulin resistance, hepatic steatosis, and inflammation, both in diet-induced and genetically (ob/ob) obese mice. These adverse effects were markedly attenuated by hepatocyte-specific overexpression of OSMRß. Mechanistically, we showed that OSMRß phosphorylates and activates the Janus kinase 2 (JAK2)/STAT3 signaling pathway in the liver. More importantly, the liver-restricted overexpression of STAT3 rescued glucose tolerance and ameliorated hepatic steatosis and inflammation in OSMRß knockout mice, whereas OSMRß overexpression failed to protect against hepatic steatosis, insulin resistance, and hepatic inflammation in STAT3-deficient mice. Thus, activation of STAT3 is both sufficient and required to produce OSMRß-mediated beneficial effects. In conclusion, hepatic OSMRß expression alleviates obesity-induced hepatic insulin resistance and steatosis through the activation of JAK2/STAT3 signaling cascades.