👤 James K C Lui

N6-methyladenosine (m6A) RNA modification can govern cell fate by co- or post-transcriptionally regulating gene expression. VSMCs can undergo phenotypic switching, contributing to other cells within atherosclerotic plaques, including foam cell- and macrophage-like cells. However, the role of VSMC m6A in atherosclerosis development remains unclear. While PPAR-α and PPAR-γ have been extensively studied in macrophages for their roles in atherosclerosis, the epigenetic regulation of these nuclear receptors under high cholesterol conditions remains poorly understood. We utilized murine and human atherosclerotic aortas, along with VSMC-specific Mettl3 and Mettl14 knockout mice, to evaluate the role of VSMC m6A in atherosclerosis. Lineage tracing was used to assess macrophage-like VSMCs. The epigenetic regulation of Ppara and Pparg transcription by Methyltransferase-like 14 (METTL14) was investigated through a variety of methods, including histological, cellular, genomic, transcriptomic, metabolomic, lipidomic, computational, and pharmacological approaches. The therapeutic potential of VSMC Mettl14 in atherosclerosis was analyzed using adeno-associated virus-mediated expression in ApoE-/- mice.We showed that the METTL3/METTL14 methyltransferase complex was reduced in both murine and human atherosclerotic VSMCs. The levels of METTL3, and consequently m6A, were regulated by METTL14, which was in turn influenced by ox-LDL. Notably, while VSMC METTL3 or m6A did not contribute to atherosclerosis, VSMC-specific Mettl14 knockout mice exhibited accelerated foam cell formation, enhanced vascular inflammation, and exacerbated atherosclerosis. These effects were driven by impaired beta-oxidation and reduced mitochondrial oxidative phosphorylation (OXPHOS). Replenishment of Mettl14 significantly attenuated these adverse effects. Specifically, METTL14 regulated phenotypic switching of VSMCs and modulated the number of VSMC-derived macrophage-like cells, rather than infiltrating macrophages, within atherosclerotic plaques. Furthermore, we demonstrated that METTL14 regulates the transcription of Ppara and Pparg, master regulators of lipid metabolism that promote cholesterol efflux, by enhancing SETD1A-mediated H3K4 trimethylation in an m6A-independent manner. Activation of PPAR-γ with rosiglitazone restored impaired mitochondrial OXPHOS in Mettl14-deficient VSMCs, leading to reduced lipid accumulation. Lastly, recapitulating Mettl14 expression in atherosclerotic vessels through AAV gene therapy effectively inhibited atherosclerosis progression without compromising liver function. We have unveiled that METTL14 promotes lipid metabolism and inhibits atherogenesis through activating PPAR-α/γ expression. These experiments highlight the therapeutic potential of the endogenous METTL14/PPAR-α/γ axis for treating atherosclerotic and metabolic diseases. Show less

Diabetes-related chronic kidney disease (DKD) is a leading cause of end-stage kidney disease (ESKD), requiring costly dialysis or kidney transplantation. Existing standard- of-care tests for DKD have several limitations, and an alternative is Promarker®D, a validated plasma biomarker test system that predicts DKD in adults with diabetes up to 4 years before symptoms develop. To enable high-throughput application of PromarkerD, a novel CaptSureTM immunoassay version of the test was developed targeting plasma biomarkers Apolipoprotein A4 (ApoA4) and CD5 antigen-like (CD5L). The analytical performance of the assay was assessed, and clinical samples from 2 independent clinical cohorts (>1700 adults with type 2 diabetes [T2D]) were used for the development and external validation of the DKD predictive test. The PromarkerD test system combined ApoA4 and CD5L concentrations with clinical factors age and estimated glomerular filtration rate (eGFR) to calculate risk scores (0% to 100%) and classify study participants as either at low, moderate, or high risk for future kidney decline. PromarkerD demonstrated reliable analytical performance and provided a high discriminative capability in adults with T2D (receiver operating characteristic area under the curve [ROC-AUC]: 0.78 to 0.88) to predict 4-year kidney decline, defined as incident DKD (eGFR <60 mL/min/1.73 m2) or eGFR decline ≥40%, with sensitivity of 75.8% to 85.1% at the moderate-risk cutoff and specificity of >92% at the high-risk cutoff across the two cohorts. The next-generation PromarkerD test system offers a convenient yet highly effective tool for DKD risk assessment. By introducing PromarkerD to standard diabetes care, preventative treatment strategies may be implemented early before permanent kidney function loss occurs. Show less

Second-generation antipsychotics (SGAs) are widely used to treat schizophrenia (SCZ), but they often induce metabolic side effects like dyslipidemia and obesity. We conducted genome-wide association studies (GWASs) to identify genetic variants associated with SGA-induced lipid and BMI changes in Chinese SCZ patients. A longitudinal cohort of Chinese SCZ receiving SGAs was followed for up to 18.7 years (mean = 5.7 years, SD = 3.3 years). We analysed the patients' genotypes (N = 669), lipid profiles, and BMI using 19 316 prescription records and 3 917 to 7 596 metabolic measurements per outcome. Linear mixed models were employed to evaluate seven SGAs' random effects on metabolic changes for each patient, followed by GWAS and gene set analyses with Bonferroni and FDR correction. Five SNPs achieved p-value < 5 × 10 Show less

Resistance and resilience are pathways through which modifiable behaviors may reduce Alzheimer's disease (AD) risk. Sleep - a known modifiable factor - is understudied in this context, especially among older women at elevated risk for AD. Forty-five functionally intact older women (≥65 years) at heightened risk for AD completed wrist actigraphy to capture average nocturnal sleep duration. Tau positron emission tomography imaging ( Shorter sleep duration amplified the association between APOE ε4 status and tau, while longer sleep mitigated it. Similarly, tau burden was related to worse memory performance only among those with short sleep duration. Longer sleep duration may promote resistance and resilience to AD in at-risk older women, highlighting sleep as a critical intervention target. Sleep was measured via wrist actigraphy, tau via PET imaging, and memory with a composite score. Longer sleep attenuated the link between APOE ε4 carriership and tau PET across Braak regions. Greater sleep duration weakened the negative impact of tau on memory performance. This is the first study to examine sleep in AD resistance and resilience among older women at heightened risk. Show less

Tetralogy of Fallot (TOF) is the most common cyanotic heart defect in neonates. While there is compelling evidence of genetic contribution to the etiology of TOF, the contribution of noncoding variants to the development of the defect remains unexplored. Potentially damaging noncoding de novo variants (NC DNVs) were detected from 141 Chinese nonsyndromic TOF trios (CHN-TOF) and compared with those detected in the Pediatric Cardiac Genomics Consortium (PCGC). Bioinformatic analyses on noncoding and previously detected coding DNVs were performed to identify developmental pathways affected in TOF. Chinese but not PCGC-TOF patients showed a notably increased burden of putative damaging NC DNVs (n = 249). In Chinese, NC and coding DNVs were predominantly associated with cardiomyocyte differentiation and with chamber/valve/aorta development, respectively, producing a combined enrichment in NOTCH signaling (p = 1.1 × 10 Show less

The KIT/c-KIT proto-oncogene is frequently over-expressed in Merkel cell carcinoma (MCC), an aggressive skin cancer commonly caused by Merkel cell polyomavirus (MCPyV). Here, we demonstrated that truncated MCPyV-encoded large T-antigen (LT) suppressed macroautophagy/autophagy by stabilizing and sequestering KIT in the paranuclear compartment via binding VPS39. KIT engaged with phosphorylated BECN1, thereby enhancing its association with BCL2 while diminishing its interaction with the PIK3C3 complex. This process ultimately resulted in the suppression of autophagy. Depletion of KIT triggered both autophagy and apoptosis, and decreased LT expression. Conversely, blocking autophagy in KIT-depleted cells restored LT levels and rescued apoptosis. Additionally, stimulating autophagy efficiently increased cell death and inhibited tumor growth of MCC xenografts in mice. These insights into the interplay between MCPyV LT and autophagy regulation reveal important mechanisms by which viral oncoproteins are essential for MCC cell viability. Thus, autophagy-inducing agents represent a therapeutic strategy in advanced MCPyV-associated MCC. Show less

Cannabinoids are reported to have neuroprotective properties and play a role in neurogenesis and neuroplasticity in in vitro and in vivo models. Cannabinol (CBN) is a minor cannabinoid produced by the degradation of Δ Show less

The coronavirus disease 2019 (COVID-19) pandemic has caused extensive disruption of public health worldwide. There were reports of COVID-19 patients having multiple complications. This study investigated COVID-19 from a genetic perspective. We conducted RNA sequencing (RNA-Seq) analysis of respiratory tract samples from 24 patients with COVID-19. Eight patients receiving mechanical ventilation or extracorporeal membrane oxygenation were regarded as severe cases; the remaining 16 patients were regarded as non-severe cases. After quality control, statistical analyses were performed by logistic regression and the Kolmogorov-Smirnov test to identify genes associated with disease severity. Six genes were associated with COVID-19 severity in both statistical tests, namely RNA sequencing analysis showed that severe acute respiratory syndrome coronavirus 2 infection is associated with the overexpression of genes involved in nervous system disorders. Show less

Impaired function of gonadotropin-releasing hormone (GnRH) neurons can cause a phenotypic spectrum ranging from delayed puberty to isolated hypogonadotropic hypogonadism (IHH). We sought to identify a new genetic etiology for these conditions. Exome sequencing was performed in an extended family with autosomal dominant, markedly delayed puberty. The effects of the variant were studied in a GnRH neuronal cell line. Variants in the same gene were sought in a large cohort of individuals with IHH. We identified a rare missense variant (F900V) in DLG2 (which encodes PSD-93) that cosegregated with the delayed puberty. The variant decreased GnRH expression in vitro. PSD-93 is an anchoring protein of NMDA receptors, a type of glutamate receptor that has been implicated in the control of puberty in laboratory animals. The F900V variant impaired the interaction between PSD-93 and a known binding partner, Fyn, which phosphorylates NMDA receptors. Variants in DLG2 that also decreased GnRH expression were identified in three unrelated families with IHH. The findings indicate that variants in DLG2/PSD-93 cause autosomal dominant delayed puberty and may also contribute to IHH. The findings also suggest that the pathogenesis involves impaired NMDA receptor signaling and consequently decreased GnRH secretion. Show less

Electrospun fibrous matrices, mimicking extracellular matrix (ECM) hierarchical structures, are potential scaffolds for wound healing. To design functional scaffolds, it is important to explore the interactions between scaffold topographic features and cellular responses, especially directional migration and phenotypic changes, which are critical functional aspects during wound healing. Here, accelerated and persistent migration of human dermal fibroblasts (HDFs) is observed on fibers with aligned orientation. Furthermore, aligned fibers can induce fibroblast-to-myofibroblast differentiation of HDFs. During wound healing, the presence of myofibroblasts advances wound repair by rendering contractile force and ECM deposition within the early and middle courses, but its continuous persistence in the later event may not be desired due to the contribution in pathological scarring. To tune the balance, it is noted in this work that the introduction of matricellular protein angiopoietin-like 4 (ANGPTL4) is capable of reversing the phenotypic alteration induced by aligned fibers, in a time-dependent manner. These results indicate fibrous matrices with oriented configuration are functional in mediating directional cell migration and phenotypic change. The discoveries further suggest that tissue-engineered fibrous grafts with precise alignment modulation and ANGPTL4 releasing properties may thus be promising to promote wound repair with minimizing scar formation. Show less