👤 Kaini Hang

Hypertriglyceridemia (HTG) is a heterogeneous metabolic disorder driven by both genetic susceptibility and secondary factors. Most cases of severe HTG (triglyceride [TG] >10 mmol/L [>885 mg/dL]) have multifactorial chylomicronemia syndrome (MCS) while only a few have familial chylomicronemia syndrome (FCS), a rare autosomal recessive condition. We summarize the pathophysiology of severe HTG, emphasizing impaired intravascular lipolysis of TG-rich lipoproteins and the regulatory role of apolipoproteins (apo), particularly apo C-III. We outline features that distinguish FCS from MCS and discuss diagnostic strategies, including clinical scoring systems and targeted genetic testing. Current management approaches, including responses to conventional TG-lowering therapies and emerging biologic therapies targeting apo C-III, are examined. We searched PubMed for all English language literature focusing on the search terms 'chylomicronemia,' 'familial chylomicronemia syndrome,' 'multifactorial chylomicronemia syndrome,' 'hypertriglyceridemia,' 'APOC3 inhibition,' 'antisense oligonucleotides,' and 'apolipoprotein C-III.' Differentiating FCS from MCS is critical because RNA-based inhibition of apo C-III has transformed the therapeutic landscape for FCS patients. These agents provide substantial, durable TG lowering and meaningful reductions in pancreatitis risk, although cardiovascular benefit remains uncertain. Future efforts should focus on optimizing diagnostic pathways, assessing cardiovascular outcomes, and determining long-term safety of novel biologic therapies. Show less

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder marked by severe hypertriglyceridemia and characteristic clinical manifestations, particularly acute pancreatitis. Conventional triglyceride-lowering therapy is largely ineffective. Apolipoprotein (apo) C-III has emerged as a key therapeutic target to lower triglycerides in FCS. This review compares FCS with more common multifactorial chylomicronemia. We searched PubMed for all English language literature focusing on the search terms 'chylomicronemia,' 'hypertriglyceridemia,' 'APOC3 inhibition,' 'plozasiran,' 'olezarsen,' and 'volanesorsen.' We outline traditional management strategies and their limited role in FCS and explore non-traditional therapies including orlistat, lomitapide, inhibitors of angiopoietin like protein 3 (ANGPTL3), and analogues of fibroblast growth factor 21 (FGF21). The primary focus is on RNA-based gene silencing therapeutics that target apo C-III, particularly the small interfering RNA plozasiran and the allele specific oligonucleotides volanesorsen and olezarsen, highlighting key differences in efficacy and tolerability. In a phase 3 trial of plozasiran, at 10 months, median placebo-adjusted reductions in apo C-III were approximately -90%, while TG levels were reduced up to -59%. Thus, plozasiran and alternative RNA-based therapeutics directed against APOC3 represent transformational therapies for patients with FCS and related phenotypes characterized by severe recalcitrant hypertriglyceridemia. Show less

Aging and age-related diseases share convergent pathways at the proteome level. Here, using plasma proteomics and machine learning, we developed organismal and ten organ-specific aging clocks in the UK Biobank (n = 43,616) and validated their high accuracy in cohorts from China (n = 3,977) and the USA (n = 800; cross-cohort r = 0.98 and 0.93). Accelerated organ aging predicted disease onset, progression and mortality beyond clinical and genetic risk factors, with brain aging being most strongly linked to mortality. Organ aging reflected both genetic and environmental determinants: brain aging was associated with lifestyle, the GABBR1 and ECM1 genes, and brain structure. Distinct organ-specific pathogenic pathways were identified, with the brain and artery clocks linking synaptic loss, vascular dysfunction and glial activation to cognitive decline and dementia. The brain aging clock further stratified Alzheimer's disease risk across APOE haplotypes, and a super-youthful brain appears to confer resilience to APOE4. Together, proteomic organ aging clocks provide a biologically interpretable framework for tracking aging and disease risk across diverse populations. Show less

A comprehensive computational strategy that combined QSAR modelling, molecular docking, and ADMET analysis was used to discover potential inhibitors for β-secretase 1 (BACE-1). A dataset of 1,138 compounds with established BACE-1 inhibitory activities was used to build a QSAR model using mol2vec descriptors and support vector regression. The obtained model demonstrated strong predictive performance (training set: Show less

Multifocal papillary thyroid carcinomas (PTCs) are common and the majority of the tumors harbor mutual BRAF p.V600E mutation. This study aimed to investigate a contemporary series of multifocal PTCs with discordant molecular drivers. Consecutive thyroidectomies diagnosed with multifocal PTCs ≥0.5 cm between 2019 and 2023 were reviewed. Immunohistochemistry (IHC) for BRAF VE1 was performed for all tumors. Cases with discordant BRAF IHC results or morphologic discrepancy were identified, and BRAF IHC-negative tumors were subjected to RAS Q61R IHC and/or targeted RNA next-generation sequencing. A total of 770 patients with a main PTC ≥0.5 cm were identified; 255 (33.1%) had multifocal disease, and 142 (18.4%) had at least another PTC ≥0.5 cm. Among them, 13 cases (9.2%, 13/142) had discordant molecular drivers. Twelve cases had one or more BRAF -positive PTCs accompanied by a BRAF -negative PTC (3 with CCDC6::RET fusion, 1 with NCOA4::RET fusion, 1 with ACBD5::RET fusion, 2 with ETV6::NTRK3 fusion, 1 with TG::FGFR1 fusion, 1 with LMTK2::BRAF fusion, 1 with AGK::BRAF fusion and RAS p.Q61R mutation, 1 with RAS p.Q61R mutation, and 1 without detectable molecular drivers). The last case had tumors with discordant fusion drivers ( VIM::NTRK3 and TNS1::BRAF ). Most cases showed tumors that were morphologically distinct (92.3%, 12/13) and occurred in the contralateral lobes (76.9%, 10/13). Notably, we identified 4 cases (30.8%) that presented as collision tumors and 6 cases (46.2%) that showed lymph node metastases, including 2 with simultaneous involvement by tumors with discordant molecular drivers, as novel findings. In summary, a subset (9.2%) of multifocal PTCs had discordant molecular drivers and 84.6% of them were a combination of BRAF -positive and kinase gene fusion-associated PTCs, most with distinct morphologies. Almost half of the cases had nodal metastasis and a third of them showed simultaneous involvement by tumors with discordant molecular drivers. The results highlight the clinical importance of identifying such cases, given the potentially different treatments. Show less

Glucose-dependent insulinotropic polypeptide receptor (GIPR) is a potential drug target for metabolic disorders. It works with glucagon-like peptide-1 receptor and glucagon receptor in humans to maintain glucose homeostasis. Unlike the other two receptors, GIPR has at least 13 reported splice variants (SVs), more than half of which have sequence variations at either C or N terminus. To explore their roles in endogenous peptide-mediated GIPR signaling, we determined the cryoelectron microscopy (cryo-EM) structures of the two N terminus-altered SVs (referred as GIPR-202 and GIPR-209 in the Ensembl database, SV1 and SV2 here, respectively) and investigated the outcome of coexpressing each of them in question with GIPR in HEK293T cells with respect to ligand binding, receptor expression, cAMP (adenosine 3,5-cyclic monophosphate) accumulation, β-arrestin recruitment, and cell surface localization. It was found that while both N terminus-altered SVs of GIPR neither bound to the hormone nor elicited signal transduction per se, they suppressed ligand binding and cAMP accumulation of GIPR. Meanwhile, SV1 reduced GIPR-mediated β-arrestin 2 responses. The cryo-EM structures of SV1 and SV2 showed that they reorganized the extracellular halves of transmembrane helices 1, 6, and 7 and extracellular loops 2 and 3 to adopt a ligand-binding pocket-occupied conformation, thereby losing binding ability to the peptide. The results suggest a form of signal bias that is constitutive and ligand-independent, thus expanding our knowledge of biased signaling beyond pharmacological manipulation (i.e., ligand specific) as well as constitutive and ligand-independent (e.g., SV1 of the growth hormone-releasing hormone receptor). Show less

Most studies for comprehensive molecular profiling of papillary thyroid carcinoma (PTC) have been performed before the 2017 World Health Organization (WHO) classification, in which the diagnostic criteria of follicular variants of PTC have been modified and noninvasive follicular thyroid neoplasm with papillary-like nuclear features has been introduced. This study aims to investigate the shift in the incidence of BRAF V600E mutations in PTCs following the 2017 WHO classification and to further characterize the histologic subtypes and molecular drivers in BRAF-negative cases. The study cohort consisted of 554 consecutive PTCs larger than 0.5 cm between January 2019 and May 2022. Immunohistochemistry for BRAF VE1 was performed for all cases. Compared with a historical cohort of 509 PTCs from November 2013 to April 2018, the incidence of BRAF V600E mutations was significantly higher in the study cohort (86.8% vs 78.8%, P = .0006). Targeted RNA-based next-generation sequencing using a FusionPlex Pan Solid Tumor v2 panel (ArcherDX) was performed for BRAF-negative PTCs from the study cohort. Eight cribriform-morular thyroid carcinomas and 3 cases with suboptimal RNA quality were excluded from next-generation sequencing. A total of 62 BRAF-negative PTCs were successfully sequenced, including 19 classic follicular predominant PTCs, 16 classic PTCs, 14 infiltrative follicular PTCs, 7 encapsulated follicular PTCs, 3 diffuse sclerosing PTCs, 1 tall cell PTC, 1 solid PTC, and 1 diffuse follicular PTC. Among them, RET fusions were identified in 25 cases, NTRK3 fusions in 13 cases, BRAF fusions in 5 cases including a novel TNS1::BRAF fusion, NRAS Q61R mutations in 3 cases, KRAS Q61K mutations in 2 cases, NTRK1 fusions in 2 cases, an ALK fusion in 1 case, an FGFR1 fusion in 1 case, and an HRAS Q61R mutation in 1 case. No genetic variants, from our commercially employed assay, were detected in the remaining 9 cases. In summary, the incidence of BRAF V600E mutations in PTCs significantly increased from 78.8% to 86.8% in our post-2017 WHO classification cohort. RAS mutations accounted for only 1.1% of the cases. Driver gene fusions were identified in 8.5% of PTCs and were clinically relevant given the emerging targeted kinase inhibitor therapy. Of the 1.6% of cases for which no driver alteration was detected, the specificity of drivers tested and tumor classification require further investigation. Show less

Variants in myosin-binding protein C3 (MYBPC3) gene are a main cause of hypertrophic cardiomyopathy (HCM), accounting for 30% to 40% of the total number of HCM mutations. Gene editing represents a potential permanent cure for HCM. The aim of this study was to investigate whether genome editing of MYBPC3 using the CRISPR/Cas9 system in vivo could rescue the phenotype of rats with HCM. We generated a rat model of HCM ("1098hom") that carried an Mybpc3 premature termination codon mutation (p.W1098x) discovered in a human HCM pedigree. On postnatal day 3, the CRISPR/Cas9 system was introduced into rat pups by a single dose of AAV9 particles to correct the variant using homology-directed repair (HDR). Analysis was performed 6 months after AAV9 injection. The 1098hom rats didn't express MYBPC3 protein and developed an HCM phenotype with increased ventricular wall thickness and diminished cardiac function. Importantly, CRISPR HDR genome editing corrected 3.56% of total mutations, restored MYBPC3 protein expression by 2.12%, and normalized the HCM phenotype of 1098hom rats. Our work demonstrates that the HDR strategy is a promising approach for treating HCM associated with MYBPC3 mutation, and that CRISPR technology has great potential for treating hereditary heart diseases. Show less

Glucose homeostasis, regulated by glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon (GCG) is critical to human health. Several multi-targeting agonists at GIPR, GLP-1R or GCGR, developed to maximize metabolic benefits with reduced side-effects, are in clinical trials to treat type 2 diabetes and obesity. To elucidate the molecular mechanisms by which tirzepatide, a GIPR/GLP-1R dual agonist, and peptide 20, a GIPR/GLP-1R/GCGR triagonist, manifest their multiplexed pharmacological actions over monoagonists such as semaglutide, we determine cryo-electron microscopy structures of tirzepatide-bound GIPR and GLP-1R as well as peptide 20-bound GIPR, GLP-1R and GCGR. The structures reveal both common and unique features for the dual and triple agonism by illustrating key interactions of clinical relevance at the near-atomic level. Retention of glucagon function is required to achieve such an advantage over GLP-1 monotherapy. Our findings provide valuable insights into the structural basis of functional versatility of tirzepatide and peptide 20. Show less

Heat stress resulting from global warming is a serious threat to livestock and humans and can cause impaired metabolism, dysregulated immune functions, and even death. Liver transcriptome of the heat-stressed rabbits supplemented with oral Moringa oleifera leaf powder (MOLP) was performed with the hypothesis that antioxidative properties of MOLP might help to maintain homeostasis under heat stress environment. A total of 21 rabbits were divided into 3 groups (n = 7/group); control (CON, 25°C), heat stress (HS, 35°C for 7 hours daily), and HS supplemented with MOLP (HSM, 35°C) at 200 mg/kg body weight daily for 28 days. Serum analysis indicated that dietary MOLP (HSM) reduced glucose, total cholesterol, triglycerides, and low-density lipoprotein cholesterol contents compared with the HS group (P < .05). The HS group showed increased mRNA expression of interleukin (IL)-1α and IL-1β (P < .05), whereas enhanced expression of Nrf2 was observed in HSM compared with the HS group indicates antioxidative capacity of MOLP. Up-regulated genes PCK1 and ANGPTL4 as indicated by transcriptome analysis can explain increased serum glucose and lipid levels in the HS group. Up-regulation of antiapoptotic gene BCL2A1 by MOLP may suggest protection from heat stress induced apoptosis. In HSM, the up-regulated IL-6 family genes dictate their importance for immune and survival response, whereas genes PIK3R5 and TLR-2 are vital in thermo-tolerance. Further, identification of marker genes elucidates stress regulation response. In conclusion, findings of current study reveal beneficial aspects of dietary MOLP on liver function in heat-stressed rabbits. Show less

Glucose-dependent insulinotropic polypeptide (GIP) is a peptide hormone that exerts crucial metabolic functions by binding and activating its cognate receptor, GIPR. As an important therapeutic target, GIPR has been subjected to intensive structural studies without success. Here, we report the cryo-EM structure of the human GIPR in complex with GIP and a G Show less

SNAI1, an epithelial-mesenchymal transition (EMT)-inducing transcription factor, promotes tumor metastasis and resistance to apoptosis and chemotherapy. SNAI1 protein levels are tightly regulated by proteolytic ubiquitination. Here, we identified USP37 as a SNAI1 deubiquitinase that removes the polyubiquitination chain from SNAI1 and prevents its proteasomal degradation. USP37 directly binds, deubiquitinates, and stabilizes SNAI1. Overexpression of wild-type USP37, but not its catalytically inactive mutant C350S, promotes cancer cell migration. Importantly, depletion of USP37 downregulates endogenous SNAI1 protein and suppresses cell migration, which can be reversed by re-expression of SNAI1. Taken together, our findings suggest that USP37 is a SNAI1 deubiquitinase and a potential therapeutic target to inhibit tumor metastasis. Show less

Wnt/β-catenin signaling is critically involved in metazoan development, stem cell maintenance and human disease. Using Xenopus laevis egg extract to screen for compounds that both stabilize Axin and promote β-catenin turnover, we identified an FDA-approved drug, pyrvinium, as a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). We show pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. CK1α knockdown abrogates the effects of pyrvinium on the Wnt pathway. In addition to its effects on Axin and β-catenin levels, pyrvinium promotes degradation of Pygopus, a Wnt transcriptional component. Pyrvinium treatment of colon cancer cells with mutation of the gene for adenomatous polyposis coli (APC) or β-catenin inhibits both Wnt signaling and proliferation. Our findings reveal allosteric activation of CK1α as an effective mechanism to inhibit Wnt signaling and highlight a new strategy for targeted therapeutics directed against the Wnt pathway. Show less