Munichandra Babu Tirumalasetty

Objective: To identify clinical and genetic factors associated with variation in glycemic response to glucagon-like peptide-1 receptor agonist (GLP-1RA) therapy among adults with type 2 diabetes, with a focus on common GLP1R variations, polygenic risk load, and pancreas-specific regulation annotation. Research Design and Methods: We conducted a retrospective cohort study using electronic health record (EHR)-linked biobank data from the All of Us research workbench platform that included 5784 adults with type 2 diabetes who initiated GLP-1RA therapy. Baseline HbA1c was measured within 3 months before medication initiation, and follow-up HbA1c was measured after 3 months. The patients with type 2 diabetes were classified as good responders (HbA1c reduction ≥ 2.5 percentage point) or poor responders (HbA1c reduction <0.5 percentage point). Models adjusted for demographic characteristics, anthropometric and metabolic measures, blood pressure, body mass index (BMI), lipid profile, liver function tests, polygenic risk score, and GLP1R variant carrier status were compared between the two groups. Common GLP1R variations were further investigated for carrier frequency and associated HbA1c levels before and after medication use. Results: The cohort included 3194 good responders and 2590 poor responders. Good responders were younger than poor responders (55.2 vs. 58.6 years) and had significantly higher glycemic improvement. HbA1c levels fell from 9.2% to 6.3% in good responders and 8.4% to 8.1% in poor responders, resulting in an absolute HbA1c reduction of 2.9% and 0.3%, respectively. Good responders also showed larger decreases in fasting glucose, BMI, systolic and diastolic blood pressure, triglycerides, total cholesterol, LDL cholesterol, and liver enzymes, as well as minor improvements in HDL-C. After multivariable adjustment, Poor responders had a greater T2D polygenic risk score (0.38 vs. 0.21), more GLP1R coding variant carrier status (10.1% vs. 8.0%), and a higher overall GLP1R variant burden (22.8% vs. 19.2%). Variant-level studies revealed rs2268650 and rs2003132 enrichment among poor responders, with negative post-treatment HbA1c patterns in carriers, whereas good-response carriers showed significant HbA1c improvement. Conclusions: Response to GLP-1RA in T2D is associated with baseline clinical and metabolic status, as well as inherited genetic susceptibility, which includes common GLP1R variation and a larger polygenic risk burden. Integrating clinical and pharmacogenomic profiling may improve patient classification and provide insight into treatment failure in poor responders.

Long-chain fatty acids in the blood are prevented from unfettered movement into nonfenestrated tissues or the arterial wall. During fasting, nonesterified FAs are released from adipose tissue into the circulation and bind to albumin, forming a complex >65 kDa, with limited ability to efficiently cross endothelial cell (EC) barriers without a specific receptor. For this reason, nonhepatic tissue distribution of circulating FA parallels EC expression of the FA-binding protein CD36 (cluster of differentiation 36). The deletion of CD36 in ECs reduces nonesterified FA uptake by the heart, muscle, and brown adipose tissue. The other major transport system for FAs is via lipoproteins. Circulating FAs are contained within TRLs (triglyceride-rich lipoproteins), chylomicrons during the postprandial period, and VLDL (very low-density lipoprotein) both postprandially and during fasting. LPL (lipoprotein lipase) on capillary ECs releases FAs from TRLs and likely allows their passage into tissues, in part, via a CD36-independent process. ECs can also internalize lipoprotein particles, followed by the transendothelial movement of lipids. In this review, we will discuss the pathways of EC uptake of FAs from circulation, how this process affects both EC and tissue biology, and the importance of these processes for systemic metabolism and vascular health. We will conclude with speculations on methods to modulate EC FA uptake and their implications for human health.

Motivation: Ferroptosis is an iron-dependent regulated cell death process involving lipid peroxidation, redox imbalance, and impaired antioxidant defense. It is increasingly relevant to metabolic liver disease and non-alcoholic steatohepatitis. Existing ferroptosis resources mainly provide gene annotations and disease associations, but they do not offer an integrated workflow for user-uploaded transcriptome data, liver-focused enrichment, dataset-level scoring, and ferroptosis-senescence cross-talk analysis. Results: We developed FerroEnrich, an open-source web platform for analyzing ferroptosis and senescence programs in human and mouse liver transcriptome datasets. FerroEnrich supports count matrix upload, metadata-guided differential expression analysis, identification of ferroptosis-prone and ferroptosis-resistant genes, dataset-level ferroptosis index scoring, sample-level susceptibility estimation, curated liver module enrichment, interaction network visualization, and ferroptosis-senescence cross-talk analysis. Application to human advanced non-alcoholic steatohepatitis and mouse diet-induced liver disease datasets demonstrated cross-species utility and identified conserved remodeling, including reduced ferroptosis-protective signatures and increased senescence- and fibrosis-associated modules. Availability and implementation: FerroEnrich is freely available at https://ferroenrich.shinyapps.io/ferroenrich/. Source code, documentation, and demo datasets are available at the FerroEnrich GitHub repository.

Background/Objectives: Roux-en-Y gastric bypass (RYGB) improves obesity-related metabolic disorders, yet post-operative dietary composition critically shapes outcomes. This study explored how RYGB and high-fat diet (HFD) differentially regulate hepatic transcriptional programs. Methods: We performed RNA-seq on liver tissues from diet-induced obese C57BL/6 male mice 8 weeks post-RYGB or sham surgery, maintained on chow or HFD. Differentially expressed genes (DEGs) were identified using DESeq2. Gene sets were categorized as RYGB-induced (commonly regulated by surgery across diets), Reversal (RYGB-driven counter-regulation of obesity-induced changes), and HFD-induced (commonly regulated by diet). A subset of RYGB-specific HFD-induced genes was derived by excluding HFD-induced genes from the RYGB Chow vs. RYGB HFD contrast. Pathway enrichment was conducted using STRING. Results: RYGB induced 365 DEGs, including pathways related to extracellular remodeling and reduced mitochondrial/antioxidant activity. Among these, 119 Reversal genes countered obesity-associated transcriptional patterns and accounted for ~27% of the RYGB-induced enrichment results. HFD regulated 860 DEGs, highlighting stress responses and translational repression. Lastly, a set of 426 RYGB-specific HFD-induced genes revealed persistent hepatic inflammation, coagulation, and iron dysregulation under HFD despite surgery. Conclusions: RYGB induces robust hepatic transcriptomic changes that attenuate obesity-driven dysregulation, including a coordinated reprogramming of iron-handling pathways. However, high dietary fat partially overrides these benefits, promoting inflammatory, metabolic stress, and iron-related stress. Optimizing post-operative diets and carefully managing micronutrient intake, especially iron, may enhance RYGB’s metabolic efficacy and long-term liver health.

Increased fasting and postprandial triglyceride levels are risk factors for cardiovascular disease (CVD). Partially metabolized triglyceride-rich lipoproteins (TRLs) termed remnants are created when intestinally-derived chylomicrons and liver secreted very low density lipoproteins (VLDLs) interact with lipoprotein lipase (LpL) situated on the luminal surface of capillary endothelial cells. Higher circulating remnant levels have been implicated as the reason for the relationship between TRL levels and CVD. We hypothesized that nascent lipoproteins not only remnants are atherogenic. To test this, we created mice with induced whole-body lipoprotein lipase (LpL) deficiency combined with LDL receptor (LDLR) deficiency. On an atherogenic Western-type diet (WD), male and female mice with induced global LpL deficiency (iLpl^-/-) and LDLR knockdown (Ldlr^kd) developed hypertriglyceridemia and elevated cholesterol levels; all the increased cholesterol was in chylomicrons or large VLDL. After 12 weeks on a WD, atherosclerotic lesions both in the brachiocephalic artery and the aortic root were more severe in iLpl^-/-/Ldlr^kd mice than control Ldlrkd mice. Aorta from hypertriglyceridemic mice had changes in the transcriptomes of endothelial cells, macrophages, and smooth muscle cells indicating vascular inflammation. Our data show that intact TRLs contribute to atherosclerosis, explain the association of postprandial lipemia and vascular disease and prove that non-remnant TRLs are not benign.

BACKGROUND: Movement of circulating lipids into tissues and arteries requires transfer across the endothelial cell (EC) barrier. This process allows the heart to obtain fatty acids, its chief source of energy, and apoB-containing lipoproteins to cross the arterial endothelial barrier, leading to cholesterol accumulation in the subendothelial space. Multiple studies have established elevated postprandial TRLs (triglyceride-rich lipoproteins) as an independent risk factor for cardiovascular disease. We explored how chylomicrons affect ECs and transfer their fatty acids across the EC barrier. METHODS: We had reported that media from chylomicron-treated ECs lead to lipid droplet formation in macrophages. To determine the responsible component of this media, we assessed whether removing the extracellular vesicles (EVs) would obviate this effect. EVs from control and treated cells were then characterized by protein, lipid, and microRNA content. We also studied the EV-induced transcription changes in macrophages and ECs and whether knockdown of SR-BI (scavenger receptor-BI) altered these responses. In addition, using chylomicrons labeled with [ ¹³ C]oleate, we studied the uptake and release of this labeled by ECs. RESULTS: Chylomicron treatment of ECs led to an inflammatory response that included production of EVs that drove macrophage lipid droplet accumulation. The EVs contained little free fatty acids and triglycerides, but abundant phospholipids and diacylglycerols. In concert with this, [ ¹³ ]C labeled chylomicron triglycerides exited ECs primarily in phospholipids. EVs from chylomicron-treated versus untreated ECs were larger, more abundant, and contained specific microRNAs. Treatment of macrophages and naive ECs with media from chylomicron-treated ECs increased expression of inflammatory genes. CONCLUSIONS: EC chylomicron metabolism produces EVs that increase macrophage inflammation and create LDs. Media containing these EVs also increases EC inflammation, illustrating an autocrine inflammatory process. Fatty acids within chylomicron triglycerides are converted to phospholipids within EVs. Thus, EC uptake of chylomicrons constitutes an important pathway for vascular inflammation and tissue lipid acquisition.

Background: Schizophrenia is a complex neuropsychiatric disorder whose pathophysiology may involve oxidative stress-induced neuronal damage and inflammation. We conducted a cross-species study to elucidate oxidative stress dysregulation in schizophrenia. Methods: We measured peripheral oxidative stress biomarkers (malondialdehyde [MDA], nitric oxide [NO], reduced glutathione [GSH], superoxide dismutase [SOD], catalase [CAT], advanced protein oxidation products [APOP]), and C-reactive protein (CRP) in antipsychotic-naïve schizophrenia patients and matched controls. We also assayed liver enzymes (ALP, ALT, AST) as indicators of systemic metabolic stress. In parallel, we re-analyzed published single-cell RNA-sequencing data from a Setd1a^+/–^ mouse model of schizophrenia, focusing on prefrontal cortex (PFC) cell types and oxidative stress-related gene expression. Results: Patients with schizophrenia showed markedly elevated MDA and NO (indicators of lipid and nitrosative stress) and significantly reduced antioxidant defenses (GSH, SOD, CAT) versus controls (p < 0.01 for all comparisons). Notably, urban patients exhibited higher oxidative stress biomarker levels than rural patients, implicating environmental contributions. Liver function tests revealed increased ALT, AST, and ALP in schizophrenia, suggesting hepatic/metabolic dysregulation. Single-cell analysis confirmed dysregulated redox pathways in the schizophrenia model; PFC neurons from Setd1a^+/–^ mice displayed significantly lower expression of key antioxidant genes (e.g., Gpx4, Nfe2l2) compared to wild-type, indicating impaired glutathione metabolism. Conclusions: Our integrative data identify convergent oxidative stress imbalances in schizophrenia across species. These findings advance a mechanistic understanding of schizophrenia as a disorder of redox dysregulation and inflammation. They also have translational implications as augmenting antioxidant defenses (for example, with N-acetylcysteine or vitamins C/E) could mitigate oxidative injury and neuroinflammation in schizophrenia, representing a promising adjunct to antipsychotic therapy.

Background: Schizophrenia is a complex neuropsychiatric disorder whose pathophysiology may involve oxidative stress–induced neuronal damage and inflammation. We conducted a cross-species study to elucidate oxidative stress dysregulation in schizophrenia. Methods: We measured peripheral oxidative markers (malondialdehyde [MDA], nitric oxide [NO], reduced glutathione [GSH], superoxide dismutase [SOD], catalase [CAT], advanced protein oxidation products [APOP]) and C-reactive protein (CRP) in antipsychotic-naïve schizophrenia patients and matched controls. We also assayed liver enzymes (ALP, ALT, AST) as indicators of systemic metabolic stress. In parallel, we re-analyzed published single-cell RNA-sequencing data from a Setd1a^+/–^ mouse model of schizophrenia [1] }, focusing on prefrontal cortex (PFC) cell types and oxidative stress–related gene expression. Results: Patients with schizophrenia showed markedly elevated MDA and NO (indicators of lipid and nitrosative stress) and significantly reduced antioxidant defenses (GSH, SOD, CAT) versus controls (p<0.01 for all comparisons). Notably, urban patients exhibited higher oxidative marker levels than rural patients, implicating environmental contributions. Liver function tests revealed increased ALT, AST, and ALP in schizophrenia, suggesting hepatic/ metabolic dysregulation. Single-cell analysis confirmed dysregulated redox pathways in the schizophrenia model: PFC neurons from Setd1a^+/–^ mice displayed significantly lower expression of key antioxidant genes (e.g. Gpx4, Nfe2l2) compared to wild-type, indicating impaired glutathione metabolism. Conclusions: Our integrative data identify convergent oxidative stress imbalances in schizophrenia across species. The findings advance mechanistic understanding of schizophrenia as a disorder of redox dysregulation and inflammation. They also have translational implications: augmenting antioxidant defenses (for example, with Nacetylcysteine or vitamins C/E) could mitigate oxidative injury and neuroinflammation in schizophrenia, representing a promising adjunct to antipsychotic therapy.

Glucose transporter-1 is known for regulating glucose uptake in brain endothelial cells. This study used global transcriptome analysis and diabetic mouse models to reveal the novel role of glucose transporter 1 in regulating brain endothelial cell homeostasis by reducing the inflammation response and increasing the protection mechanism. Importantly, the glucose transporter 1-dependent protection mechanism is compromised in diabetic conditions, which explains why patients with diabetes have a high risk of cerebrovascular diseases.