👤 Balu Chakravarthy

Biased agonism of the glucagon-like peptide-1/glucose-dependent insulinotropic polypeptide receptors (GLP-1R/GIPR) yields greater weight loss and better glycemic control than unbiased agonism in preclinical models. To evaluate whether biased agonism translates into improved efficacy for weight loss and glycemic control in clinical settings, we developed and characterized CT-388, a unimolecular peptide-based dual GLP-1R/GIPR agonist that is cAMP signal-biased at both receptors. In cell-based assays, CT-388 activated GLP-1R and GIPR with both having minimal receptor internalization vs their native ligands. CT-388 improved glycemic control in mice and monkeys, and reduced bodyweight, suppressed appetite, and improved metabolic dysfunction-associated steatohepatitis pathology in mice. In a phase 1, double-blind, randomized, placebo-controlled clinical study (NCT04838405) of CT-388 (subcutaneously administered single doses [0.5-7.5 mg] or 4 once-weekly doses [5-12 mg]) in otherwise healthy participants with overweight or obesity, CT-388 was generally well tolerated with a safety profile consistent with other incretin-based therapies; most treatment-emergent adverse events were mild or moderate. Glycemic parameters were improved during fasting conditions and an oral glucose tolerance test. The mean percent change in bodyweight from baseline to day 29 was -4.7% to -8.0% across CT-388 doses vs -0.5% with placebo. CT-388 pharmacokinetics supported once-weekly dosing. In conclusion, CT-388 demonstrated strong translatability from preclinical to clinical studies with consistent pharmacokinetics and pharmacodynamics across multiple species. In clinical settings, 4 weeks of CT-388 treatment produced clinically meaningful weight loss and improved glycemic control with favorable tolerability. These findings warrant further clinical evaluation of CT-388 for treating obesity and type 2 diabetes. Show less

Glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists have recently been shown to play a significant role in the treatment of diabetes and obesity. Better understanding of their signaling and mechanism of action could further improve their therapeutic effects. In the current study, we investigate the impact of biased cyclic AMP (cAMP) signaling of GLP-1R and GIPR, individually, as well as the combined effects of a unimolecular dually biased GLP-1R/GIPR agonist, CT-859, on glucose, food consumption, and body weight regulation. Our data demonstrate that biased agonism of either GLP-1R or GIPR leads to better glycemic regulation, greater food intake suppression, and weight loss. In addition, concerted biased activation of both GLP-1R and GIPR results in substantially higher efficacy. Activation of GLP-1R and GIPR with a combination of individually biased agonists or via a dually biased unimolecular approach with CT-859 may provide significant therapeutic advantages for the treatment of diabetes and obesity. Show less

We have designed the first antigen-less pro-vaccine, named 8206, for treating autoimmune diseases. Composed of dexamethasone, rapamycin, and R848 at a mass ratio of 8:20:6, 8206 is a complete tolerogenic adjuvant that acts systemically to form an active vaccine in situ with endogenous pathogenic autoantigens. This active vaccine suppresses autoimmunity by expanding antigen-specific Treg cells in affected tissues. In a mouse model of atherosclerosis, 8206 successfully targeted all three analyzed pathogenic autoantigens (ApoB, HSP60, and HMGB1) and inhibited disease progression. These findings suggest that 8206 can potentially serve as a universal treatment vaccine for autoimmune diseases by eliminating the need for exogenous immunogens, with implications for broad applications in immunotherapy. Show less

Fatty acid metabolism is perturbed in atherosclerotic lesions, but whether it affects lesion formation is unknown. To determine whether fatty acid synthesis affects atherosclerosis, we inactivated fatty-acid synthase (FAS) in macrophages of apoE-deficient mice. Serum lipids, body weight, and glucose metabolism were the same in FAS knock-out in macrophages (FASKOM) and control mice, but blood pressure was lower in FASKOM animals. Atherosclerotic extent was decreased 20-40% in different aortic regions of FASKOM as compared with control mice on Western diets. Foam cell formation was diminished in FASKOM as compared with wild type macrophages due to increased apoAI-specific cholesterol efflux and decreased uptake of oxidized low density lipoprotein. Expression of the anti-atherogenic nuclear receptor liver X receptor alpha (LXRalpha; Nr1h3) and its downstream targets, including Abca1, were increased in FASKOM macrophages, whereas expression of the potentially pro-atherogenic type B scavenger receptor CD36 was decreased. Peroxisome proliferator-activated receptor alpha (PPARalpha) target gene expression was decreased in FASKOM macrophages. PPARalpha agonist treatment of FASKOM and wild type macrophages normalized PPARalpha target gene expression as well as Nr1h3 (LXRalpha). Atherosclerotic lesions were more extensive when apoE null mice were transplanted with LXRalpha-deficient/FAS-deficient bone marrow as compared with LXRalpha-replete/FAS-deficient marrow, consistent with anti-atherogenic effects of LXRalpha in the context of FAS deficiency. These results show that macrophage FAS deficiency decreases atherosclerosis through induction of LXRalpha and suggest that FAS, which is induced by LXRalpha, may generate regulatory lipids that cause feedback inhibition of LXRalpha in macrophages. Show less

The mechanisms underlying growth factor preconditioning of neurons are only partially elucidated, and no studies have been conducted in this area using a gene profiling approach. We used cDNA microarrays to compare the transcriptional profiles of cells preconditioned either with insulin-like growth factor I (IGF-1) or basic fibroblast growth factor (bFGF), to identify differentially regulated genes that may function in growth factor signaling, response to oxygen-glucose deprivation (OGD), and most importantly, cell survival. Primary rat cortical cultures were treated with bFGF or IGF-1 for 2, 24, or 24 h followed by OGD for 90 min, and compared with cells that were subject to OGD without growth factor pretreatment. Although the majority of surveyed genes were unchanged in all experimental treatments, 175 genes (10% of the cDNAs on the chip) were found to be differentially regulated in at least one of the treatment conditions. Hierarchical clustering of these 175 genes was used to identify four expression clusters: IGF-1 regulated, bFGF regulated, OGD regulated, and putative neuroprotective genes. Further analysis using realtime RT-PCR confirmed that we had identified genes that are regulated by single growth factors, as well as several more that are co-regulated by both IGF-1 and bFGF. These genes can influence neuronal survival by affecting diverse pathways such as growth factor signal transduction (CD44, DTR, DUSP6, EPS8, IGFBP3), DNA repair and transcription (FOXJ1), metabolic homeostasis (RASA1, SHMT2), cytoskeletal stability (MSN, MAPT) and cholesterol biosynthesis (FDFT1, FDPS). Show less