Cover Story Current Issue

Maternal nutrition exerts profound and lasting effects on infant development, with implications extending beyond somatic growth to long-term brain function and metabolic health. For example, newborns from mothers with obesity or diabetes exhibit increased susceptibility to metabolic disorders, including insulin resistance (IR) and type 2 diabetes (T2D), often emerging in childhood or adolescence. While genetic inheritance contributes to this intergenerational risk, early-life nutritional exposures are increasingly recognized as primary drivers of persistent metabolic programming. Among key classes of nutrients, branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—have emerged as potent modulators of metabolic health in human adults. Elevated circulating BCAAs are among the most accurate predictors of future insulin resistance (IR) and T2D, with a two-fold increase in serum levels conferring a 2.5-fold risk of diabetes onset within 6–10 years. This elevation can directly cause organ toxicity, exacerbating metabolic deficits in a feed-forward loop. However, the extent to which maternal BCAA overnutrition during gestation and lactation impacts offspring metabolic programming and predisposes to dysfunction remains unclear.

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Current Issue

Whole body and hematopoietic cell-specific deletion of G-protein coupled receptor 65 (GPR65) improves insulin sensitivity in diet-induced obese mice

Yingjiang Zhou, EunJu Bae, Simon S. Hoffman, Da Young Oh, ... Saswata Talukdar

Whole body and hematopoietic cell-specific deletion of G-protein coupled receptor 65 (GPR65) improves insulin sensitivity in diet-induced obese mice

 

Objective

Acidic extracellular microenvironments, resulting from enhanced glycolysis and lactic acid secretion by immune cells, along with metabolic acidosis may interfere with the insulin signaling pathway and contribute to the development of insulin resistance. In the present study, we investigated the role of G protein-coupled receptor GPR65, an extracellular pH sensing protein, in modulating insulin resistance.

Methods

We measured GPR65 expression in the adipose tissue (AT) of subjects with varying metabolic health states. We utilized whole-body and hematopoietic cell-specific GPR65 knockout (KO) mice to investigate the mechanism underlying the associations between GPR65, inflammatory response, and insulin resistance.

Results

Elevated GPR65 expression was observed in the AT of subjects with obesity, compared to their lean counterparts, and was inversely correlated with insulin resistance. In GPR65 KO mice, improved insulin sensitivity and decreased hepatic lipid content were observed, attributed to concomitant increases in mitochondrial activity and fatty acid β-oxidation in liver. GPR65 KO mice also exhibited increased Akt phosphorylation in skeletal muscle, suppressed proinflammatory gene expression in AT, and decreased serum cytokine levels, collectively suggesting the anti-inflammatory effects of GPR65 depletion. This was further confirmed by observations of decreased macrophage chemotaxis towards AT in vitro, and depressed inflammatory signaling pathway activation in bone marrow-derived dendritic cells from GPR65 KO mice. Additionally, hematopoietic lineage-specific GPR65 KO mice exhibited improved whole body insulin sensitivity in clamp studies, demonstrating GPR65 signaling in immune cells mediates this effect.

Conclusions

Our data suggests that macrophage-specific GPR65 signaling contributes to inflammation and the development of insulin resistance.

 

Articles in Press

Whole body and hematopoietic cell-specific deletion of G-protein coupled receptor 65 (GPR65) improves insulin sensitivity in diet-induced obese mice

Yingjiang Zhou, EunJu Bae, Simon S. Hoffman, Da Young Oh, ... Saswata Talukdar

Whole body and hematopoietic cell-specific deletion of G-protein coupled receptor 65 (GPR65) improves insulin sensitivity in diet-induced obese mice

 

Objective

Acidic extracellular microenvironments, resulting from enhanced glycolysis and lactic acid secretion by immune cells, along with metabolic acidosis may interfere with the insulin signaling pathway and contribute to the development of insulin resistance. In the present study, we investigated the role of G protein-coupled receptor GPR65, an extracellular pH sensing protein, in modulating insulin resistance.

Methods

We measured GPR65 expression in the adipose tissue (AT) of subjects with varying metabolic health states. We utilized whole-body and hematopoietic cell-specific GPR65 knockout (KO) mice to investigate the mechanism underlying the associations between GPR65, inflammatory response, and insulin resistance.

Results

Elevated GPR65 expression was observed in the AT of subjects with obesity, compared to their lean counterparts, and was inversely correlated with insulin resistance. In GPR65 KO mice, improved insulin sensitivity and decreased hepatic lipid content were observed, attributed to concomitant increases in mitochondrial activity and fatty acid β-oxidation in liver. GPR65 KO mice also exhibited increased Akt phosphorylation in skeletal muscle, suppressed proinflammatory gene expression in AT, and decreased serum cytokine levels, collectively suggesting the anti-inflammatory effects of GPR65 depletion. This was further confirmed by observations of decreased macrophage chemotaxis towards AT in vitro, and depressed inflammatory signaling pathway activation in bone marrow-derived dendritic cells from GPR65 KO mice. Additionally, hematopoietic lineage-specific GPR65 KO mice exhibited improved whole body insulin sensitivity in clamp studies, demonstrating GPR65 signaling in immune cells mediates this effect.

Conclusions

Our data suggests that macrophage-specific GPR65 signaling contributes to inflammation and the development of insulin resistance.

 

SAVE THE DATE!

13th
Helmholtz Diabetes Conference 
Munich, 21-23. Sep 2026                                                                                                                             

2024 impact factor: 6.6

You are what you eat

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