Direct CCL4 Inhibition Modulates Gut Microbiota, Reduces Circulating Trimethylamine N-Oxide, and Improves Glucose and Lipid Metabolism in High-Fat-Diet-Induced Diabetes Mellitus

Abstract

Purpose: Modulation of the gut microbiota may lead to changes in pathological conditions. C-C chemokine motif ligand (CCL) 4 was upregulated in diabetes mellitus (DM) and was shown to play a significant role in pancreatic inflammation and glucose metabolism. The detailed in vivo mechanisms have not been well explored. This study aimed to investigate the hypothesis that direct CCL4 inhibition could modify gut microbiota and systemic metabolism in diet-induced DM mice. Methods: C57BL/6 mice fed a high-fat diet (HFD) were used as a diet-induced DM model. CCL4 inhibition was conducted by anti-CCL4 neutralizing monoclonal antibodies. The gut microbiota was analyzed by high-throughput sequencing of the 16S rRNA. Fecal microbiota transplantation (FMT) was used to verify the effect of CCL4 deficiency on gut microbiota and the linkage between CCL4-modulated gut microbiota and HFD-induced DM. Results: CCL4 inhibition stabilized glucose homeostasis, modulated lipid parameter, and decreased inflammatory markers in HFD-induced DM mice. Moreover, CCL4 inhibition reversed HFD-induced gut dysbiosis, evidenced by the decreased abundance of family Muribaculaceae and increased abundance of family Atopobiaceae when CCL4 antibodies were administrated. CCL4 inhibition led to a decrease in circulating trimethylamine N-oxide levels, a proinflammatory metabolite from gut microbiota. Taken together, CCL4 inhibition could modify gut microbiota profiles, suppress proinflammatory metabolites, reduce systemic inflammation, improve insulin resistance, and retard the progression of hyperglycemia in HFD-induced DM. Furthermore, FMT from CCL4 knockout mice rescued the glucose homeostasis in HFD-induced DM mice. Conclusion: Our findings may not only provide a novel rationale to in vivo CCL4-based therapeutic approach in diet-induced DM but also indicate the significance of gut microbiota profile including the family Muribaculaceae and the family Atopobiaceae as a potential modifiable target for systemic metabolism.

Dose-Response Associations of Metabolic Score for Insulin Resistance Index with Nonalcoholic Fatty Liver Disease among a Nonobese Chinese Population: Retrospective Evidence from a Population-Based Cohort Study

“…It is well known that insulin resistance (IR) is implicated in critical aspects of the pathogenesis of NAFLD [ 18 – 20 ]. The homeostasis model assessment for insulin resistance (HOMA-IR) index is the method that is most commonly employed to assess the degree of IR [ 21 , 22 ].…”

Alterations in mouse visceral adipose tissue mRNA expression of islet G‐protein‐coupled receptor ligands in obesity

“…These beneficial effects of Ccl4 blockade may be linked to reduction in Ccl4‐induced β‐cell inflammation as expression of the inflammatory cytokines, IL‐6 and TNF‐α, was reduced in the NIT‐1 β‐cell line by siRNA‐mediated knockdown of Ccr2 and Ccr5, GPCRs for which Ccl4 is a ligand 32 . In support of these observations, another study which also utilised anti‐Ccl4 antibodies reported that Ccl4 inhibition improved insulin sensitivity and lipid profiles, delayed the progression of hyperglycaemia and reduced systemic inflammation in high‐fat diet‐fed mice 33 . Ccl4 acts as a ligand for Ccr1, Ccr2, Ccr5 and Ccr9, and we have identified that mRNAs encoding CCR1 and CCR9 are significantly up‐regulated in human islets from obese subjects 34 .…”

“… 32 In support of these observations, another study which also utilised anti‐Ccl4 antibodies reported that Ccl4 inhibition improved insulin sensitivity and lipid profiles, delayed the progression of hyperglycaemia and reduced systemic inflammation in high‐fat diet‐fed mice. 33 Ccl4 acts as a ligand for Ccr1, Ccr2, Ccr5 and Ccr9, and we have identified that mRNAs encoding CCR1 and CCR9 are significantly up‐regulated in human islets from obese subjects. 34 There are no current reports on the role of Ccl4 on islet function, but the upregulation of mRNAs encoding adipose tissue Ccl4 and islet CCR1 and CCR9 in obesity suggests that increased release of Ccl4 from adipocytes in obesity could reduce insulin secretion via activation of one, or both, of these Gαi‐coupled islet receptors, exacerbating its effects to induce inflammation and insulin resistance.…”

CCL4 participates in the reprogramming of glucose metabolism induced by ALV-J infection in chicken macrophages

“…Importantly, CCL4 inhibits ALV-J-mediated reprogramming of glucose metabolism in chicken macrophages. One recent study also showed that CCL4 plays a signi cant role in glucose metabolism and upregulated in diabetes mellitus (Chang et al 2021). CCL4 may be involved in glucose metabolism through its receptor C-C chemokine receptor 5 (CCR5).…”