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Lipid metabolism is closely related to the improvement of vascular calcification (VC) in chronic kidney disease (CKD). Globular adiponectin (gAd) has been reported to be involved in the development of VC in CKD, but the detailed regulatory role remains unclear. The present study is aimed to investigate the biological function and the underlying regulation mechanism of gAd in the process of VC during CKD. Vascular smooth muscle cells (VSMCs) calcification was determined by Alizarin Red S staining. Protein signaling related with VC was tested by western blotting. The expression and intracellular localization of runt-related transcription factor 2 (Runx2) was detected by immunofluorescence and uraemic rat with VC was established by a two-step nephrectomy. Combined with the results of Alizarin Red S staining, we discovered that β-glycerophosphate (β-Gp)-induced the osteoblastic differentiation of VSMCs was significantly reversed by gAd treatment. Along with the VSMCs calcification and the increase of Runx2 in β-Gp-exposed VSMCs, the activities of protein kinase B (AKT) and Wnt/β-catenin pathway were enhanced, but that were counteracted by the exposure of gAd in rat and human VSMCs. After administration with agonists of the Wnt (SKL2001) and AKT (SC79), there appeared more osteoblastic differentiation and higher expression of Runx2 in gAd-treated VSMCs, but showing lower impact in the presence of SC79 than that in the presence of SKL2001. In the in vivo experiments, intravenous injection of gAd also significantly inhibited VC and Runx2 level in uraemic rat in a dose-dependent manner, possibly through regulating Wnt/β-catenin pathway. This study demonstrates that gAd ameliorates osteoblastic differentiation of VSMCs possibly by blocking PI3K/AKT and Wnt/β-catenin signaling transduction. The findings provide an important foundation for gAd in treating VC in kidney diseases. Supplementary Information The online version contains supplementary material available at 10.1007/s10735-021-10012-2.

Purpose: To evaluate the efficacy of adiponectin (APN)-derived short peptides (ADPs) 355 compared with globular APN in a mouse model of experimental dry eye (EDE) and corneal alkali burn. Methods: ...

Purpose: Adiponectin has been shown to exert potent anti-inflammatory activities in a range of systemic inflammatory diseases. This study aimed to investigate the potential therapeutic effects of KS23, a globular adiponectin-derived peptide, on endotoxin-induced uveitis (EIU) in rats and lipopolysaccharide (LPS)-stimulated mouse macrophage-like RAW 264.7 cells.Methods: EIU was induced in Lewis rats by subcutaneous injection of LPS into a single footpad. KS23 or phosphate-buffered saline (PBS) was administered immediately after LPS induction via intravitreal injection. Twenty-four hours later, clinical and histopathological scores were evaluated, and the aqueous humor (AqH) was collected to determine the infiltrating cells, protein concentration, and levels of inflammatory cytokines. In vitro, cultured RAW 264.7 cells were stimulated with LPS in the presence or absence of KS23, inflammatory cytokine levels in the supernatant, nuclear translocation of nuclear factor kappa B (NF-κB) subunit p65, and the expression of NF-kB signaling pathway components were analyzed.Results: KS23 treatment significantly ameliorated the clinical and histopathological scores of EIU rats and reduced the levels of infiltration cells, protein, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the aqueous humor. Consistently, KS23 decreased the expression of TNF-α and IL-6 in the supernatant of LPS-stimulated RAW 264.7 cells and inhibited the LPS-induced nuclear translocation of NF-κB p65 and the phosphorylation of IKKα/β/IκBα/NF-κB.Conclusion: The in vivo and in vitro results demonstrated the anti-inflammatory effects of the peptide KS23 and suggested that KS23 is a compelling, novel therapeutic candidate for the treatment of ocular inflammation.

Objectives: Adiponectin, a multifunction adipokine with established cardioprotective effect, presents in high molecular weight (HMW) and globular isotype (gAPN). Recent study demonstrated that HMW cardioprotection depends on T-Cadherin (TCad). However, whether TCad also mediates the cardioprotective effects of gAPN, an isotype with much greater biological activity and wildly utilized in metabolic/cardiovascular investigations, remains unclear. Methods and results: Adult male WT, AdipoR1KO and TCadKO mice were subjected to MI, treated with vehicle or gAPN, and followed for 4 weeks. Knockout of AdipoR1, but not Tcad, abolished the cardioprotective effects of gAPN observed in WT mice, indicating that AdipoR1 but not Tcad mediates gAPN cardioprotection. Unexpectedly, we observed that gAPN cardioprotection was significantly attenuated when animals were pre-treated with GW4869, suggesting exosome involvement. To further delineate whether gAPN regulates exosome biogenesis and/or uptake and which stage is mediated by AdipoR1, cardiomyocytes were isolated from adult AdipoR1KO and TCadKO mice. Effects of gAPN and HMW upon exosome generation and uptake were evaluated. Surprisingly, cardiomyocyte exosome production was dramatically increased (8-fold) when cells were treated with gAPN but not with HMW (at 5-fold concentration of gAPN). Moreover, gAPN increases cardiomyocyte exosome production in a receptor-independent fashion and is achieved by regulating ESCRT-multivesicular body (MVB) pathway. However, gAPN stimulated exosome uptake and cellular protection observed in WT cardiomyocytes was abolished in AdipoR1KO-derived but no TCadKO-derived cardiomyocytes. Conclusions: These data demonstrated that gAPN and HMW cardioprotection exhibits different receptor dependence and is mediated by distinct mechanisms. HMW protects heart via binding with TCad. However, gAPN has a unique ability, promoting exosome biogenesis in a receptor-independent fashion and stimulating exosome uptake and cardioprotection in an AdipoR1-dependent manner. These results indicate that gAPN is superior to HMW in concerning cardioprotection against ischemia heart injury, and is a promising therapeutic strategy in patients with coronary artery disease.

In this study, human globular adiponectin-glucagon-like peptide-1 analog (gAd-GLP-1-A) fu- sion protein was expressed and its glucose-lowering effect was measured in vivo. We con- structed a prokaryotic expression vector PET28a-gAd-GLP-1-A and transformed the vector into Escherichia coli BL21 (DE3). A recombinant fusion protein of about 25KD was expressed from BL21 (DE3) cells after isopropylthio--D-galactoside induction. This protein was N-terminal His-tagged gAd-GLP-1-A fusion protein. Most of the protein was expressed in inclusion body. The fusion protein in inclusion body was purified by using High-Affinity Nickel Iminodiacetic Acid Resin and refolded in urea gradient refolding buffer. The refolded protein was incubated with enterokinase to remove the N-terminal His-tag. The fusion protein without His-tag is gAd-GLP-1-A fusion protein, which exhibited significant glu- cose-lowering effect in diabetic mice.

Adiponectin administration to obese or type 2 diabetic patients is still far off, due to its expensive costs and absence of studies demonstrating the effectiveness of its chronic administration. We performed long-term globular adiponectin administration, testing its usefulness in improving adipose tissue metabolism. Adiponectin (98 υg/day) was administered through a subcutaneous minipump with continued release (28 days) to Wistar rats fed a high-fat diet. Adiponectin decreased body weight and adipocyte size, while decreasing circulating leptin levels. More, adiponectin was able to increase IkappaBalpha and PPARgamma levels and to prevent high-fat diet-induced impairment of insulin signalling, especially in epididymal adipose tissue. This resulted in improved glucose profile. High-fat diet caused an impairment of lipolysis in epididymal adipose tissue, which was partially restored by adiponectin treatment. Long-term globular adiponectin administration was able to improve pathways of insulin signalling and lipid storage in adipose tissue of high-fat diet-fed rats, contributing to a better metabolic profile.

We read with interest the recent articles by Hattori et al. (1,2), which report activation of nuclear factor-κB (NF-κB) transcription by the recombinant globular domain of adiponectin. However, these findings contrast directly with a substantial body of published and ongoing work. As initially reported by Ouchi et al. and confirmed by other groups (3,4), a major effect of adiponectin is the suppression of proinflammatory endothelial responses, which include reversing the activation of NF-κB, reducing adhesion molecule expression, and enhancing nitric oxide bioavailability. We have shown that the globular domain of adiponectin also suppresses endothelial reactive oxygen species generation in response to various agonists, including oxidized LDL and high glucose (5,6). At the American Diabetes Association 66th …

Goldstein et al. (1) expressed concern that our findings of nuclear factor-κB (NF-κB) activation by the globular domain adiponectin appear to contradict a substantial body of published and ongoing work. We showed that globular adiponectin activates redox-sensitive transcription factors in two different cell types: vascular endothelial cells and cardiac fibroblasts (2,3). These findings do not always contrast with a substantial body of published work. Indeed, a very recent report suggests that adiponectin exerts proinflammatory activities in colon by inducing production of proinflammatory cytokines and inhibiting bioactivity of protective growth factors (4). As initially reported by Ouchi et al. (5), adiponectin suppresses …