Klotho suppresses the inflammatory responses and ameliorates cardiac dysfunction in aging endotoxemic mice

Review and meta-analysis of genetic polymorphisms associated with exceptional human longevity

BACKGROUND

Many factors contribute to exceptional longevity, with genetics playing a significant role. However, to date, genetic studies examining exceptional longevity have been inconclusive. This comprehensive review seeks to determine the genetic variants associated with exceptional longevity by undertaking meta-analyses.

METHODS

Meta-analyses of genetic polymorphisms previously associated with exceptional longevity (85+) were undertaken. For each variant, meta-analyses were performed if there were data from at least three independent studies available, including two unpublished additional cohorts.

RESULTS

Five polymorphisms, ACE rs4340, APOE ε2/3/4, FOXO3A rs2802292, KLOTHO KL-VS and IL6 rs1800795 were significantly associated with exceptional longevity, with the pooled effect sizes (odds ratios) ranging from 0.42 (APOE ε4) to 1.45 (FOXO3A males).

CONCLUSION

In general, the observed modest effect sizes of the significant variants suggest many genes of small influence play a role in exceptional longevity, which is consistent with results for other polygenic traits. Our results also suggest that genes related to cardiovascular health may be implicated in exceptional longevity. Future studies should examine the roles of gender and ethnicity and carefully consider study design, including the selection of appropriate controls.

PTH, vitamin D, and the FGF-23-klotho axis and heart: Going beyond the confines of nephrology

BACKGROUND

Profound disturbances in mineral metabolism are closely linked to the progression of chronic kidney disease. However, increasing clinical and experimental evidence indicates that alterations in phosphate homoeostasis could have an even stronger impact on the heart.

AIM

The aim of this review is to provide the reader with an update of how alterations in mineral metabolism are related to direct and indirect cardiotoxic effects beyond the nephrology setting.

RESULTS

Evidence exists that alterations in mineral metabolism that are related to changes in parathyroid hormone (PTH), vitamin D, and the FGF-23-klotho axis have direct pathological consequences for the heart. Alterations in plasma PTH levels are associated with cardiac dysfunction and detrimental cardiac remodelling. Several clinical studies have associated vitamin D deficiency with the prevalence of cardiovascular disease (CV) and its risk factors. Recent evidences support deleterious direct and nonphosphaturic effects of FGF-23 on the heart as hypertrophy development. In contrast, reduced systemic klotho levels are related to CV damage, at least when advanced age is present. In addition, we discuss how these mineral metabolism molecules can counteract each other in some situations, in the context of failed clinical trials on cardiac protection as is the case of vitamin D supplementation.

CONCLUSIONS

Among all mineral components, an increase in systemic FGF-23 levels is considered to have the greatest CV impact and risk. However, it is quite possible that many intracellular mechanisms mediated by FGF-23, especially those related to cardiomyocyte function, remain to be discovered.

A novel electrochemical immunosensor based on PG for early screening of depression markers-heat shock protein 70

In this study, a novel electrochemical immunosensor for early screening of depression markers-heat shock protein 70 (HSP70) was successfully developed based on the porous graphene (PG) with huge specific surface area and excellent structure. Benefiting from the strong adsorption and good bioactivity of PG which was initially prepared via a simple pyrolysis process, a variety of heat shock protein70 (HSP70) can be firmly loaded on the PG to construct the basic electrode (HSP70/PG/GCE)，which was characterized by the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. Due to the HSP70 fixed on the surface of basic electrode and the HSP70 in the samples can competitively combine with the horseradish peroxidase labeled human HSP 70 antibody (HRP-Strept-Biotin-Ab). As a result, it presented a negative correlation between the concentration of HSP70 in samples and the detection signal of the proposed electrochemical immunosensor (HRP-Strept-Biotin-Ab-HSP70/PG/GCE) in the test liquid. The application of PG with excellent electrical conductivity in construction of immunosensor remarkably improved the sensitivity of the immunosensor for detection of HSP70. The proposed immunosensor demonstrated a wide linear range of 0.0448 ~ 100 ng/mL with a low detection limit of 0.02 ng/mL at 3σ. Moreover, the proposed immunosensor could be applied for the sensitive and efficient detection of HSP70 in real samples with good precision, acceptable stability, reproducibility and satisfactory results. Therefore, the HSP70 immunosensor provides a novel and convenient method for early clinical screening of depression markers-heat shock protein 70.

Macrophages escape Klotho gene silencing in the mdx mouse model of Duchenne muscular dystrophy and promote muscle growth and increase satellite cell numbers through a Klotho-mediated pathway

Duchenne muscular dystrophy (DMD) is a muscle wasting disease in which inflammation influences the severity of pathology. We found that the onset of muscle inflammation in the mdx mouse model of DMD coincides with large increases in expression of pro-inflammatory cytokines [tumor necrosis factor-α (TNFα); interferon gamma (IFNγ)] and dramatic reductions of the pro-myogenic protein Klotho in muscle cells and large increases of Klotho in pro-regenerative, CD206+ macrophages. Furthermore, TNFα and IFNγ treatments reduced Klotho in muscle cells and increased Klotho in macrophages. Because CD206+/Klotho+ macrophages were concentrated at sites of muscle regeneration, we tested whether macrophage-derived Klotho promotes myogenesis. Klotho transgenic macrophages had a pro-proliferative influence on muscle cells that was ablated by neutralizing antibodies to Klotho and conditioned media from Klotho mutant macrophages did not increase muscle cell proliferation in vitro. In addition, transplantation of bone marrow cells from Klotho transgenic mice into mdx recipients increased numbers of myogenic cells and increased the size of muscle fibers. Klotho also acted directly on macrophages, stimulating their secretion of TNFα. Because TNFα is a muscle mitogen, we tested whether the pro-proliferative effects of Klotho on muscle cells were mediated by TNFα and found that increased proliferation caused by Klotho was reduced by anti-TNFα. Collectively, these data show that pro-inflammatory cytokines contribute to silencing of Klotho in dystrophic muscle, but increase Klotho expression by macrophages. Our findings also show that macrophage-derived Klotho can promote muscle regeneration by expanding populations of muscle stem cells and increasing muscle fiber growth in dystrophic muscle.

Klotho protects the heart from hyperglycemia-induced injury by inactivating ROS and NF-κB-mediated inflammation both in vitro and in vivo

Cardiac inflammation and oxidative stress play a key role in the pathogenesis of diabetic cardiomyopathy (DCM). The anti-aging protein Klotho has been found to protect cells from inflammation and oxidative stress. The current study aimed to explore the cardioprotective effects of Klotho on DCM and the underlying mechanisms. H9c2 cells and neonatal cardiomyocytes were incubated with 33mM glucose in the presence or absence of Klotho. Klotho pretreatment effectively inhibited high glucose-induced inflammation, ROS generation, apoptosis, mitochondrial dysfunction, fibrosis and hypertrophy in both H9c2 cells and neonatal cardiomyocytes. In STZ-induced type 1 diabetic mice, intraperitoneal injection of Klotho at 0.01mg/kg per 48h for 3months completely suppressed cardiac inflammatory cytokines and oxidative stress and prevented cardiac cell death and remodeling, which subsequently improved cardiac dysfunction without affecting hyperglycemia. This study revealed that Klotho may exert its protective effects by augmenting nuclear factor erythroid 2-related factor 2 (Nrf2) expression and inactivating nuclear factor κB (NF-κB) activation both in vitro and in vivo. Thus, this work demonstrated for the first time that the anti-aging protein Klotho may be a potential therapeutic agent to treat DCM by inhibiting oxidative stress and inflammation. We also demonstrated the critical roles of the Nrf2 and NF-κB pathways in diabetes-stimulated cardiac injuries and indicated that they may be key therapeutic targets for diabetic complications.

Klotho gene expression decreases in peripheral blood mononuclear cells (PBMCs) of patients with relapsing-remitting multiple sclerosis

BACKGROUND

we recently showed that a hypothesized anti-aging and anti-inflammatory protein, namely Klotho, may contribute to the etiology and/or pathogenesis of multiple sclerosis (MS). In addition, Klotho function and its gene expression are dependent on inflammatory pathways. Accordingly, the aim of this study was to investigate the Klotho gene expression within peripheral blood mononuclear cells (PBMCs) of patients with MS.

METHODS

Altogether, 30 patients with relapsing-remitting MS (RRMS) along with 30 age and sex-matched healthy individuals were enrolled in this study. Blood samples were obtained from all participants and then PBMCs were isolated. The quantitative Real-Time PCR was carried out for Klotho mRNA derived from PBMCs.

RESULTS

The results showed that klotho gene expression in the PBMCs of patients with RRMS is nearly 2.5-fold less than healthy individuals (P=0.0006).

CONCLUSION

This is the first study demonstrating a possible role of Klotho in the PBMCs of MS patients.