Patients with transfusion-dependent thalassemia (TDT) show disorders in calcium metabolism. The α-klotho protein is predominantly expressed in tissues that are involved in calcium homeostasis, and lowered levels are associated with bone disease. Aim of the study. To study the associations between low α-klotho status and calcium metabolism in relation to iron status in children with TDT. Methods. α-klotho, calcium, parathyroid hormone (PTH), calcyphosin, vitamin D3, phosphorous, fibroblast growth factor receptor 2 (FGFR2), as well as iron and erythron biomarkers were measured in 60 children with TDT and 30 healthy control children. Results. A meaningful part of TDT patients showed lowered α-klotho levels, and those children also showed low serum total and ionized calcium concentrations. TDT patients showed increased PTH, FGFR2, and calcyphosin and lowered vitamin D3 as compared with healthy children. The α-klotho levels were significantly correlated with total and ionized calcium (positively) and with iron overload biomarkers and the number of blood transfusions (inversely). Partial Least Squares path analysis showed that 40.1% of the variance in serum total calcium could be explained by the regression on α-klotho, vitamin D3 (both positively), and calcyphosin (inversely) and that the effects of the latter are mediated by iron overload and the number of blood transfusions. Conclusion. In TDT, iron overload and its consequences may induce lowered levels of α-klotho which in turn may lead to lower calcium thereby explaining at least in part the effects of TDT on bone metabolism including spontaneous pathological fractures, osteoporosis, osteopenia, and skeletal deformities.

The problem of increasing life expectancy is solved with the help of many medical and social areas. It has been established that piRNAs and miRNAs can significantly modify the expression of protein-coding genes by suppressing the translation process. The aim of this work was to establish the possibility of binding piRNAs and miRNAs with mRNA of the KLOTHO and FGF23 genes, which promote health and increase life expectancy through participation in key metabolic processes. We used the MirTarget program, which determines the quantitative characteristics of complementary interactions of all piRNAs and miRNAs nucleotides with mRNA of the genes. piR-44682, piR-1940042, piR-3008660, piR-3215034, piR-6885965, piR-7980636 and one miRNA (ID00756.3p-miR) binding to the mRNA of the KLOTHO gene were found in one cluster of binding sites (BSs). piRNA-6890096 interacted with the mRNA of KLOTHO gene in a fully complementary manner using only canonical nucleotides. Among 17494 human genes, target genes interacting with five piRNAs that bind to the mRNA of KLOTHO gene were identified. mRNA of the AFF2, BCL2L11, CPT1A, DAZAP1, NDRG3, SKIDA1, WBP4, ZIC5, ZSWIM6 genes interacted with piR-3215034 and piR-6885965, which formed clusters of BSs located in 5'UTR, CDS and 3'UTR. The piR-576442, piR-1501557, piR-1845735, piR-2069834, and piR-3029987 had BSs in the mRNAs of the FGF23 gene, located only in the 3'UTR. It is proposed to use piRNAs and miRNAs as regulators of the expression of KLOTHO and FGF23 anti-aging genes.

Klotho (KL) is a glycosyl hydrolase and aging-suppressor gene. Stress is a risk factor for depression and anxiety that are highly comorbid with each other. The aim of this study was to determine KL is regulated by estrogen and plays an important role in sex differences in stress resilience. Our results showed that KL was regulated by estrogen in rat hippocampal neurons in vivo and in vitro and was essential for estrogen-mediated increase in the number of presynaptic vesicular glutamate transporter 1 (Vglut1) positive clusters on the dendrites of hippocampal neurons. The role of KL in sex differences in stress responses was examined in rats using three-week chronic unpredictable mild stress (CUMS). CUMS produced a deficit in spatial learning and memory, anhedonic-like and anxiety-like behaviors in male but not female rats, which was accompanied by a reduction in KL protein levels in the hippocampus of male, but not female rats. This demonstrated the resilience of female rats to CUMS. Interestingly, knockdown of KL protein levels in the rat hippocampus of both sexes caused a decrease in stress resilience in both sexes, especially in female rats. These results suggest that regulation of KL by estrogen plays an important role in estrogen-mediated synapse formation, and KL plays a critical role in the sex differences in cognitive deficit, anhedonic-like and anxiety-like behaviors induced by chronic stress in rats, highlighting an important role of KL in sex differences in stress resilience.

The α-Klotho protein (hereafter Klotho) is an obligate coreceptor for fibroblast growth factor 23 (FGF23). It is produced in the kidneys, brain and other sites. Klotho insufficiency causes hyperphosphatemia and other anomalies. Importantly, it is associated with chronic pathologies (often age-related) that have an inflammatory component. This includes atherosclerosis, diabetes and Alzheimer’s disease. Its mode of action in these diseases is not well understood, but it inhibits or regulates multiple major pathways. Klotho has a membrane form, and a soluble form (s-Klotho). Cytosolic Klotho is postulated but not well characterized. s-Klotho has endocrine properties that are incompletely elucidated. It binds to the FGF receptor 1c (FGFR1c) that is widely expressed (including endothelial cells). It also attaches to soluble FGF23, and FGF23/Klotho binds to FGFRs. Thus, s-Klotho might be a roaming FGF23 coreceptor, but it has other functions. Notably, Klotho (cell-bound or soluble) counteracts inflammation, and appears to mitigate related aging (inflammaging). It inhibits NF-κB and the NLRP3 inflammasome. This inflammasome requires priming by NF-κB, and produces active IL-1β, membrane pores and cell death (pyroptosis). In accord, Klotho countered inflammation and cell injury induced by toxins, damage-associated molecular patterns (DAMPs), cytokines, and reactive oxygen species (ROS). s-Klotho also blocks the TGF-β receptor and Wnt ligands, which lessens fibrotic disease. Low Klotho is associated with loss of muscle mass (sarcopenia), as occurs in aging and chronic diseases. s-Klotho counters the inhibitory effects of myostatin and TGF-β on muscle, reduces inflammation, and improves muscle repair following injury. Inhibition of TGF-β and other factors may also be protective in diabetic retinopathy and age-related macular degeneration (AMD). This review examines Klotho functions especially as related to inflammation, and potential applications.

Oxidative stress driven by several environmental and local airway factors associated with chronic obstructive bronchiolitis, a hallmark feature of COPD, plays a crucial role in the disease pathomechanism. Unbalance between oxidants and antioxidant defense mechanisms not only amplifies the local inflammatory processes, but it also worsens cardiovascular health and contribute to the COPD related cardiovascular dysfunctions and mortality. The current review summarizes recent developments in our understanding of different mechanisms contributing to oxidative stress and its countermeasures with special attention to those that link local and systemic processes. Major regulatory mechanisms orchestrating these pathways are also introduced together with some suggestions for further research on the field.

The farnesoid X receptor (FXR)/βKlotho/fibroblast growth factors (FGFs) pathway is crucial for maintaining the intestinal barrier and preventing colorectal cancer (CRC). We used an FXR ago-nist, GW4064, and FXR knockout (KO) mice to investigate the role of FXR/Klothos/FGFs pathways in lipopolysaccharide (LPS)-induced intestinal barrier dysfunction and colon carcinogenesis. The results showed that upregulation of FXR in enterocytes effectively ameliorated intestinal tight junction markers (claudin1, Zonula occludens-1), inflammation, and bile acid levels, thereby protecting mice from intestinal barrier dysfunction and colon carcinogenesis. GW4064 treatment increased FXR, αKlotho, βKlotho, FGF19, FGF21, and FGF23 in wild-type mice exposed to LPS, while FXR KO mice had decreased levels. FXR KO mice exhibited elevated colon cancer markers (β-catenin, LGR5, CD44, CD34, Cyclin D1) under LPS, underscoring the pivotal role of FXR in inhibiting the development of colon tumorigenesis. The varying gut microbiota responses in FXR KO mice versus wild-type mice post-LPS exposure emphasize the pivotal role of FXR in pre-serving intestinal microbial health, involving Bacteroides thetaiotaomicron, Bacteroides acidifaciens, and Helicobacter hepaticus. Our study validates the effectiveness of GW4064 in alleviating LPS-induced disruptions to the intestinal barrier and colon carcinogenesis, emphasizing the importance of the FXR/αKlotho/βKlotho/FGFs pathway and the interplay between bile acids and gut microbiota.