Metabolic Imbalance of Homocysteine and Hydrogen Sulfide in Kidney Disease

2018 ◽  
Vol 25 (3) ◽  
pp. 367-377 ◽  
Author(s):  
Karmin O ◽  
Yaw L. Siow

Homocysteine (Hcy) and hydrogen sulfide (H2S) are important molecules produced during the metabolism of sulfur-containing amino acids. Hcy metabolism is central to the supply of methyl groups that are essential for biological function. Hcy can be either regenerated to methionine or metabolized to cysteine, a precursor for glutathione synthesis. Cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) play a crucial role in metabolizing Hcy to cysteine through the transsulfuration pathway. These two enzymes are also responsible for H2S generation through desulfuration reactions. H2S, at physiological levels serves as a gaseous mediator and has multifaceted effects. Metabolic imbalance of Hcy and H2S has been implicated in pathological conditions including oxidative stress, inflammation, cardiovascular and cerebral dysfunction, fatty liver disease and ischemiareperfusion injury. Organs such as liver, kidney, gut and pancreas contain all the enzymes that are required for Hcy metabolism. The kidney plays an important role in removing Hcy from the circulation. Hyperhomocysteinemia, a condition of elevated blood Hcy level, is a common clinical finding in patients with chronic kidney disease (CKD) or acute kidney injury (AKI), the latter is often caused by ischemia-reperfusion. This paper reviews exiting literatures regarding (1) the role of kidney in regulating Hcy and H2S metabolism; (2) disruption of sulfur-containing amino acid metabolism during ischemiareperfusion; (3) impact of metabolic imbalance of Hcy and H2S on kidney function. Better understanding of molecular mechanisms that regulate Hcy and H2S metabolism under physiological and pathophysiological conditions will help improve therapeutic strategies for patients with kidney disease or other organ injuries.

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jing-Ying Zhao ◽  
Yu-Bin Wu

Endoplasmic reticulum stress (ERS) is strongly associated with acute kidney injury (AKI) to chronic kidney disease (CKD) transition. Huaier extract (HE) protects against kidney injury; albeit, the underlying mechanism is unknown. We hypothesized that HE reduces kidney injury by inhibiting ERS. In this study, using an AKI-CKD mouse model of ischemia-reperfusion injury (IRI), we evaluated the effect of HE on AKI-CKD transition. We also explored the underlying molecular mechanisms in this animal model and in the HK-2 human kidney cell line. The results showed that HE treatment improved the renal function, demonstrated by a significant decrease in serum creatinine levels after IRI. HE appreciably reduced the degree of kidney injury and fibrosis and restored the expression of the microRNA miR-1271 after IRI. Furthermore, HE reduced the expression of ERS markers glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) and inhibited apoptosis in the IRI group. This in vivo effect was supported by in vitro results in which HE inhibited apoptosis and decreased the expression of CHOP and GRP78 induced by ERS. We demonstrated that CHOP is a target of miR-1271. In conclusion, HE reduces kidney injury, probably by inhibiting apoptosis and decreasing the expression of GRP78 and CHOP via miR-1271 upregulation.


2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Chenguang Ding ◽  
Xiaoming Ding ◽  
Jin Zheng ◽  
Bo Wang ◽  
Yang Li ◽  
...  

Abstract Renal tubular cell death is the key factor of the pathogenesis of ischemia/reperfusion (I/R) kidney injury. Ferroptosis is a type of regulated cell death (RCD) found in various diseases. However, the underlying molecular mechanisms related to ferroptosis in renal I/R injury remain unclear. In the present study, we investigated the regulatory role of microRNAs on ferroptosis in I/R-induced renal injury. We established the I/R-induced renal injury model in rats, and H/R induced HK-2 cells injury in vitro. CCK-8 was used to measure cell viability. Fe2+ and ROS levels were assayed to evaluate the activation of ferroptosis. We performed RNA sequencing to profile the miRNAs expression in H/R-induced injury and ferroptosis. Western blot analysis was used to detect the protein expression. qRT-PCR was used to detect the mRNA and miRNA levels in cells and tissues. We further used luciferase reporter assay to verify the direct targeting effect of miRNA. We found that ischemia/reperfusion-induced ferroptosis in rat’s kidney. We identified that miR-182-5p and miR-378a-3p were upregulated in the ferroptosis and H/R-induced injury, and correlates reversely with glutathione peroxidases 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression in renal I/R injury tissues, respectively. In vitro studies showed that miR-182-5p and miR-378a-3p induced ferroptosis in cells. We further found that miR-182-5p and miR-378a-3p regulated the expression of GPX4 and SLC7A11 negatively by directly binding to the 3′UTR of GPX4 and SLC7A11 mRNA. In vivo study showed that silencing miR-182-5p and miR-378a-3p alleviated the I/R-induced renal injury in rats. In conclusion, we demonstrated that I/R induced upregulation of miR-182-5p and miR-378a-3p, leading to activation of ferroptosis in renal injury through downregulation of GPX4 and SLC7A11.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Yaqi Shen ◽  
Zhuqing Shen ◽  
Shanshan Luo ◽  
Wei Guo ◽  
Yi Zhun Zhu

Hydrogen sulfide (H2S) is now recognized as a third gaseous mediator along with nitric oxide (NO) and carbon monoxide (CO), though it was originally considered as a malodorous and toxic gas. H2S is produced endogenously from cysteine by three enzymes in mammalian tissues. An increasing body of evidence suggests the involvement of H2S in different physiological and pathological processes. Recent studies have shown that H2S has the potential to protect the heart against myocardial infarction, arrhythmia, hypertrophy, fibrosis, ischemia-reperfusion injury, and heart failure. Some mechanisms, such as antioxidative action, preservation of mitochondrial function, reduction of apoptosis, anti-inflammatory responses, angiogenic actions, regulation of ion channel, and interaction with NO, could be responsible for the cardioprotective effect of H2S. Although several mechanisms have been identified, there is a need for further research to identify the specific molecular mechanism of cardioprotection in different cardiac diseases. Therefore, insight into the molecular mechanisms underlying H2S action in the heart may promote the understanding of pathophysiology of cardiac diseases and lead to new therapeutic targets based on modulation of H2S production.


2020 ◽  
Author(s):  
Caitriona M. McEvoy ◽  
Sergi Clotet-Freixas ◽  
Tomas Tokar ◽  
Chiara Pastrello ◽  
Shelby Reid ◽  
...  

AbstractNormothermic ex-vivo kidney perfusion (NEVKP) results in significantly improved graft function in porcine auto-transplant models of DCD injury compared to static cold storage (SCS); however, the molecular mechanisms underlying these beneficial effects remain unclear. We performed an unbiased proteomics analysis of 28 kidney biopsies obtained at 3 time points from pig kidneys subjected to 30-minutes of warm ischemia, followed by 8 hours of NEVKP or SCS, and auto-transplantation. 70/6593 proteins quantified were differentially expressed between NEVKP and SCS groups (FDR<0.05). Proteins increased in NEVKP mediated key metabolic processes including fatty acid ß-oxidation, the TCA-cycle and oxidative phosphorylation. Comparison of our findings with external datasets of ischemia-reperfusion, and other models of kidney injury confirmed that 47 of our proteins represent a common signature of kidney injury reversed or attenuated by NEVKP. We validated key metabolic proteins (ETFB, CPT2) by immunoblotting. Transcription factor databases identified PPARGC1A, PPARA/G/D and RXRA/B as the upstream regulators of our dataset, and we confirmed their increased expression in NEVKP with RT-PCR. The proteome-level changes observed in NEVKP mediate critical metabolic pathways that may explain the improved graft function observed. These effects may be coordinated by PPAR-family transcription factors, and may represent novel therapeutic targets in ischemia-reperfusion injury.


2015 ◽  
Vol 55 (3) ◽  
pp. 151-183 ◽  
Author(s):  
Casper Kierulf-Lassen ◽  
Gertrude J. Nieuwenhuijs-Moeke ◽  
Nicoline V. Krogstrup ◽  
Mihai Oltean ◽  
Bente Jespersen ◽  
...  

Ischemia-reperfusion injury is the leading cause of acute kidney injury in a variety of clinical settings such as renal transplantation and hypovolemic and/or septic shock. Strategies to reduce ischemia-reperfusion injury are obviously clinically relevant. Ischemic conditioning is an inherent part of the renal defense mechanism against ischemia and can be triggered by short periods of intermittent ischemia and reperfusion. Understanding the signaling transduction pathways of renal ischemic conditioning can promote further clinical translation and pharmacological advancements in this era. This review summarizes research on the molecular mechanisms underlying both local and remote ischemic pre-, per- and postconditioning of the kidney. The different types of conditioning strategies in the kidney recruit similar powerful pro-survival mechanisms. Likewise, renal ischemic conditioning mobilizes many of the same protective signaling pathways as in other organs, but differences are recognized.


2017 ◽  
Vol 114 (47) ◽  
pp. 12608-12613 ◽  
Author(s):  
Bing-Qing Deng ◽  
Ying Luo ◽  
Xin Kang ◽  
Chang-Bin Li ◽  
Christophe Morisseau ◽  
...  

Acute kidney injury (AKI) causes severe morbidity and mortality for which new therapeutic strategies are needed. Docosahexaenoic acid (DHA), arachidonic acid (ARA), and their metabolites have various effects in kidney injury, but their molecular mechanisms are largely unknown. Here, we report that 14 (15)-epoxyeicosatrienoic acid [14 (15)-EET] and 19 (20)-epoxydocosapentaenoic acid [19 (20)-EDP], the major epoxide metabolites of ARA and DHA, respectively, have contradictory effects on kidney injury in a murine model of ischemia/reperfusion (I/R)-caused AKI. Specifically, 14 (15)-EET mitigated while 19 (20)-EDP exacerbated I/R kidney injury. Manipulation of the endogenous 19 (20)-EDP or 14 (15)-EET by alteration of their degradation or biosynthesis with selective inhibitors resulted in anticipated effects. These observations are supported by renal histological analysis, plasma levels of creatinine and urea nitrogen, and renal NGAL. The 14 (15)-EET significantly reversed the I/R-caused reduction in glycogen synthase kinase 3β (GSK3β) phosphorylation in murine kidney, dose-dependently inhibited the hypoxia/reoxygenation (H/R)-caused apoptosis of murine renal tubular epithelial cells (mRTECs), and reversed the H/R-caused reduction in GSK3β phosphorylation in mRTECs. In contrast, 19 (20)-EDP dose-dependently promoted H/R-caused apoptosis and worsened the reduction in GSK3β phosphorylation in mRTECs. In addition, 19 (20)-EDP was more metabolically stable than 14 (15)-EET in vivo and in vitro. Overall, these epoxide metabolites of ARA and DHA function conversely in I/R-AKI, possibly through their largely different metabolic stability and their opposite effects in modulation of H/R-caused RTEC apoptosis and GSK3β phosphorylation. This study provides AKI patients with promising therapeutic strategies and clinical cautions.


Blood ◽  
2010 ◽  
Vol 116 (9) ◽  
pp. 1397-1404 ◽  
Author(s):  
Eliot C. Heher ◽  
Nelson B. Goes ◽  
Thomas R. Spitzer ◽  
Noopur S. Raje ◽  
Benjamin D. Humphreys ◽  
...  

Plasma cell dyscrasias are frequently encountered malignancies often associated with kidney disease through the production of monoclonal immunoglobulin (Ig). Paraproteins can cause a remarkably diverse set of pathologic patterns in the kidney and recent progress has been made in explaining the molecular mechanisms of paraprotein-mediated kidney injury. Other recent advances in the field include the introduction of an assay for free light chains and the use of novel antiplasma cell agents that can reverse renal failure in some cases. The role of stem cell transplantation, plasma exchange, and kidney transplantation in the management of patients with paraprotein-related kidney disease continues to evolve.


Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1754
Author(s):  
Itaru Monno ◽  
Yoshio Ogura ◽  
Jing Xu ◽  
Daisuke Koya ◽  
Munehiro Kitada

Lifestyle improvement, including through exercise, has been recognized as an important mode of therapy for the suppression of diabetic kidney disease (DKD). However, the detailed molecular mechanisms by which exercise exerts beneficial effects in the suppression of DKD have not yet been fully elucidated. In this study, we investigate the effects of treadmill exercise training (TET) for 8 weeks (13 m/min, 30 min/day, 5 days/week) on kidney injuries of type 2 diabetic male rats with obesity (Wistar fatty (fa/fa) rats: WFRs) at 36 weeks of age. TET significantly suppressed the levels of albuminuria and urinary liver-type fatty-acid-binding protein (L-FABP), tubulointerstitial fibrosis, inflammation, and oxidative stress in the kidneys of WFRs. In addition, TET mitigated excessive apoptosis and restored autophagy in the renal cortex, as well as suppressed the development of morphological abnormalities in the mitochondria of proximal tubular cells, which were also accompanied by the restoration of AMP-activated kinase (AMPK) activity and suppression of the mechanistic target of rapamycin complex 1 (mTORC1). In conclusion, TET ameliorates diabetes-induced kidney injury in type 2 diabetic fatty rats.


Nephron ◽  
2021 ◽  
pp. 1-4
Author(s):  
David P. Basile ◽  
Jason A. Collett

This review focuses on the potential mediation in the acute kidney injury (AKI)-to-chronic kidney disease (CKD) transition by lymphocytes. We highlight evidence that lymphocytes, particularly Th17 cells, modulate the severity of both acute injury and chronic kidney disease. Th17 cells are strongly influenced by the activity of the store-operated Ca<sup>2+</sup>channel Orai1, which is upregulated on lymphocytes in animal models of AKI. Inhibition of this channel attenuates both acute and chronic kidney injury in rodent models. In addition, Oria1+ cells are increased in peripheral blood of patients with AKI. Similarly, peripheral blood cells manifest an early and sustained increase in Orai1 expression in a rat model of ischemia/reperfusion, suggesting that blood cell Orai1 may represent a marker informing potential Th17 activity in the setting of AKI or the AKI-to-CKD transition.


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