2,8-Dihydroxyadenine-induced nephropathy causes hexosylceramide accumulation with increased mTOR signaling, reduced levels of protective SirT3 expression and impaired renal mitochondrial function

Lyophilized powder of calf bone marrow hydrolysate liposomes improved renal anemia: In vitro and in vivo evaluation

This study aimed to find whether oral administration of calf bone marrow hydrolysate liposomes (CBMHL) can improve renal anemia. Calf bone marrow was defatted, papain hydrolyzed, liposomalized and lyophilized. Its hematopoietic ability was proved by the colony formation experiment of umbilical cord blood hematopoietic stem cells in vitro. The rat model of renal anemia was established by adenine intragastric administration, and different concentrations of CBMHL were intragastricly administrated. Blood routine and serological indexes, transcription levels of hematopoietic factors and renal pathology were detected. From the appearance, redispersability, water content, liposome indexes and stability of Lyophilized powder of CBMHL, it could be concluded that the quality of freeze-dried CBMHL powder under this freeze-drying process was good. Compared with the control group, the burst forming unit-erythroid (BFU-E) in the CBMHL group was larger and the number of colonies increased significantly in the colony formation experiment (P < 0.05). The results of lyophilized powder of CBMHL co-culture with human adipose mesenchymal stem cells (MSCs) and human cytokine-induced killer (CIK) cells showed that the lyophilized powder of CBMHL had no potential toxicity and allergic reaction in vitro. Compared with the Model Group, the red blood cell (RBC) count, hemoglobin (HB) content and hematokrit (HCT) of rats blood routine in the Model+high doses of CBMHL Group (Model+H-CBMHL Group) increased significantly (P < 0.05). Serum erythropoietin (EPO) and glutathione (GSH) levels increased significantly (P < 0.05), while serum creatinine (Cr) levels decreased significantly(P < 0.05). The transcription level of Epo in kidney increased significantly (P < 0.05), the transcription levels of erythropoietin receptor (Epor) in bone marrow and interleukin 6 (Il6) in spleen were significantly increased (P < 0.01). The fragility of red blood cells decreased significantly, and the pathological structure of kidney improved significantly. It was proved that lyophilized powder of CBMHL could effectively enhance the hematopoietic ability of rats with renal anemia and protect the kidney structure and function.

Role of mitochondria in reno-cardiac diseases: A study of bioenergetics, biogenesis, and GSH signaling in disease transition

Acute kidney injury (AKI) and chronic kidney disease (CKD) are global health burdens with rising prevalence. Their bidirectional relationship with cardiovascular dysfunction, manifesting as cardio-renal syndromes (CRS) types 3 and 4, underscores the interconnectedness and interdependence of these vital organ systems. Both the kidney and the heart are critically reliant on mitochondrial function. This organelle is currently recognized as a hub in signaling pathways, with emphasis on the redox regulation mediated by glutathione (GSH). Mitochondrial dysfunction, including impaired bioenergetics, redox, and biogenesis pathways, are central to the progression of AKI to CKD and the development of CRS type 3 and 4. This review delves into the metabolic reprogramming and mitochondrial redox signaling and biogenesis alterations in AKI, CKD, and CRS. We examine the pathophysiological mechanisms involving GSH redox signaling and the AMP-activated protein kinase (AMPK)-sirtuin (SIRT)1/3-peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α) axis in these conditions. Additionally, we explore the therapeutic potential of GSH synthesis inducers in mitigating these mitochondrial dysfunctions, as well as their effects on inflammation and the progression of CKD and CRS types 3 and 4.

SLC25A48 controls mitochondrial choline import and metabolism

Choline is an essential nutrient for the biosynthesis of phospholipids, neurotransmitters, and one-carbon metabolism with a critical step being its import into mitochondria. However, the underlying mechanisms and biological significance remain poorly understood. Here, we report that SLC25A48, a previously uncharacterized mitochondrial inner-membrane carrier protein, controls mitochondrial choline transport and the synthesis of choline-derived methyl donors. We found that SLC25A48 was required for brown fat thermogenesis, mitochondrial respiration, and mitochondrial membrane integrity. Choline uptake into the mitochondrial matrix via SLC25A48 facilitated the synthesis of betaine and purine nucleotides, whereas loss of SLC25A48 resulted in increased production of mitochondrial reactive oxygen species and imbalanced mitochondrial lipids. Notably, human cells carrying a single nucleotide polymorphism on the SLC25A48 gene and cancer cells lacking SLC25A48 exhibited decreased mitochondrial choline import, increased oxidative stress, and impaired cell proliferation. Together, this study demonstrates that SLC25A48 regulates mitochondrial choline catabolism, bioenergetics, and cell survival.

Discovery of 2,8-dihydroxyadenine in HUA patients with uroliths and biomarkers for its associated nephropathy

Currently, it is acknowledged that gout is caused by uric acid (UA). However, some studies have revealed no correlation between gout and UA levels, and growing evidence suggests that 2,8-dihydroxyadenine (2,8-DHA), whose structural formula is similar to UA but is less soluble, may induce gout. Hence, we hypothesized that uroliths from hyperuricemia (HUA) patients, which is closely associated with gout, may contain 2,8-DHA. In this study, 2,8-DHA in uroliths and serum of HUA patients were determined using HPLC. Moreover, bioinformatics was used to investigate the pathogenic mechanisms of 2,8-DHA nephropathy. Subsequently, a mouse model of 2,8-DHA nephropathy established by the gavage administration of adenine, as well as a model of injured HK-2 cells induced by 2,8-DHA were used to explore the pathogenesis of 2,8-DHA nephropathy. Interestingly, 2,8-DHA could readily deposit in the cortex of the renal tubules, and was found in the majority of these HUA patients. Additionally, the differentially expressed genes between 2,8-DHA nephropathy mice and control mice were found to be involved in inflammatory reactions. Importantly, CCL2 and IL-1β genes had the maximum degree, closeness, and betweenness centrality scores. The expressions of CCL2 and IL-1β genes were significantly increased in the serum of 24 HUA patients with uroliths, indicating that they may be significant factors for 2,8-DHA nephropathy. Further analysis illustrated that oxidative damage and inflammation were the crucial processes of 2,8-DHA renal injury, and CCL2 and IL-1β genes were verified to be essential biomarkers for 2,8-DHA nephropathy. These findings revealed further insights into 2,8-DHA nephropathy, and provided new ideas for its diagnosis and treatment.