Human placenta-derived mesenchymal stem cells ameliorate diabetic kidney disease by modulating the T helper 17 cell/ regulatory T-cell balance through the programmed death 1 / programmed death-ligand 1 pathway.

AIM: To investigate the therapeutic effects and immunomodulatory mechanisms of human placenta-derived mesenchymal stem cells (PMSCs) in diabetic kidney disease (DKD). METHODS: Streptozotocin-induced DKD rats were administered an equivalent volume of saline or PMSCs (1 × 106 in 2 mL phosphate-buffered saline per rat) for 3 weeks. Eight weeks after treatment, we examined the biochemical parameters in the blood and urine, the ratio of T helper 17 cells (Th17) and regulatory T cells (Treg) in the blood, cytokine levels in the kidney and blood, and renal histopathological changes. In addition, we performed PMSC tracing and renal transcriptomic analyses using RNA-sequencing. Finally, we determined whether PMSCs modulated the Th17/Treg balance by upregulating programmed death 1 (PD-1) in vitro. RESULTS: The PMSCs significantly improved renal function, which was assessed by serum creatinine levels, urea nitrogen, cystatin C levels, urinary albumin-creatinine ratio, and the kidney index. Further, PMSCs alleviated pathological changes, including tubular vacuolar degeneration, mesangial matrix expansion, and glomerular filtration barrier injury. In the DKD rats in our study, PMSCs were mainly recruited to immune organs, rather than to the kidney or pancreas. PMSCs markedly promoted the Th17/Treg balance and reduced the levels of pro-inflammatory cytokines (interleukin [IL]-17A and IL-1ß) in the kidney and blood of DKD rats. In vitro experiments showed that PMSCs significantly reduced the proportion of Th17 cells and increased the proportion of Treg cells by upregulating PD-1 in a cell-cell contact manner and downregulating programmed death-ligand 1 (PD-L1) expression in PMSCs, which reversed the Th17/Treg balance. CONCLUSION: We found that PMSCs improved renal function and pathological damage in DKD rats and modulated Th17/Treg balance through the PD-1/PD-L1 pathway. These findings provide a novel mechanism and basis for the clinical use of PMSCs in the treatment of DKD.

Landscape of infiltrating immune cells and related genes in diabetic kidney disease.

INTRODUCTION: Diabetic kidney disease (DKD) is one of the prominent microvascular complications of diabetes and the leading cause of end-stage renal disease. Inflammation plays a crucial role in the development and progression of DKD. Currently, only a few studies depict the landscape of infiltrating immune cells and their potential regulatory network in DKD. To gain a better understanding of the role of immune cells in the renal microenvironment, we sought to reveal the profile of infiltrating immune cells and their potential regulatory network in DKD. METHODS: We obtained the transcriptomes and the corresponding clinical data of 19 DKD and 25 control samples from the Gene Expression Omnibus and Nephroseq databases, respectively. Thereafter, we conducted an analysis on the infiltrating immune cells and identified immune-related differentially expressed genes through bioinformatics. Finally, correlation analyses among immune cells, immune genes, and clinical manifestations were performed, and differentially infiltrating immune cell subsets were verified through multiplex immunofluorescence staining. RESULTS: We demonstrated the landscape of infiltrating immune cells in patients with DKD and identified the top five hub immune regulatory genes (C3, IL7R, TYROBP, BMP2, and CXCL6). Three of the core genes (C3, BMP2, and CXCL6) were significantly correlated with the estimated glomerular filtration rate. Through multiplex immunofluorescence staining, we verified that macrophage numbers were remarkably elevated, whereas Treg cells were remarkably reduced in diabetic kidney tissues. Th2 cells were scarce in the kidney tissue. CONCLUSION: Collectively, our findings shed light on new, possible therapeutic strategies for DKD, from an immune microenvironment perspective.

Placenta-derived mesenchymal stem cells protect against diabetic kidney disease by upregulating autophagy-mediated SIRT1/FOXO1 pathway.

Diabetic kidney disease (DKD) is a common chronic microvascular complication of diabetes mellitus. Although studies have indicated the therapeutic potential of mesenchymal stem cells (MSCs) for DKD, the underlying molecular mechanisms remain unclear. Herein, we explored the renoprotective effect of placenta-derived MSCs (P-MSCs) and the potential mechanism of SIRT1/FOXO1 pathway-mediated autophagy in DKD. The urine microalbumin/creatinine ratio was determined using ELISA, and renal pathological changes were detected by special staining techniques. Immunofluorescence was used for detecting the renal tissue expression of podocin and nephrin; immunohistochemistry for the renal expression of autophagy-related proteins (LC3, Beclin-1, SIRT1, and FOXO1); and western blotting and PCR for the expression of podocyte autophagy- and pathway-related indicators. We found that P-MSCs ameliorated renal tubular injury and glomerular mesangial matrix deposition and alleviated podocyte damage in DKD rats. PMSCs enhanced autophagy levels and increased SIRT1 and FOXO1 expression in DKD rat renal tissue, whereas the autophagy inhibitor 3-methyladenine significantly attenuated the renoprotective effect of P-MSCs. P-MSCs improved HG-induced Mouse podocyte clone5(MPC5)injury, increased podocyte autophagy, and upregulated SIRT1 and FOXO1 expression. Moreover, downregulation of SIRT1 expression blocked the P-MSC-mediated enhancement of podocyte autophagy and improvement of podocyte injury. Thus, P-MSCs can significantly improve renal damage and reduce podocyte injury in DKD rats by modulating the SIRT1/FOXO1 pathway and enhancing podocyte autophagy.

Placental Mesenchymal Stem Cells Alleviate Podocyte Injury in Diabetic Kidney Disease by Modulating Mitophagy via the SIRT1-PGC-1alpha-TFAM Pathway.

The use of mesenchymal stem cells (MSCs) has become a new strategy for treating diabetic kidney disease (DKD). However, the role of placenta derived mesenchymal stem cells (P-MSCs) in DKD remains unclear. This study aims to investigate the therapeutic application and molecular mechanism of P-MSCs on DKD from the perspective of podocyte injury and PINK1/Parkin-mediated mitophagy at the animal, cellular, and molecular levels. Western blotting, reverse transcription polymerase chain reaction, immunofluorescence, and immunohistochemistry were used to detect the expression of podocyte injury-related markers and mitophagy-related markers, SIRT1, PGC-1α, and TFAM. Knockdown, overexpression, and rescue experiments were performed to verify the underlying mechanism of P-MSCs in DKD. Mitochondrial function was detected by flow cytometry. The structure of autophagosomes and mitochondria were observed by electron microscopy. Furthermore, we constructed a streptozotocin-induced DKD rat model and injected P-MSCs into DKD rats. Results showed that as compared with the control group, exposing podocytes to high-glucose conditions aggravated podocyte injury, represented by a decreased expression of Podocin along with increased expression of Desmin, and inhibited PINK1/Parkin-mediated mitophagy, manifested as a decreased expression of Beclin1, the LC3II/LC3I ratio, Parkin, and PINK1 associated with an increased expression of P62. Importantly, these indicators were reversed by P-MSCs. In addition, P-MSCs protected the structure and function of autophagosomes and mitochondria. P-MSCs increased mitochondrial membrane potential and ATP content and decreased the accumulation of reactive oxygen species. Mechanistically, P-MSCs alleviated podocyte injury and mitophagy inhibition by enhancing the expression of the SIRT1-PGC-1α-TFAM pathway. Finally, we injected P-MSCs into streptozotocin-induced DKD rats. The results revealed that the application of P-MSCs largely reversed the markers related to podocyte injury and mitophagy and significantly increased the expression of SIRT1, PGC-1α, and TFAM compared with the DKD group. In conclusion, P-MSCs ameliorated podocyte injury and PINK1/Parkin-mediated mitophagy inhibition in DKD by activating the SIRT1-PGC-1α-TFAM pathway.

The value of neutrophil-to-lymphocyte ratio combined with the thyroid imaging reporting and data system in the diagnosis of the nature of thyroid nodules.

OBJECTIVE: The aim of this study was to investigate the diagnostic value of peripheral blood neutrophil-to-lymphocyte ratio (NLR) combined with the thyroid imaging reporting and data system (TIRADS) for benign and malignant thyroid nodules. METHODS: A total of 585 adults were enrolled in the study. The receiver operating characteristic curves were used to determine the optimal cut-off values for NLR and Kwak TIRADS (K-TIRADS) grades, which were 1.87 and 4a, respectively. Thyroid nodules were scored as follows: NLR-K-TIRADS score is 2 (both elevated K-TIRADS grade and NLR), NLR-K-TIRADS score is 1 (one of these was elevated) and NLR-k-TIRADS score is 0 (neither were elevated). RESULTS: The proportions of malignant nodules with NLR-K-TIRADS scores of 2, 1 and 0 were 98.59%, 69.62% and 10.19%, and the difference was statistically significant (p < 0.001). In terms of the sensitivity of diagnosis of malignant nodules, NLR-K-TIRADS 1 tends to increase relative to K-TIRADS grades ≥ 4a; in terms of specificity and positive predictive value for the diagnosis of malignant nodules, NLR-K-TIRADS 2 was significantly higher than K-TIRADS grades ≥ 4a (all p < 0.05). CONCLUSIONS: NLR combined with K-TIRADS grades may be a novel method for screening benign and malignant thyroid nodules.

Peripheral Blood Inflammatory Markers Can Predict Benign and Malignant Thyroid Nodules.

Objective: Inflammation is related to the occurrence and development of various cancers. This study was designed to explore the role of peripheral blood platelet count, neutrophil-lymphocyte ratio (NLR), platelet count-lymphocyte count ratio (PLR), systemic inflammation index (SII), and other inflammatory markers in predicting benign and malignant Thyroid Imaging Reporting and Data System (TI-RADS) grade 3 thyroid nodules. Methods: In this retrospective study, 514 patients with TI-RADS grade 3 thyroid nodules were enrolled. According to the pathological results, the patients were divided into the benign and malignant nodule groups. We compared the clinical characteristics between the two groups and analysed the influencing factors for malignant thyroid nodules by univariate and stepwise multivariate logistic regression analyses and then analysed the cutoff value of each influencing factor according to the receiver operating characteristic curve. Results: The leukocyte count, neutrophil count, platelet count, NLR, PLR, and SII of the malignant nodule group were significantly higher than those of the benign nodule group (P < 0.05), the age and the diameter of nodule of the malignant nodule group were significantly smaller than those of the benign nodule group (P < 0.05). After excluding the influence of confounding factors, SII (odds ratio (OR) = 1.006; 95% confidence interval (CI) = 1.003-1.008; P < 0.001), PLR (odds ratio (OR) = 0.981; 95% confidence interval (CI) = 0.981-0.992; P < 0.05), leukocyte count (odds ratio (OR) = 0.654; 95% confidence interval (CI) = 0.466-0.892; P < 0.05), and age (OR = 0.969; 95% CI = 0.954-0.985; P < 0.001) were independent risk factors for malignant thyroid nodules, and the cutoff value of SII and PLR in predicting benign and malignant thyroid nodules were 545.63 × 109/L and 138.63. Conclusion: This study showed that peripheral blood SII, PLR, leukocyte count and age were independent risk factors for malignant thyroid nodules, and the combination of these can better predict benign and malignant thyroid nodules, which can further guide the diagnosis and treatment of TI-RADS grade 3 thyroid nodules.

ISCA2 deficiency leads to heme synthesis defects and impaired erythroid differentiation in K562 cells by indirect ROS-mediated IRP1 activation.

Iron­sulfur (Fe-S) clusters have been shown to play important roles in various cellular physiological process. Iron­sulfur cluster assembly 2 (ISCA2) is a vital component of the [4Fe-4S] cluster assembly machine. Several studies have shown that ISCA2 is highly expressed during erythroid differentiation. However, the role and specific regulatory mechanisms of ISCA2 in erythroid differentiation and erythroid cell growth remain unclear. RNA interference was used to deplete ISCA2 expression in human erythroid leukemia K562 cells. The proliferation, apoptosis, and erythroid differentiation ability of the cells were assessed. We show that knockdown of ISCA2 has profound effects on [4Fe-4S] cluster formation, diminishing mitochondrial respiratory chain complexes, leading to reactive oxygen species (ROS) accumulation and mitochondrial damage, inhibiting cell proliferation. Excessive ROS can inhibit the activity of cytoplasmic aconitase (ACO1) and promote ACO1, a bifunctional protein, to perform its iron-regulating protein 1(IRP1) function, thus inhibiting the expression of 5'-aminolevulinate synthase 2 (ALAS2), which is a key enzyme in heme synthesis. Deficiency of ISCA2 results in the accumulation of iron divalent. In addition, the combination of excessive ferrous iron and ROS may lead to damage of the ACO1 cluster and higher IRP1 function. In brief, ISCA2 deficiency inhibits heme synthesis and erythroid differentiation by double indirect downregulation of ALAS2 expression. We conclude that ISCA2 is essential for normal functioning of mitochondria, and is necessary for erythroid differentiation and cell proliferation.