<b><i>Objective:</i></b> Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells which can suppress T-cell functionality. Herein, we evaluated the functional importance of MDSCs in the context of kidney ischemia-reperfusion injury (IRI) and explored their ability to regulate innate and adaptive immune cell function in this context. <b><i>Methods:</i></b> The differentiation of MDSCs was induced in vitro by treating cells with GM-CSF and interferon (IFN)-γ. In a murine model of renal IRI, serum creatinine and blood urea nitrogen values were measured to monitor kidney function, while histopathological and immunohistochemical approaches were used to assess kidney injury severity. In addition, flow cytometry was employed to assess the phenotypes and apoptosis of kidney cells in these mice. <b><i>Results:</i></b> MDSCs induced by treatment with GM-CSF + IFN-γ could suppress T-cell functionality in vitro<i>.</i> The adoptive transfer of these MDSCs into an IRI mouse model system enhanced kidney damage and impaired renal function following the recruitment of these cells to renal tissues in these mice. Following such adoptive transfer, the relative frequency of MDSCs with a CD11b<sup>+</sup>Ly6G<sup>−</sup>Ly6C<sup>high</sup> monocytic-MDSC phenotype decreased, whereas cells with a CD11b<sup>+</sup>Ly6G<sup>+</sup>Ly6C<sup>low</sup> polymorphonuclear-MDSC phenotype become more prevalent within kidney tissues following IRI. Adoptive transfer also coincided with increased frequencies of macrophages and dendritic cells (DCs) in the kidney tissues. This suggested that M-MDSCs contributed to early-stage renal IRI damage by differentiating into these deleterious cell types. However, MDSC-induced suppression of CD4<sup>+</sup> and CD8<sup>+</sup> T-cell infiltration was not sufficient to prevent the deterioration of renal function in these mice. <b><i>Conclusions:</i></b> Herein, we successfully developed a protocol wherein MDSCs were differentiated in vitro through combination GM-CSF/IFN-γ treatment. When these MDSCs were subsequently adoptively transferred into a murine model of renal IRI, they aggravated kidney damage, likely owing to the differentiation of M-MDSCs into deleterious macrophages and DCs.
Investigate the effect of mild hypothermia on serum inflammatory factor HMGB1 of brain-dead donors, and its significance for renal transplantation recipients. In our hospital between January 2018 and January 2019 up to the standard of brain death donor (aged 18 to 65 years old) prospective cohort study, brain death donor were randomly divided into mild hypothermia group and the non-mild hypothermia group. Serum were collected from donor at different periods, and enzyme-linked immunoassay (ELISA) was used to determine the serum HMGB1 concentration to compare the difference between the 2 donor groups. The early recovery of renal function after renal transplantation was followed up, and the incidence of delayed graft function (DGF) and early recovery of renal function were compared between the 2 groups. The correlation between donor HMGB1 and recipient DGF was analyzed. Between 17 donors in the mild hypothermia group and 17 in the non-mild hypothermia group, there were no statistically significant differences in the age, perioperative urine volume and ICU stay between the 2 groups. After mild hypothermia treatment, serum HMGB1 levels of brain death donors were significantly decreased. While in non-mild hypothermia brain death donor group without treatment, serum HMGB1 was significantly increased. There were no statistically significant differences in age and preoperative creatinine between the 2 recipient groups, including 33 patients in the mild hypothermia group and 34 patients in the non-mild hypothermia group. DGF incidence was lower in mild hypothermia group comparing with non-mild hypothermia group with statistical significance. The levels of HMGB1 from donor before procurement is correlated with the occurrence of DGF of the recipient. Mild hypothermia therapy can reduce the levels of serum HMGB1, improve the function of donor organs. The levels of HMGB1 before donor procurement can be used to predict the occurrence of DGF in kidney transplant recipients. Our study shows that HMGB1 can be potentially used as therapeutic target of early intervention for brain death donors. Furthermore, mild hypothermia therapy can be applied in the maintenance of brain death donors for kidney transplant recipient to improve the successful rate of transplantation.
The inhibition of 5-α reductase type 2 (SRD5A2) by finasteride is commonly used for the management of urinary obstruction resulting from benign prostatic enlargement (BPE). Certain BPE patients showing no SRD5A2 protein expression are resistant to finasteride therapy. Our previous work showed that methylated cytosine-phosphate-guanine (CpG) islands in the SRD5A2 gene might account for the absence or reduction of SRD5A2 protein expression. Here, we found that the expression of the SRD5A2 protein was variable and that weak expression of the SRD5A2 protein (scored 0–100) occurred in 10.0% (4/40) of benign adult prostates. We showed that the expression of SRD5A2 was negatively correlated with DNA methyltransferase 1 (DNMT1) expression. In vitro SRD5A2-negative BPH-1 cells were resistant to finasteride treatment, and SRD5A2 was re-expressed in BPH-1 cells when SRD5A2 was demethylated by 5-Aza-2'-deoxycytidine (5-Aza-CdR) or N-phthalyl-L-tryptophan (RG108). Furthermore, we determined the exact methylation ratios of CpG dinucleotides in a CpG island of SRD5A2 through MassArray quantitative methylation analysis. Ten methylated CpG dinucleotides, including four CpG dinucleotides in the promoter and six CpG dinucleotides in the first exon, were found in a CpG island located from −400 bp to +600 bp in SRD5A2 , which might lead to the silencing of SRD5A2 and the absence or reduction of SRD5A2 protein expression. Finasteride cannot exert a therapeutic effect on patients lacking SRD5A2, which may partially account for the resistance to finasteride observed in certain BPE patients.
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