Estradiol Ameliorates Acute Kidney Ischemia-Reperfusion Injury by Inhibiting the TGF-βRI-SMAD Pathway

Neutrophil extracellular traps-related genes contribute to sepsis-associated acute kidney injury

BACKGROUND

Neutrophil extracellular traps (NETs) and oxidative stress (OS) may be involved in sepsis-associated acute kidney injury (SA-AKI). The aim of this study was to identify potential regulators which modulate NETs and OS in SA-AKI, and to find potential therapeutic agents.

METHODS AND MATERIALS

SA-AKI-related datasets GSE255281 and GSE225192 were downloaded from Gene Expression Omnibus. Molecular subtypes associated with NETs were identified by unsupervised clustering. The OS-related genes were obtained by weighted gene co-expression network analysis. Differentially expressed genes were screened by "limma" package in R. Least absolute shrinkage and selection operator algorithm was applied to identify the hub genes. Additionally, the biological functions of the hub genes were analyzed with single sample gene set enrichment analysis. NetworkAnalyst database was searched to screen the drugs targeting the hub targets. qRT-PCR was used to analyze the expression of key genes in the peripheral blood mononuclear cells (PBMCs) of the patients with SA-AKI and healthy controls. HK-2 cells and human umbilical vein endothelial cells (HUVECs) were induced by lipopolysaccharide (LPS) to construct a SA-AKI model, and the effects of estradiol and (+)-JQ1 on HK-2 cells and HUVECs were evaluated by CCK-8 assays, flow cytometry and OS indices.

RESULTS

Based on NETs-related genes, SA-AKI samples could be divide into two subgroups, and the differentially expressed genes between two subgroups were associated with OS. In silico analyses identified 13 hub targets. The expression of ECT2 and CHRDL1 in PBMCs of SA-AKI patients was significantly lower than that in control group, and the expressions of PTAFR, CSF3 and FOS were significantly higher. Estradiol and (+)-JQ1, which targeted more of the hub targets with good binding affinity, could increase the viability of HK-2 cells and HUVECs induced by LPS and inhibit apoptosis and OS.

CONCLUSION

Formation of NETs, contributes to OS and pathogenesis of SA-AKI. Estradiol and (+)-JQ1, targeting multiple regulators in the formation of NETs, may be potential therapeutic agents for the treatment of SA-AKI.

CLINICAL TRIAL NUMBER

Not applicable.

Mechanistic insights into the anti-fibrotic effects of estrogen via the PI3K-Akt pathway in frozen shoulder

The development of frozen shoulder (FS) is primarily characterized by pathological fibrosis, yet clinical treatment options remain limited. Recent studies have identified estrogen depletion during perimenopause as a significant contributor to the onset of FS and fibrosis. This study investigates the role of estradiol (E2) and the estrogen-related receptor (GPER) in fibrotic processes associated with FS to elucidate the underlying mechanisms. The functional relationship between E2, GPER, and FS progression was examined using a rat immobilization model and synovial-derived fibroblasts (SFs) from FS patients. E2's effects on GPER expression, fibroblast activation, and tissue fibrosis were evaluated through Western blotting, immunofluorescence staining, collagen contraction assays, wound healing assays, and histological staining. RNA sequencing identified signaling pathways and key regulators involved in E2 treatment. Both E2 and the GPER activator G1 exhibited antifibrotic effects, improving shoulder mobility, reducing extracellular matrix (ECM) deposition in the periarticular capsule, and decreasing the expression of fibrosis-related genes, including fibronectin, α-SMA, and COL3. In contrast, the GPER inhibitor G15 reversed these effects, suggesting that E2 mediates its antifibrotic action through GPER activation. Mechanistically, KEGG pathway analysis revealed that E2 suppresses the PI3K/AKT signaling pathway by inhibiting PI3K and AKT phosphorylation, thereby preventing fibroblast activation and reversing FS-associated fibrosis. These findings provide mechanistic insights into the previously unrecognized role of GPER in FS progression and may open new avenues for research to optimize future clinical therapies.

Identification of c-Jun phosphorylation as a crucial mediator of complement activation in renal ischemia-reperfusion injury revealed by phosphoproteomics and functional validation

BACKGROUND

Ischemia reperfusion injury (IRI) is an unavoidable condition that primarily affects graft function in renal transplantation. Blockage of complement activation by complement receptor immunoglobulin/ factor H (CRIg/FH), a novel complement inhibitor, shows great potency to ameliorate renal IRI. Sublytic membrane attack complex (MAC) disrupts cellular functions via the activation of different protein kinases and phosphorylation of critical signal transduction factors. We aimed to investigate whether complement activation triggered shift in phosphorylation status in IRI.

METHODS AND RESULTS

We performed a LC-MS/MS-based quantitative phosphoproteomic analysis of CRIg/FH-IRI, PBS-IRI and Sham mice, depicting a thorough protein phosphorylation profile. C3d and MAC staining were conducted to study the complement activation status. In vitro model mimicking complement mediated IRI tubular injury was achieved by applying normal human serum (NHS) to TCMK cells. By hierarchical clustering, we observed that CRIg/FH treatment reversed the hyperphosphorylation status triggered by IRI. Differentially expressed phosphoproteins (DEPs) were associated with focal adhesion, integrin activation, actin cytoskeleton organization and cell junction. We identified c-Jun as the most differentially phosphorylated transcriptional factor regulated by complement activation, the S63 phosphorylation of which was verified both in vitro and in vivo and screened for its downstream targets. JNK inhibitor reduced the phosphorylation of c-Jun and attenuated accumulation of the C3d on the tubular epithelial cells.

CONCLUSION

We proposed a crucial role of c-Jun phosphorylation in complement activation induced by renal IRI by combining phosphoproteomic approaches and protein validation, which hopefully could provide novel insights into the pathological mechanisms of IRI.

Sex Differences in Outcomes of Chimeric Antigen Receptor (CAR) T-Cell Therapy

BACKGROUND

Chimeric Antigen Receptor (CAR) T-cell therapy has arisen as a revolutionary treatment for hematologic malignancies. Our study aimed to evaluate how sex differences affect outcomes and complications following CAR T-cell therapy.

METHODS

Utilizing the Nationwide Readmissions Database (2018-2020), we identified patients and divided them into male and female groups. Hospital outcomes and complications were compared among these two groups after propensity score matching to match groups based on comorbidities, producing two comparable cohorts.

RESULTS

We analyzed 2928 patients (1832 males, 62.6%, mean age 60.3 ± 13.7 years; 1096 females, 37.4%, mean age 59.1 ± 13.8 years). After propensity score matching (1:1ratio), 1092 males and females were compared. There were no significant sex differences in early mortality (adjusted odd ratios (aOR): 1.04 [95% CI 0.69-1.57]), 30-day readmissions (aOR: 1.05 [95% CI 0.86-1.30]), or nonhome discharge (aOR: 0.89 [95% CI 0.60-1.31]). Females had higher odds of leukopenia (aOR: 1.26 [95% CI 1.06-1.50]) but lower odds of acute kidney injury (aOR: 0.68 [95% CI 0.52-0.88]).

CONCLUSIONS

No sex differences were found in hospital outcomes, including early mortality, 30-day readmission, and nonhome discharge after CAR T-cell therapy.

Gender Differences in Adenine Diet-Induced Kidney Toxicity: The Impact of 17β-Estradiol on Renal Inflammation and Fibrosis

Chronic kidney disease (CKD) involves ongoing impairment of kidney function and structural changes. Previous studies indicated that males have a substantially higher prevalence of CKD than those observed in females. Here, we compared the gender differences in CKD development by comparing age-matched male and female mice subjected to a 0.25% adenine diet (AD) for two weeks. Male mice showed a significantly greater decrease in kidney function than female mice, as evidenced by the elevated blood urea nitrogen levels (M-AD: 160 ± 5 mg/dL, F-AD: 90 ± 4 mg/dL; p < 0.001). Furthermore, male mice kidneys exhibited pronounced tubule dilation and kidney damage, as detected by histological and biochemical methods. The extent of fibrosis was quantified using multiple biological methods, revealing a greater degree of fibrosis in male kidneys. We next indicated the inflammatory responses in the kidneys. Similar to the extent of fibrosis, AD-fed male mice showed significantly increased levels of pro-inflammatory markers, including cytokine expression and infiltration of immune cell, compared to female mice. Based on in vivo observations, the anti-inflammatory and anti-fibrotic effects of 17β-estradiol (E2) were further evaluated in vitro conditions. E2 pre-treatment significantly reduced lipopolysaccharide-induced inflammatory response through inhibition of the nuclear factor-kappa B (NF-κB) pathway in NRK52E renal epithelial cells. In NRK49F renal fibroblasts, E2 pre-treatment also reduced TGFβ-induced fibrotic responses. We further demonstrated that E2 markedly decreased fibrosis and inflammation in AD-fed mouse kidneys. Our observations revealed that male mice kidneys exhibited a heightened inflammatory and fibrotic response compared to female mice kidneys. Additionally, our findings suggest that the observed sex differences may be partially attributed to the potential anti-inflammatory and anti-fibrotic effects of E2.

Narciclasine attenuates sepsis-associated acute kidney injury through the ESR1/S100A11 axis

Narciclasine (Ncs) was effective in sepsis management due to its antioxidant properties. The present study dissected the protective effects of Ncs against sepsis-associated acute kidney injury (SA-AKI) and the molecular mechanisms. The SA-AKI mice were developed using cecum ligation and puncture and pretreated with Ncs and adenoviruses. Human renal microvascular endothelial cells (RMECs) were induced with LPS and treated with Ncs. Ncs alleviated proximal tubular dilatation, interstitial widening, and necrosis in renal tissues and reduced the renal injury marker and pro-inflammatory cytokine levels in the serum of SA-AKI mice. Ncs promoted the expression of ZO-1, VE-cadherin, and CD31 and the activities of SOD, GSH-Px, and CAT, and inhibited the levels of pro-inflammatory cytokines, and apoptosis rate in LPS-treated RMECs. Estrogen receptor 1 (ESR1) was a target protein of Ncs, and S100 calcium-binding protein A11 (S100A11) was a target of the transcription factor ESR1. Ncs blocked transcription of S100A11 by inhibiting ESR1. Silencing of S100A11 overturned the deteriorating effects of ESR1 overexpression on SA-AKI progression in vivo and RMEC injury in vitro. These findings suggest that Ncs may ameliorate SA-AKI by repressing the ESR1/S100A11 signaling, providing a novel perspective for research on SA-AKI.

Potential nuances in renoprotective properties of estrogen in females

A current study by Kitai et al. found that ovariectomy before estrogen/female sex hormone sensitization at puberty provided protection against kidney ischemia reperfusion injury, challenging the general consensus within the field that estrogen provides renoprotective function. These results are intriguing and could have important clinical implications, while requiring some clarification and substantiation of the conclusions reported.

An update on the role of sex hormones in the function of the cardiorenal mitochondria

Multiple studies have highlighted the crucial role of mitochondrial bioenergetics in understanding the progression of cardiorenal diseases, revealing new potential treatment targets related to mitochondrial metabolism. There are well-established sexual dimorphisms in cardiac and renal physiology, with premenopausal females being generally protected from pathology compared with males. The mechanisms of this protection remain to be fully elucidated, however, they clearly depend, at least in part, on sex hormones. Sex hormones contribute to regulating mitochondrial function, and vice versa, highlighting the existence of a bidirectional relationship pivotal for cellular energy metabolism; however, there are still large gaps in knowledge when the sex differences in mitochondrial bioenergetics in health and disease are concerned. This manuscript provides an overview of the new evidence that has been accumulated regarding the role of sex hormones in renal and cardiac mitochondria-dependent cellular energetics, metabolism, and signaling, mainly focusing on the data obtained within the last 3-5 years. We briefly discuss mitochondrial function and different types of sex hormones for the reader and then focus on novel research underscoring the emerging mitochondrial pathways regulated by sex hormones, which might be of interest for the development of novel therapeutic strategies for cardiorenal conditions.

Cardiac surgery-associated acute kidney injury in cardiopulmonary bypass: a focus on sex differences and preventive strategies

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a high-risk complication with well-recognized increased morbidity and mortality after cardiac surgery attributable in large part to cardiopulmonary bypass (CPB)-associated factors contributing to AKI including hemodilution, hypothermia, hypotension, and exposure to artificial surfaces. These conditions disrupt the renal microcirculation and activate local and systemic inflammatory responses to nonpulsatile flow and low perfusion pressure. The underlying mechanisms of CSA-AKI in CPB are not fully understood, and the incidence of CSA-AKI remains high at around 30%. Furthermore, women appear to be more vulnerable than men to the renal injury associated with CPB even though the overall incidence of cardiovascular and kidney diseases is lower in premenopausal women. Nevertheless, estrogen elicits renoprotective effects in several ways including mitigating inflammation, promoting natriuresis, and endothelial protection as shown in preclinical studies. However, women have higher rates of CSA-AKI and these are exacerbated in postmenopausal women. This leads to the conundrum of whether sex, age, and hormonal status differences influence CSA-AKI. In this review, we briefly discuss the pathophysiology of CSA-AKI in CPB and sex differences in kidney functions with a focus on the possible role of estrogen-specific effects in CPB and also possible differences in CPB in women including greater hemodilution. Furthermore, we review strategies to prevent CSA-AKI in CPB with a highlight for potential sex-specific strategies. Improving our understanding of the impact of sex and sex hormones on CSA-AKI initiation and development will allow us to better manage the CPB strategies delivered to all patients.

Chronic mistimed feeding results in renal fibrosis and disrupted circadian blood pressure rhythms

Circadian disruption is a disturbance in biological timing, which can occur within or between different organizational levels, ranging from molecular rhythms within specific cells to the misalignment of behavioral and environmental cycles. Previous work from our group showed that less than 1 wk of food restriction to the light (inactive) period is sufficient to invert diurnal blood pressure rhythms in mice. However, kidney excretory rhythms and functions remained aligned with the light-dark cycle. Shift workers have an increased risk of cardiovascular disease that may different between sexes and often have irregular mealtimes, making the possibility of mistimed feeding as a potential contributor to the development of kidney disease. Thus, we hypothesized that chronic mistimed food intake would result in adverse cardiorenal effects, with sex differences in severity. Here, we show that chronic circadian disruption via mistimed feeding results in renal fibrosis and aortic stiffness in a sex-dependent manner. Our results indicate the importance of meal timing for the maintenance of blood pressure rhythms and kidney function, particularly in males. Our results also demonstrate that females are better able to acclimate to circadian-related behavioral change. NEW & NOTEWORTHY Circadian disruption through mistimed feeding resulted in nondipping blood pressure, renal fibrosis, and arterial stiffness that were less severe in females versus males. Mice fed exclusively during the daytime maintain their circadian rhythms of locomotor activity regardless of their loss of blood pressure rhythms. Although these mice ate less food, they maintained body weight, suggesting inefficiencies in overall metabolism. These findings demonstrate the importance of maintaining optimal food intake patterns to prevent cardiorenal pathophysiology.

Identification of TACSTD2 as novel therapeutic targets for cisplatin-induced acute kidney injury by multi-omics data integration

Cisplatin-induced acute kidney injury (CP-AKI) is a common complication in cancer patients. Although ferroptosis is believed to contribute to the progression of CP-AKI, its mechanisms remain incompletely understood. In this study, after initially processed individual omics datasets, we integrated multi-omics data to construct a ferroptosis network in the kidney, resulting in the identification of the key driver TACSTD2. In vitro and in vivo results showed that TACSTD2 was notably upregulated in cisplatin-treated kidneys and BUMPT cells. Overexpression of TACSTD2 accelerated ferroptosis, while its gene disruption decelerated ferroptosis, likely mediated by its potential downstream targets HMGB1, IRF6, and LCN2. Drug prediction and molecular docking were further used to propose that drugs targeting TACSTD2 may have therapeutic potential in CP-AKI, such as parthenolide, progesterone, premarin, estradiol and rosiglitazone. Our findings suggest a significant association between ferroptosis and the development of CP-AKI, with TACSTD2 playing a crucial role in modulating ferroptosis, which provides novel perspectives on the pathogenesis and treatment of CP-AKI.

Sex-related differences in SIRT3-mediated mitochondrial dynamics in renal ischemia/reperfusion injury

The prevalence of renal ischemia/reperfusion injury (IRI) in premenopausal women is considerably lower than that in age-matched men. This suggests that sex-related differences in mitochondrial function and homeostasis may contribute to sexual dimorphism in renal injury, though the mechanism remains unclear. Mouse model of unilateral left renal IRI with contralateral kidney enucleation, Ovariectomy in female mice, and a human embryonic kidney (HEK) cell model of hypoxia-reoxygenation were used to study how estrogen affects the sexual dimorphism of renal IRI through SIRT3 in vitro and in vivo, respectively. Here, we demonstrate differential expression of renal SIRT3 may induce sexual dimorphism in IRI using the renal IRI model. Higher SIRT3 level in female mice was associated with E2-induced protection of renal tubular epithelium, reduced mitochondrial reactive oxygen species (ROS), and IRI resistance. In hypoxia-reoxygenated HEK cells, SIRT3 knockdown increased oxidative stress, shifted the interconnected mitochondrial network toward fission, exacerbated hypoxia/reoxygenation-induced endoplasmic reticulum stress (ERS), and abolished the protective effects of E2 on IRI. Mechanistically, the SIRT3 level is E2-dependent and that E2 increases the SIRT3 protein level via estrogen receptor. SIRT3 targeted an i-AAA protease, yeast mitochondrial AAA metalloprotease (YME1L1), and hydrolyzed long optic atrophy 1 (L-OPA) to short-OPA1 (S-OPA1) by deacetylating YME1L1, regulating mitochondrial dynamics toward fusion to reduce oxidative stress and ERS. These findings explored the mechanism by how estrogen alleviates renal IRI and providing a basis for potential therapeutic interventions targeting SIRT3.

Sex differences in the association of long-term exposure to heat stress on kidney function in a large Taiwanese population study

The incidence and prevalence of dialysis in Taiwan are high compared to other regions. Consequently, mitigating chronic kidney disease (CKD) and the worsening of kidney function have emerged as critical healthcare priorities in Taiwan. Heat stress is known to be a significant risk factor for CKD and kidney function impairment. However, differences in the impact of heat stress between males and females remains unexplored. We conducted this retrospective cross-sectional analysis using data from the Taiwan Biobank (TWB), incorporating records of the wet bulb globe temperature (WBGT) during midday (11 AM-2 PM) and working hours (8 AM-5 PM) periods based on the participants' residential address. Average 1-, 3-, and 5-year WBGT values prior to the survey year were calculated and analyzed using a geospatial artificial intelligence-based ensemble mixed spatial model, covering the period from 2010 to 2020. A total of 114,483 participants from the TWB were included in this study, of whom 35.9% were male and 1053 had impaired kidney function (defined as estimated glomerular filtration rate < 60 ml/min/1.73 m2). Multivariable analysis revealed that in the male participants, during the midday period, the 1-, 3-, and 5-year average WBGT values per 1 ℃ increase were significantly positively associated with eGFR < 60 ml/min/1.73 m2 (odds ratio [OR], 1.096, 95% confidence interval [CI] = 1.002-1.199, p = 0.044 for 1 year; OR, 1.093, 95% CI = 1.000-1.196, p = 0.005 for 3 years; OR, 1.094, 95% CI = 1.002-1.195, p = 0.045 for 5 years). However, significant associations were not found for the working hours period. In the female participants, during the midday period, the 1-, 3-, and 5-year average WBGT values per 1 ℃ increase were significantly negatively associated with eGFR < 60 ml/min/1.73 m2 (OR, 0.872, 95% CI = 0.778-0.976, p = 0.018 for 1 year; OR, 0.874, 95% CI = 0.780-0.978, p = 0.019 for 3 years; OR, 0.875, 95% CI = 0.784-0.977, p = 0.018 for 5 years). In addition, during the working hours period, the 1-, 3-, and 5-year average WBGT values per 1 ℃ increase were also significantly negatively associated with eGFR < 60 ml/min/1.73 m2 (OR, 0.856, 95% CI = 0.774-0.946, p = 0.002 for 1 year; OR, 0.856, 95% CI = 0.774-0.948, p = 0.003 for 3 years; OR, 0.853, 95% CI = 0.772-0.943, p = 0.002 for 5 years). In conclusion, our results revealed that increased WBGT was associated with impaired kidney function in males, whereas increased WBGT was associated with a protective effect against impaired kidney function in females. Further studies are needed to elucidate the exact mechanisms underlying these sex-specific differences.

Interaction of estradiol and renin-angiotensin system with microRNAs-21 and -29 in renal fibrosis: focus on TGF-β/smad signaling pathway

Kidney fibrosis is one of the complications of chronic kidney disease (CKD (and contributes to end-stage renal disease which requires dialysis and kidney transplantation. Several signaling pathways such as renin-angiotensin system (RAS), microRNAs (miRNAs) and transforming growth factor-β1 (TGF-β1)/Smad have a prominent role in pathophysiology and progression of renal fibrosis. Activation of classical RAS, the elevation of angiotensin II (Ang II) production and overexpression of AT1R, develop renal fibrosis via TGF-β/Smad pathway. While the non-classical RAS arm, Ang 1-7/AT2R, MasR reveals an anti-fibrotic effect via antagonizing Ang II. This review focused on studies illustrating the interaction of RAS with sexual female hormone estradiol and miRNAs in the progression of renal fibrosis with more emphasis on the TGF-β signaling pathway. MiRNAs, especially miRNA-21 and miRNA-29 showed regulatory effects in renal fibrosis. Also, 17β-estradiol (E2) is a renoprotective hormone that improved renal fibrosis. Beneficial effects of ACE inhibitors and ARBs are reported in the prevention of renal fibrosis in patients. Future studies are also merited to delineate the new therapy strategies such as miRNAs targeting, combination therapy of E2 or HRT, ACEis, and ARBs with miRNAs mimics and antagomirs in CKD to provide a new therapeutic approach for kidney patients.

Effects and mechanisms of frehmaglutin D and rehmaionoside C improve LPS-induced acute kidney injury through the estrogen receptor-mediated TLR4 pathway in vivo and in vitro

BACKGROUND

Sepsis-induced acute kidney injury (S-AKI) is an inflammatory disease with sex differences and there has no effective drugs to cure it. Frehmaglutin D (Fre D) and rehmaionoside C (Reh C) are two violetone compounds with estrogenic activity isolated from Rehmannia glutinosa. However, whether these two drugs exert protective effects on S-AKI through their estrogen-like activity are unclear.

PURPOSE

This study aimed to explore the effects and mechanisms of Fre D and Reh C on lipopolysaccharide (LPS)-induced S-AKI through the estrogen receptor pathway in vivo and in vitro and to explore the interaction between ER and TLR4 for the first time.

METHODS

The LPS-induced female BALB/c mice S-AKI mouse model was established by adding the estrogen receptor antagonist ICI182,780. Renal function, inflammation, oxidative stress, apoptosis, immune cells, and expression of key proteins of the ER-TLR4-IL-1β pathway were tested. The affinity of Fre D and Reh C for the ER was investigated by molecular docking. Then, an in vitro S-AKI model was established, and ERα/ERβ antagonists (MPP/PHTPP) were added and combined with gene overexpression techniques. The interaction between ER and TLR4 was further explored by Co-IP, GST pull-down and SPR techniques.

RESULTS

Fre D and Reh C ameliorated LPS-induced renal damage, inflammation in mice, regulated the immune cells, decreased ROS levels, increased ERα and ERβ protein expression, and decreased TLR4, caspase 11 and IL-1β protein expression. These effects were blocked by ICI182,780. Molecular docking results showed that Fre D and Reh C bound ERα and ERβ with similar potency. The results of in vitro suggested that Fre D and Reh C reduced the levels of inflammation, ROS and apoptosis, TLR4, caspase 11, and IL-1β protein expression and increased ERα/ERβ protein expression in cells. All of these effects were reversed by the addition of MPP/PHTPP and further enhanced after ERα/ERβ gene overexpression with no significant difference in effects. Moreover, there was an indirect or direct interaction between ER and TLR4, and the binding of ERα and ERβ to TLR4 was concentration dependent.

CONCLUSION

Fre D and Reh C may improve S-AKI through the ER-TLR4-IL-1β pathway and may act on both ERα and ERβ receptors. Moreover, ERα and ERβ may interact directly or indirectly with TLR4, which was studied for the first time.

Activation of GPER1 in macrophages ameliorates UUO-induced renal fibrosis

Numerous studies have proven the critical role of macrophages in the renal fibrosis process. Notably, G Protein-coupled Estrogen Receptor 1 (GPER1), a novel estrogen receptor, has been shown to play a ubiquitous role in regulating macrophage activities and proinflammatory pathways. However, the precise role of GPER1 in macrophage-mediated renal fibrosis is unknown. In this study, we aimed to investigate the function of macrophage GPER1 in the UUO-induced renal fibrosis model. Compared to vehicle-treated ovariectomized (OVX) female and male unilateral ureteral obstruction (UUO) models, we observed that G-1 (GPER1 agonist)-treated OVX female and male UUO mice had fewer renal fibrotic lesions and less M1 and M2 macrophage infiltration in the kidney tissues. Conversely, Gper1 deletion in male UUO mice accelerated renal fibrosis and increased inflammation. In vitro studies also revealed that GPER1 activation reduced M0 macrophage polarization towards M1 or M2 phenotypes. The RNA-sequencing analysis and immunoblotting indicated that GPER1 activation was primarily involved in downregulating immune pathways activation and inactivating MAPK pathways. Tubular epithelial cells co-cultured with G-1-pretreated M1 macrophages exhibited fewer injuries and immune activation. In addition, fibroblasts co-cultured with G-1-pretreated M2 macrophages showed downregulated extracellular matrix expression. Overall, this is the first study to demonstrate the effect of GPER1 on macrophage-mediated renal fibrosis via inhibition of M1 and M2 macrophage activation. These findings indicate that GPER1 may be a promising therapeutic target for treating renal fibrosis.

Prunetin in a GPR30-dependent manner mitigates renal ischemia/reperfusion injury in rats via interrupting indoxyl sulfate/TLR4/TRIF, RIPK1/RIPK3/MLKL, and RIPK3/PGAM5/DRP-1 crosstalk

The potential health benefits of phytochemicals in preventing and treating diseases have gained increasing attention. Here, we proved that the methylated isoflavone prunetin possesses a reno-therapeutic effect against renal ischemia/reperfusion (I/R) insult by activating G protein-coupled receptor 30 (GPR30). After choosing the therapeutic dose of prunetin against renal I/R injury in the pilot study, male Sprague Dawley rats were allocated into 5 groups; viz., sham-operated (SO), SO injected with 1 mg/kg prunetin intraperitoneally for three successive days, untreated I/R, I/R treated with prunetin, and I/R treated with G-15, the selective GPR30 blocker, followed by prunetin. Treatment with prunetin reversed the I/R renal injury effect and majorly restored normal renal function and architecture. Mechanistically, prunetin restored the I/R-induced depletion of renal GPR30, an impact that was canceled by the pre-administration of G-15. Additionally, post-administration of prunetin normalized the boosted inflammatory markers indoxyl sulfate, TLR4, and TRIF and abrogated renal cell demise by suppressing necroptotic signaling, verified by the inactivation of p-RIPK1, p-RIPK3, and p-MLKL while normalizing the inhibited caspase-8. Besides, prunetin reversed the I/R-mediated mitochondrial fission by inhibiting the protein expression of PGMA5 and p-DRP-1. All these favorable impacts of prunetin were nullified by G-15. To sum up, prunetin exhibited a significant reno-therapeutic effect evidenced by the enhancement of renal morphology and function, the suppression of the inflammatory cascade indoxyl sulfate/TLR4/TRIF, which turns off the activated/phosphorylated necroptotic trajectory RIPK1/RIPK3/MLKL, while enhancing caspase-8. Additionally, prunetin opposed the mitochondrial fission pathway RIPK3/PGMA5/DRP-1, effects that are mediated via the activation of GPR30.

Estradiol protects female mice from hyperuricemia induced by PCB138 exposure

Polychlorinated biphenyls (PCBs) are a type of persistent organic pollutant (POP). Our previous study demonstrated that exposure to 0.5-50 μg/kg bw PCB138 during postnatal days (PND) 3-21 led to elevated serum uric acid (UA) levels and kidney injury in adult male mice. Given that the prevalence of hyperuricemia (HUA) is significantly lower in women than in men, it is worth investigating whether POP-induced HUA and its secondary kidney injury have sexual dimorphism. Herein, we exposed female mice to 0.5-50 μg/kg bw PCB138 during PND 3-21, resulting in elevated serum UA levels, but without causing significant kidney damage. Concurrently, we found a negative correlation between serum 17β-estradiol (E2) and serum UA levels. We also observed down-regulation of estrogen receptor (ER) protein levels in the kidneys of the PCB138-exposed groups. Furthermore, our study showed that E2 rescued the increased UA level and cytotoxicity caused by HUA in human renal tubular epithelial (HK-2) cells. Collectively, our findings suggest that E2 likely plays a crucial protective role in PCB138-induced HUA and kidney injury in female mice. Our research highlights the existence of sexual dimorphism in kidney injury secondary to HUA induced by POPs, which could provide guidance for individuals of different genders in preventing kidney injury caused by environmental factors.

Gender and Renal Insufficiency: Opportunities for Their Therapeutic Management?

Acute kidney injury (AKI) is a major clinical problem associated with increased morbidity and mortality. Despite intensive research, the clinical outcome remains poor, and apart from supportive therapy, no other specific therapy exists. Furthermore, acute kidney injury increases the risk of developing chronic kidney disease (CKD) and end-stage renal disease. Acute tubular injury accounts for the most common intrinsic cause of AKI. The main site of injury is the proximal tubule due to its high workload and energy demand. Upon injury, an intratubular subpopulation of proximal epithelial cells proliferates and restores the tubular integrity. Nevertheless, despite its strong regenerative capacity, the kidney does not always achieve its former integrity and function and incomplete recovery leads to persistent and progressive CKD. Clinical and experimental data demonstrate sexual differences in renal anatomy, physiology, and susceptibility to renal diseases including but not limited to ischemia-reperfusion injury. Some data suggest the protective role of female sex hormones, whereas others highlight the detrimental effect of male hormones in renal ischemia-reperfusion injury. Although the important role of sex hormones is evident, the exact underlying mechanisms remain to be elucidated. This review focuses on collecting the current knowledge about sexual dimorphism in renal injury and opportunities for therapeutic manipulation, with a focus on resident renal progenitor stem cells as potential novel therapeutic strategies.

Evaluation of pharmacokinetics and safety of a long-term estradiol-releasing stent in rat uterine

Purpose

Intrauterine adhesion (IUA), often leading to gynecological complications including amenorrhea, abdominal pain and infertility, is frequently induced by injuries to the endometrium. Hence it would be of great benefit to take efforts to prevent adhesion after intrauterine operations. Orally administration of 17β-estradiol (E2) is commonly used to promote endometrium regeneration, but is limited by low concentrations at the injured sites. We aim at preparing an E2-releasing uterine stent, which could improve the efficiency of E2 therapy and be utilized for IUA prevention.

Methods

We designed a silicone rubber stent, which could be implanted in the uterine cavity and continuously release E2 in long term. Stents were placed in rodent uterine, and removed at different time points. Remaining E2 in stent was measured by high performance liquid chromatography (HPLC), and organ E2 concentrations were detected by enzyme-linked immuno sorbent assay (ELISA). Endometrium morphology was examined by histological staining of paraffin sections.

Results

Our stent showed a controlled release of E2 in rodent uterine for over 60 days, and significantly increased E2 concentration in serum and in situ uterine. After the stent was removed from uterine, E2 rapidly reverted to a normal level. Also, the stent did not induce pathological changes in endometrium.

Conclusions

The uterine stent provided abundant local E2 in uterine cavity with satisfactory safety. The silicone rubber based E2-releasing uterine stent could be further advanced by adjusting its shape and E2 load for its clinical application, and might promisingly help lowering the incidence of IUA.

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The silicone rubber uterine stent continuously released E2 in long term.

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The E2-releasing uterine stent revealed more efficient E2 delivery capacity than orally administrated E2.

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The E2-releasing uterine stent is safe for endometrium and remote organs.

Covid-19 and adolescent acute kidney injury: Renal recovery with combined enalapril and estrogen therapy

Covid-19 in adolescence with multisystem inflammatory injury (MIS-C) is a newly described condition sharing key features with Kawasaki disease and toxic shock syndrome. A May 2020 United Nations WHO brief covering findings from North America and Europe drew notice to this acute post-viral illness characterized by severe, diffuse hyperinflammation leading to multiorgan failure. While females diagnosed with Covid-19 generally have more favorable outcomes than males, this protection is negated by a low estrogen state. This case reports on acute kidney injury/MIS-C with amenorrhea from ovarian insufficiency in childhood, itself an uncommon presentation of idiopathic hypogonadism. Three exon variants were previously identified in a healthy, phenotypically normal 46,XX adolescent who subsequently underwent whole genome sequencing (WGS). She had only two spontaneous menses with a provisional diagnosis of premature ovarian insufficiency made by age 15. Against this background, Covid-19 infection necessitated hospital admission where progressively reduced renal function was a prime component of MIS-C. Combined angiotensin-converting enzyme inhibitor plus transdermal estrogen replacement therapy resulted in normalized estimated glomerular filtration rate (eGFR) from baseline 43 to 68 ml/min/1.73 m2, post-treatment. Serum cystatin-C also improved during this interval from 1.69 to 1.19 mg/L. Among 7 Covid-19 high risk intron variants identified was rs3131294 (6p21), near NOTCH4. Another finding at rs8068318 (17q23) was associated with creatine level and eGFR. This is the first work to explore Covid-19 and associated kidney injury as a component of MIS-C at the intersection of rare multigene variants and functional ovarian loss. The context of transition from adolescence to adulthood is also considered, where successful recovery of renal function was achieved with combined enalapril and supplemental estrogen.