Recryopreservation (recryo) is occasionally applied in clinical, while the underlying mechanism of impaired clinical outcomes after recryo remains unclear. In this study, frozen embryo transfer (FET) cycles of single blastocyst transfer in an academic reproductive medicine center were enrolled. According to the number of times blastocysts experienced cryopreservation, they were divided into the cryopreservation (Cryo) group and the Recryo group. Donated human blastocysts were collected and detected for mechanism exploration. It was found that recryo procedure resulted in impaired blastocyst developmental potential, including decreased implantation rate, reduced biochemical pregnancy rate, declined clinical pregnancy rate, higher early miscarriage rate, and lower live birth rate. Moreover, recryo led to impaired trophectoderm (TE) function, exhibiting lower human chorionic gonadotropin levels 12 days after FET. In addition, single-cell RNA sequencing showed that the expression of genes involved in cell adhesion and embryo development were altered. More specifically, activated endoplasmic reticulum (ER) pathway and induced apoptosis were further verified by immunofluorescence and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay involving in the recryo procedure. In conclusion, recryo could interfere with the process of blastocyst implantation by impairing TE function, affecting blastocyst adhesion, activating ER stress pathway and inducing apoptosis. It provides caution to embryologists about the potential risk of recryopreservation.

Introduction: Vascular calcification is accelerated in patients with chronic kidney disease (CKD) and increases the risk of cardiovascular events. CKD is frequently associated with anemia. Daprodustat (DPD) is a prolyl hydroxylase inhibitor for the treatment of CKD-associated anemia that enhances erythropoiesis through the activation of the hypoxia-inducible factor 1 (HIF-1) pathway. Studies showed that DPD promotes osteogenic differentiation of human aortic smooth muscle cells (HAoSMCs) and increases aorta calcification in mice with CKD. HIF-1 activation has been linked with endoplasmic reticulum (ER) stress; therefore, here we investigated the potential contribution of ER stress, particularly activating transcription factor 4 (ATF4), to the pro-calcification effect of DPD. Methods: Here, we used an adenine-induced CKD mouse model and HAoSMCs as an in vitro vascular calcification model to study the effect of DPD. Results: DPD treatment (15 mg/kg/day) corrects anemia but increases the expression of hypoxia (Glut1, VEGFA), ER stress (ATF4, CHOP, and GRP78), and osteo-/chondrogenic (Runx2, Sox9, BMP2, and Msx2) markers and accelerates aorta and kidney calcification in CKD mice. DPD activates the PERK/eIF2α/ATF4/CHOP pathway and promotes high phosphate-induced osteo-/chondrogenic differentiation of HAoSMCs. Inhibition of ER stress with 4-PBA or silencing of ATF4 attenuates HAoSMC calcification. DPD-induced ATF4 expression is abolished in the absence of HIF-1α; however, knockdown of ATF4 does not affect HIF-1α expression. Conclusion: We concluded that DPD induces ER stress in vitro and in vivo, in which ATF4 serves as a downstream effector of HIF-1 activation. Targeting ATF4 could be a potential therapeutic approach to attenuate the pro-calcific effect of DPD.

Cellular senescence represents a condition of irreversible cell cycle arrest, characterized by heightened senescence-associated beta-galactosidase (SA-β-Gal) activity, senescence-associated secretory phenotype (SASP), and activation of the DNA damage response (DDR). Diabetic kidney disease (DKD) is a significant contributor to end-stage renal disease (ESRD) globally, with ongoing unmet needs in terms of current treatments. The role of senescence in the pathogenesis of DKD has attracted substantial attention with evidence of premature senescence in this condition. The process of cellular senescence in DKD appears to be associated with mitochondrial redox pathways, autophagy, and endoplasmic reticulum (ER) stress. Increasing accumulation of senescent cells in the diabetic kidney not only leads to an impaired capacity for repair of renal injury, but also the secretion of pro-inflammatory and profibrotic cytokines and growth factors causing inflammation and fibrosis. Current treatments for diabetes exhibit varying degrees of renoprotection, potentially via mitigation of senescence in the diabetic kidney. Targeting senescent cell clearance through pharmaceutical interventions could emerge as a promising strategy for preventing and treating DKD. In this paper, we review the current understanding of senescence in DKD and summarize the possible therapeutic interventions relevant to senescence in this field.

Oxalate-induced damage to renal tubular epithelial cells (RTECs) is an essential factor in the incident kidney stone, but the specific mechanism is unclear. Recent research has pinpointed interacting areas within the endoplasmic reticulum and mitochondria, called mitochondria-associated membranes (MAMs). These studies have linked endoplasmic reticulum stress (ERS) and oxidative imbalance to kidney disease development. The sigma-1 receptor (S1R), a specific protein found in MAMs, is involved in various physiological processes, but its role in oxalate-induced kidney stone formation remains unclear. In this study, we established cellular and rat models of oxalate-induced kidney stone formation to elucidate the S1R\'s effects against ERS and apoptosis and its mechanism in oxalate-induced RTEC injury. We found that oxalate downregulated S1R expression in RTECs and escalated oxidative stress and ERS, culminating in increased apoptosis. The S1R agonist dimemorfan up-regulated S1R expression and mitigated ERS and oxidative stress, thereby reducing apoptosis. This protective effect was mediated through S1R inhibition of the CHOP pathway. Animal experiments demonstrated that S1R\'s activation attenuated oxalate-induced kidney injury and alleviated kidney stone formation. This is the first study to establish the connection between S1R and kidney stones, suggesting S1R\'s protective role in inhibiting ERS-mediated apoptosis to ameliorate kidney stone formation.

The unfolded protein response (UPR) is a conserved and adaptive intracellular pathway that relieves the endoplasmic reticulum (ER) stress by activating ER transmembrane stress sensors. As a consequence of ER stress, the inhibition of nonsense-mediated mRNA decay (NMD) is due to an increase in the phosphorylation of eIF2α, which has the effect of inhibiting translation. However, the role of NMD in maintaining ER homeostasis remains unclear. In this study, we found that the three NMD factors, up-frameshift (UPF)1, UPF2, or UPF3B, were required to negate the UPR. Among these three NMD factors, only UPF3B interacted with inositol-requiring enzyme-1α (IRE1α). This interaction inhibited the kinase activity of IRE1α, abolished autophosphorylation, and reduced IRE1α clustering for ER stress. BiP and UPF3B jointly control the activation of IRE1α on both sides of the ER membrane. Under stress conditions, the phosphorylation of UPF3B was increased and the phosphorylated sites were identified. Both the UPF3BY160D genetic mutation and phosphorylation at Thr169 of UPF3B abolished its interaction with IRE1α and UPF2, respectively, leading to activation of ER stress and NMD dysfunction. Our study reveals a key physiological role for UPF3B in the reciprocal regulatory relationship between NMD and ER stress.

Sepsis causes systemic inflammatory responses and acute lung injury (ALI). Despite modern treatments, sepsis-related ALI mortality remains high. Aqueous extract of Descuraniae Semen (AEDS) exerts anti-endoplasmic reticulum (ER) stress, antioxidant and anti-inflammatory effects. AEDS alleviates inflammation and oedema in ALI. Sodium-potassium-chloride co-transporter isoform 1 (NKCC1) is essential for regulating alveolar fluid and is important in ALI. The NKCC1 activity is regulated by upstream with-no-lysine kinase-4 (WNK4) and STE20/SPS1-related proline/alanine-rich kinase (SPAK). This study aimed to investigate the effects of AEDS on lipopolysaccharide (LPS)-induced ALI model in A549 cells, considering the regulation of ER stress, WNK4-SPAK-NKCC1 cascades, inflammation and apoptosis. Cell viability was investigated by the CCK-8 assay. The expressions of the proteins were assessed by immunoblotting analysis assays. The levels of pro-inflammatory cytokines were determined by ELISA. The expression of cytoplasmic Ca2+ in A549 cells was determined using Fluo-4 AM. AEDS attenuates LPS-induced inflammation, which is associated with increased pro-inflammatory cytokine expression and activation of the WNK4-SPAK-NKCC1 pathway. AEDS inhibits the WNK4-SPAK-NKCC1 pathway by regulating of Bcl-2, IP3R and intracellular Ca2+. WNK4 expression levels are significantly higher in the WNK4-overexpressed transfected A549 cells and significantly decrease after AEDS treatment. AEDS attenuates LPS-induced inflammation by inhibiting the WNK4-SPAK-NKCC1 cascade. Therefore, AEDS is regarded as a potential therapeutic agent for ALI.

Diabetic neuropathy (DN) is a common complication of diabetes, affecting over 50% of patients, leading to significant pain and a burden. Currently, there are no effective treatments available. Cell death is considered a key factor in promoting the progression of DN. This article reviews how cell death is initiated in DN, emphasizing the critical roles of oxidative stress, mitochondrial dysfunction, inflammation, endoplasmic reticulum stress, and autophagy. Additionally, we thoroughly summarize the mechanisms of cell death that may be involved in the pathogenesis of DN, including apoptosis, autophagy, pyroptosis, and ferroptosis, among others, as well as potential therapeutic targets offered by these death mechanisms. This provides potential pathways for the prevention and treatment of diabetic neuropathy in the future.

In this study, we undertook an extensive investigation to determine how CypB PPIase activity affects preadipocyte differentiation and lipid metabolism. Our findings revealed that inhibition of CypB\'s PPIase activity suppressed the expression of crucial proteins involved in adipocyte differentiation and induced changes in proteins regulating the cell cycle. Furthermore, we clarified the impact of CypB\'s PPIase activity on lipid metabolism via the AKT/mTOR signaling pathway. Additionally, we demonstrated the involvement of CypB\'s PPIase activity in lipid metabolism through the XBP1s pathway. These discoveries offer invaluable insights for devising innovative therapeutic strategies aimed at treating and averting obesity and its related health complications. Targeting CypB\'s PPIase activity may emerge as a promising avenue for addressing obesity-related conditions. Furthermore, our research opens up opportunities for creating new therapeutic strategies by enhancing our comprehension of the processes involved in cellular endoplasmic reticulum stress.

More than two million people worldwide are affected by life-threatening, invasive fungal infections annually. Candida species are the most common cause of nosocomial, invasive fungal infections and are associated with mortality rates above 40%. Despite the increasing incidence of drug-resistance, the development of novel antifungal formulations has been limited. Here we investigate the antifungal mode of action and therapeutic potential of positively charged, synthetic peptide mimics to combat Candida albicans infections. Our data indicates that these synthetic polymers cause endoplasmic reticulum stress and affect protein glycosylation, a mode of action distinct from currently approved antifungal drugs. The most promising polymer composition damaged the mannan layer of the cell wall, with additional membrane-disrupting activity. The synergistic combination of the polymer with caspofungin prevented infection of human epithelial cells in vitro, improved fungal clearance by human macrophages, and significantly increased host survival in a Galleria mellonella model of systemic candidiasis. Additionally, prolonged exposure of C. albicans to the synergistic combination of polymer and caspofungin did not lead to the evolution of tolerant strains in vitro. Together, this work highlights the enormous potential of these synthetic peptide mimics to be used as novel antifungal formulations as well as adjunctive antifungal therapy.

Sex differences may play a role in the etiopathogenesis and severity of metabolic dysfunction-associated steatotic liver disease (MASLD), a disorder characterized by excessive fat accumulation associated with increased inflammation and oxidative stress. We previously observed the development of steatosis specifically in female rats fed a high-fat diet enriched with liquid fructose (HFHFr) for 12 weeks. The aim of this study was to better characterize the observed sex differences by focusing on the antioxidant and cytoprotective pathways related to the KEAP1/NRF2 axis. The KEAP1/NRF2 signaling pathway, autophagy process (LC3B and LAMP2), and endoplasmic reticulum stress response (XBP1) were analyzed in liver homogenates in male and female rats that were fed a 12-week HFHFr diet. In females, the HFHFr diet resulted in the initial activation of the KEAP1/NRF2 pathway, which was not followed by the modulation of downstream molecular targets; this was possibly due to the increase in KEAP1 levels preventing the nuclear translocation of NRF2 despite its cytosolic increase. Interestingly, while in both sexes the HFHFr diet resulted in an increase in the levels of LC3BII/LC3BI, a marker of autophagosome formation, only males showed a significant upregulation of LAMP2 and XBP1s; this did not occur in females, suggesting impaired autophagic flux in this sex. Overall, our results suggest that males are characterized by a greater ability to cope with an HFHFr metabolic stimulus mainly through an autophagic-mediated proteostatic process while in females, this is impaired. This might depend at least in part upon the fine modulation of the cytoprotective and antioxidant KEAP1/NRF2 pathway resulting in sex differences in the occurrence and severity of MASLD. These results should be considered to design effective therapeutics for MASLD.