The Interplay between Glucose-Regulated Protein 78 (GRP78) and Steroids in the Reproductive System

A narrative review on inflammaging and late-onset hypogonadism

The increasing life expectancy observed in recent years has resulted in a higher prevalence of late-onset hypogonadism (LOH) in older men. LOH is characterized by the decline in testosterone levels and can have significant impacts on physical and mental health. While the underlying causes of LOH are not fully understood, there is a growing interest in exploring the role of inflammaging in its development. Inflammaging is a concept that describes the chronic, low-grade, systemic inflammation that occurs as a result of aging. This inflammatory state has been implicated in the development of various age-related diseases. Several cellular and molecular mechanisms have been identified as contributors to inflammaging, including immune senescence, cellular senescence, autophagy defects, and mitochondrial dysfunction. Despite the extensive research on inflammaging, its relationship with LOH has not yet been thoroughly reviewed in the literature. To address this gap, we aim to review the latest findings related to inflammaging and its impact on the development of LOH. Additionally, we will explore interventions that target inflammaging as potential treatments for LOH.

Investigation of the mutated antimicrobial peptides to inhibit ACE2, TMPRSS2 and GRP78 receptors of SARS-CoV-2 and angiotensin II type 1 receptor (AT1R) as well as controlling COVID-19 disease

SARS-CoV-2 is a global problem nowadays. Based on studies, some human receptors are involved in binding to SARS-CoV-2. Thus, the inhibition of these receptors can be effective in the treatment of Covid-19. Because of the proven benefits of antimicrobial peptides (AMPs) and the side effects of chemical drugs, they can be known as an alternative to recent medicines. RCSB PDB to obtain PDB id, StraPep and PhytAMP to acquire Bio-AMPs information and 3-D structure, and AlgPred, Toxinpred, TargetAntiAngio, IL-4pred, IL-6pred, ACPred and Hemopred databases were used to find the best score peptide features. HADDOCK 2.2 was used for molecular docking analysis, and UCSF Chimera software version 1.15, SWISS-MODEL and BIOVIA Discovery Studio Visualizer4.5 were used for mutation and structure modeling. Furthermore, MD simulation results were achieved from GROMACS 4.6.5. Based on the obtained results, the Moricin peptide was found to have the best affinity for ACE2. Moreover, Bacteriocin leucocin-A had the highest affinity for GRP78, Cathelicidin-6 had the best affinity for AT1R, and Bacteriocin PlnK had the best binding affinity for TMPRSS2. Additionally, Bacteriocin glycocin F, Bacteriocin lactococcin-G subunit beta and Cathelicidin-6 peptides were the most common compounds among the four receptors. However, these peptides also have some side effects. Consequently, the mutation eliminated the side effects, and MD simulation results indicated that the mutation proved the result of the docking analysis. The effect of AMPs on ACE2, GRP78, TMPRSS2 and AT1R receptors can be a novel treatment for Covid-19.Communicated by Ramaswamy H. Sarma.

Unveiling the dark side of glucose-regulated protein 78 (GRP78) in cancers and other human pathology: a systematic review

Glucose-Regulated Protein 78 (GRP78) is a chaperone protein that is predominantly expressed in the lumen of the endoplasmic reticulum. GRP78 plays a crucial role in protein folding by assisting in the assembly of misfolded proteins. Under cellular stress conditions, GRP78 can translocate to the cell surface (csGRP78) were it interacts with different ligands to initiate various intracellular pathways. The expression of csGRP78 has been associated with tumor initiation and progression of multiple cancer types. This review provides a comprehensive analysis of the existing evidence on the roles of GRP78 in various types of cancer and other human pathology. Additionally, the review discusses the current understanding of the mechanisms underlying GRP78's involvement in tumorigenesis and cancer advancement. Furthermore, we highlight recent innovative approaches employed in downregulating GRP78 expression in cancers as a potential therapeutic target.

Vulnerability of The Male Reproductive System to SARS-CoV-2 Invasion: Potential Role for The Endoplasmic Reticulum Chaperone Grp78/HSPA5/BiP

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may adversely affect male reproductive tissues and male<br />fertility. This concern is elicited by the higher susceptibility and mortality rate of men to the SARS-CoV-2 mediated coronavirus disease-19 (COVID-19), compared to the women. SARS-CoV-2 enters host cells after binding to a functional receptor named angiotensin-converting enzyme-2 (ACE2) and then replicates in the host cells and gets released into the plasma. SARS-CoVs use the endoplasmic reticulum (ER) as a site for viral protein synthesis and processing, as well as glucose-regulated protein 78 (Grp78) is a key ER chaperone involved in protein folding by preventing newly synthesized proteins from aggregation.<br />Therefore, we analyzed Grp78 expression in various human organs, particularly male reproductive organs, using Broad<br />Institute Cancer Cell Line Encyclopedia (CCLE), the Genotype-Tissue Expression (GTEx), and Human Protein Atlas online<br />datasets. Grp78 is expressed in male reproductive tissues such as the testis, epididymis, prostate, and seminal vesicle. It can facilitate the coronavirus entry into the male reproductive tract, providing an opportunity for its replication. This link between the SARS-CoV-2 and the Grp78 protein could become a therapeutic target to mitigate its harmful effects on male fertility.

The Role of Heat Shock Protein 70 Subfamily in the Hyperplastic Prostate: From Molecular Mechanisms to Therapeutic Opportunities

Benign prostatic hyperplasia (BPH) is one of the most common causes of lower urinary tract symptoms (LUTS) in men, which is characterized by a noncancerous enlargement of the prostate. BPH troubles the vast majority of aging men worldwide; however, the pathogenetic factors of BPH have not been completely identified. The heat shock protein 70 (HSP70) subfamily, which mainly includes HSP70, glucose-regulated protein 78 (GRP78) and GRP75, plays a crucial role in maintaining cellular homeostasis. HSP70s are overexpressed in the course of BPH and involved in a variety of biological processes, such as cell survival and proliferation, cell apoptosis, epithelial/mesenchymal transition (EMT) and fibrosis, contributing to the development and progress of prostate diseases. These chaperone proteins also participate in oxidative stress, a cellular stress response that takes place under stress conditions. In addition, HSP70s can bind to the androgen receptor (AR) and act as a regulator of AR activity. This interaction of HSP70s with AR provides insight into the importance of the HSP70 chaperone family in BPH pathogenesis. In this review, we discuss the function of the HSP70 family in prostate glands and the role of HSP70s in the course of BPH. We also review the potential applications of HSP70s as biomarkers of prostate diseases for targeted therapies.

METTL21A, a Non-Histone Methyltransferase, Is Dispensable for Spermatogenesis and Male Fertility in Mice

Protein methyltransferases play various physiological and pathological roles through methylating histone and non-histone targets. Many histone methyltransferases have been reported to regulate the development of spermatogenic cells. However, the specific function of non-histone methyltransferases during spermatogenesis remains unclear. In this study, we found that METTL21A, a non-histone methyltransferase, is highly expressed in mouse testes. In order to elucidate the role of METTL21A in spermatogenesis, we generated a Mettl21a global knockout mouse model using CRISPR/Cas9 technology. Unexpectedly, our results showed that knockout males are fertile without apparent defects in the processes of male germ cell development, including spermatogonial differentiation, meiosis, and sperm maturation. Furthermore, the ablation of METTL21A does not affect the expression and localization of its known targeting proteins in testes. Together, our data demonstrated that METTL21A is not essential for mouse spermatogenesis and male fertility.

Protective and therapeutic role of melatonin against tunicamycin-induced ER stress in testicular tissue of rats

OBJECTIVES

This study aimed to investigate the possible consequences of administering exogenous melatonin as prevention or treatment against tunicamycin-induced endoplasmic reticulum (ER) stress in the testicular tissue of rats.

MATERIALS AND METHODS

In this study, 42 adult Sprague Dawley rats, randomly divided into seven equal groups, were administered intraperitoneal tunicamycin to induce ER stress. Both prophylactic (PMel) and therapeutic melatonin (TMel) groups were administered melatonin for seven days. ER stress in the cell was detected through immunohistochemical and molecular analyses using GPR78 expression.

RESULTS

Increased oxidant levels and apoptosis rates were shown in testicular tissue because of ER stress. The sections in the melatonin-administered and control groups were similar, with melatonin-administered groups showing an increase in the antioxidant ratio. Histometric examinations revealed both TMel and melatonin applications reduced the diameter of the tubules. However, immunohistochemical and molecular analyses showed that PMel administration decreased the concentration of GRP78 more effectively than TMel.

CONCLUSION

Applying melatonin prior to cell damage occurrence can be recommended for its effectiveness in protecting from tunicamycin-induced ER stress.

Glucose-regulated protein 78 modulates cell growth, epithelial-mesenchymal transition, and oxidative stress in the hyperplastic prostate

Benign prostatic hyperplasia (BPH) is a chronic condition which mainly affects elderly males. Existing scientific evidences have not completely revealed the pathogenesis of BPH. Glucose-regulated protein 78 (GRP78) is a member of the heat shock protein 70 superfamily, which serves as an important regulator in many diseases. This study aims at elucidating the role of GRP78 in the BPH process. Human prostate tissues, cultured human prostate cell lines (BPH-1 and WPMY-1) and clinical data from BPH patients were utilized. The expression and localization of GRP78 were determined with quantitative real time PCR (qRT-PCR), Western blotting and immunofluorescence staining. GRP78 knockdown and overexpression cell models were created with GRP78 siRNA and GRP78 plasmid transfection. With these models, cell viability, apoptosis rate, as well as marker levels for epithelial-mesenchymal transition (EMT) and oxidative stress (OS) were detected by CCK8 assay, flow cytometry analysis and Western blotting respectively. AKT/mTOR and MAPK/ERK pathways were also evaluated. Results showed GRP78 was localized in the epithelium and stroma of the prostate, with higher expression in BPH tissues. There was no significant difference in GRP78 expression between BPH-1 and WPMY-1 cell lines. In addition, GRP78 knockdown (KD) slowed cell growth and induced apoptosis, without effects on the cell cycle stage of both cell lines. Lack of GRP78 affected expression levels of markers for EMT and OS. Consistently, overexpression of GRP78 completely reversed all effects of knocking down GRP78. We further found that GRP78 modulated cell growth and OS via AKT/mTOR signaling, rather than the MAPK/ERK pathway. Overall, our novel data demonstrates that GRP78 plays a significant role in the development of BPH and suggests that GRP78 might be rediscovered as a new target for treatment of BPH.

Heat Shock Factors in Protein Quality Control and Spermatogenesis

Proper regulation of cellular protein quality control is crucial for cellular health. It appears that the protein quality control machinery is subjected to distinct regulation in different cellular contexts such as in somatic cells and in germ cells. Heat shock factors (HSFs) play critical role in the control of quality of cellular proteins through controlling expression of many genes encoding different proteins including those for inducible protein chaperones. Mammalian cells exert distinct mechanism of cellular functions through maintenance of tissue-specific HSFs. Here, we have discussed different HSFs and their functions including those during spermatogenesis. We have also discussed the different heat shock proteins induced by the HSFs and their activities in those contexts. We have also identified several small molecule activators and inhibitors of HSFs from different sources reported so far.

Molecular docking studies of Indian variants of pathophysiological proteins of SARS-CoV-2 with selected drug candidates

SARS-CoV-2 pandemic has recently made the entire world come to a standstill. The number of cases in the world, especially India, have been increasing exponentially. The need of the hour is to assimilate as much data as possible to fast track the pipeline of bringing in new therapeutic tools against this fatal virus. In this brief communication, we aim to throw light on the various variants of the proteins involved heavily in the pathophysiology of COVID-19, namely Spike protein, ACE2, GRP78, TMPRSS2 and NSP-12. We also portray the molecular docking studies of these proteins with specific drugs that are currently being associated with the same. In our brief study, we come across a few key findings. First of all the combinations of the variants of spike protein and ACE2 binding show overall 25% unfavourable ΔΔG. Second, NSP12 is the most mutation prone among all the NSPs of the SARS-CoV-2 genome and the most common mutations are P323L and A97V. Third, we discovered the variants found in the Indian subpopulation that have greater binding with the currently investigated drugs.

Sub-fertility in crossbred bulls: Identification of proteomic alterations in spermatogenic cells using high throughput comparative proteomics approach

The present study was carried out to compare the proteomic profiles of spermatogenic cells of crossbred and zebu cattle in an effort to understand the possible reasons for a higher incidence of sub-fertility in crossbred bulls. The spermatogenic cells collected from the testes of pre-pubertal (6 mo) and adult (24 mo) crossbred and zebu males through fine needle aspiration were proliferated in vitro, and proteomic profiling was done using a shotgun proteomics approach. The age- and species-specific variations in the expression level of proteins were identified in spermatogenic cells. The number of differentially expressed proteins (DEPs) identified in pre-pubertal zebu and crossbred was 546, while 579 DEPs were identified between adult zebu and crossbred bulls. Out of these, 194 DEPS were common to these groups and 40 DEPs displayed a fold change ≥2. However, only 20 proteins exhibited similar expression variation trends (upregulated or downregulated) among pre-pubertal as well as adult zebu and crossbred bulls. Out of these 20 DEPs, 13 proteins were upregulated, and 7 proteins were downregulated in spermatogenic cells of zebu compared to crossbred bulls. Among the upregulated proteins were RPLP2, PAXIP1, calumenin, prosaposin, GTF2F1, TMP2, ubiquitin conjugation factor E4A, COL1A2, vimentin, protein FAM13A, peripherin, GFPT2, and GRP78. Seven proteins that were downregulated in zebu bulls compared to crossbred included APOA1, G patch domain-containing protein 1, NAD P transhydrogenase mitochondrial, glutamyl aminopeptidase, synaptojanin 1 fragment, Arf GAP with SH3 domain ANK repeat and PH domain-containing protein 1, and protein transport protein sec16B. It was inferred that the proteins associated with sperm function and fertilization processes, such as calumenin, prosaposin, vimentin, GRP78, and APOA1 could be studied further to understand the precise cause of subfertility in crossbred bulls.

Targeted inhibition of GRP78 by HA15 promotes apoptosis of lung cancer cells accompanied by ER stress and autophagy

This study investigated the pathophysiological role of GRP78 in the survival of lung cancer cells. Lung cancer patient data from public databases were used to analyze the expression of GRP78 and its influence on prognoses. In vivo, GRP78 protein expression was analyzed in an established urethane-induced lung tumor mouse model. In vitro, the effects of targeted inhibition of GRP78 by HA15 in lung cancer cells were assessed, with cell viability analyzed using a CCK-8 assay, cell proliferation using an EdU assay, apoptosis and cell cycle using flow cytometry, subcellular structure using electron microscopy, and relative mRNA and protein expression using RT-PCR, western blotting or immunofluorescence assays. The results showed that GRP78 was highly expressed in the lung tissue of lung cancer mice model or patients, and was associated with a poor prognosis. After inhibition of GRP78 in lung cancer cells by HA15, cell viability was decreased in a dose- and time-dependent manner, proliferation was suppressed and apoptosis promoted. Unfolded protein response signaling pathway proteins were activated, and the autophagy-related proteins and mRNAs were upregulated. Therefore, targeted inhibition of GRP78 by HA15 promotes apoptosis of lung cancer cells accompanied by ER stress and autophagy.

MiR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine granulosa cells

Background

Granulosa cells (GCs) proliferation and estradiol synthesis significantly affect follicular development. The miR-214-3p expression in the ovarian tissues of high-yielding sows is higher than that in low-yielding sows, indicating that miR-214-3p may be involved in sow fertility. However, the functions and mechanisms of miR-214-3p on GCs are unclear. This study focuses on miR-214-3p in terms of the effects on GCs proliferation and estradiol synthesis.

Results

Our findings revealed that miR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine GCs. MiR-214-3p can increase the percentage of S-phase cells, the number of EdU labeled positive cells, and cell viability. However, E₂ concentration was reduced after miR-214-3p agomir treatment. We also found that miR-214-3p up-regulates the expression of cell cycle genes including cell cycle protein B (Cyclin B), cell cycle protein D (Cyclin D), cell cycle protein E (Cyclin E), and cyclin-dependent kinase 4 (CDK4) at the transcription and translation levels, but down-regulates the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (CYP11A1), cytochrome P450 family 19 subfamily A member 1 (CYP19A1), and steroidogenic acute regulatory protein (StAR) (i.e., the key enzymes in estradiol synthesis). On-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target genes of miR-214-3p in proliferation and estradiol synthesis are Mfn2 and NR5A1, respectively.

Conclusions

Our findings suggest that miR-214-3p plays an important role in the functional regulation of porcine GCs and therefore may be a target gene for regulating follicular development.

Targeting the GRP78 Pathway for Cancer Therapy

The 78-kDa glucose-regulated protein (GRP78) plays an important part in maintaining protein stability, regulating protein folding, and inducing apoptosis autophagy, which is considered as a powerful protein. Meanwhile, it also plays a role in ensuring the normal function of organs. In recent years, more and more researches have been carried out on the targeted therapy of GRP78, mainly focusing on its relevant role in tumor and its role as a major modulator and modulator of subordinate pathways. The ability of GRP78 to respond to endoplasmic reticulum stress (ERS) determines whether tumor cells survive and whether the changes in expression level of GRP78 regulated by endoplasmic reticulum (ER) caused by various factors will directly or indirectly affect cell proliferation, apoptosis, and injury, or reduce the body's defense ability, or have protective effects on various organs.

The Genetic and Endoplasmic Reticulum-Mediated Molecular Mechanisms of Primary Open-Angle Glaucoma

Glaucoma is a heterogenous, chronic, progressive group of eye diseases, which results in irreversible loss of vision. There are several types of glaucoma, whereas the primary open-angle glaucoma (POAG) constitutes the most common type of glaucoma, accounting for three-quarters of all glaucoma cases. The pathological mechanisms leading to POAG pathogenesis are multifactorial and still poorly understood, but it is commonly known that significantly elevated intraocular pressure (IOP) plays a crucial role in POAG pathogenesis. Besides, genetic predisposition and aggregation of abrogated proteins within the endoplasmic reticulum (ER) lumen and subsequent activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent unfolded protein response (UPR) signaling pathway may also constitute important factors for POAG pathogenesis at the molecular level. Glaucoma is commonly known as a ‘silent thief of sight’, as it remains asymptomatic until later stages, and thus its diagnosis is frequently delayed. Thereby, detailed knowledge about the glaucoma pathophysiology is necessary to develop both biochemical and genetic tests to improve its early diagnosis as well as develop a novel, ground-breaking treatment strategy, as currently used medical therapies against glaucoma are limited and may evoke numerous adverse side-effects in patients.

The ameliorative effect of monotropein, astragalin, and spiraeoside on oxidative stress, endoplasmic reticulum stress, and mitochondrial signaling pathway in varicocelized rats

Background

Monotropein, astragalin, and spiraeoside (MAS) are active compounds extracted from medicinal herbs; monotropein from Morinda officinalis How (Rubiaceae), astragalin (kaempferol 3-O-glucoside) from Cuscuta chinensis Lamark (Convolvulaceae) and spiraeoside from the outer scales of Allium cepa L. (Liliceae) in a ratio of 6.69:0.41:3.61. Monotropein, astragalin, and spiraeoside are well-known antioxidants, anti-inflammatory, and antinociceptive agents. The current investigation aims to study the molecular mechanism of varicocele-induced male infertility and the underlying pharmacological mechanisms of MAS.

Methods

Four groups were included: control (CTR), MAS 200 group (MAS 200 mg/kg), varicocele group (VC), and VC + MAS 200 group (MAS 200 mg/kg). Sprague-Dawley (SD) rats were treated with 200 mg/kg MAS or vehicle once daily for 28 days. The possible signaling mechanism and effects of MAS were measured via histological staining, immunohistochemistry, western blot, and biochemical assays.

Results

Parameters such as sperm motility and count, Johnsen’s scores, spermatogenic cell density, serum testosterone, testicular superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and expression of the steroidogenic acute regulatory protein (StAR) improved significantly in the VC + MAS 200 group compared with the VC group. MAS treatment of varicocele-induced group significantly decreased the levels of serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as testicular interleukin-6 (IL6), tumor necrosis factor-α (TNF-α), ROS/RNS, and malondialdehyde (MDA). It also decreased the apoptotic index and reduced the expression of endoplasmic reticulum (ER) protein levels (Grp78, p-IRE1α, and p-JNK) and apoptotic markers such as cleaved caspase-3 and Bax/Bcl2 ratio.

Conclusion

This study suggests that the crosstalk between oxidative stress, ER stress, and mitochondrial pathway mediates varicocele-induced testicular germ cell apoptosis. MAS promotes spermatogenesis in varicocele-induced SD rat, probably by decreasing cytokines (IL-6, TNF-α) levels, regulating abnormal sex hormones, and decreasing oxidative stress, ER stress, and apoptosis.

Expression of glucose-regulated protein 78 as prognostic biomarkers for triple-negative breast cancer

INTRODUCTION

Glucose-regulated protein78(GRP78) is a stress - induced endoplasmic reticulum chaperone protein. it is closely related to the occurrence, development, proliferation, differentiation and drug resistance of breast cancer. However, the association and clinicopathological features between GRP78 and triple negative breast cancer (TNBC) remain to be studied.

MATERIAL AND METHODS

Clinical and pathological characteristics and overall survival were analysed retrospectively in 179 surgically resected TNBC patients. GRP78 was detected by immunohistochemistry (IHC) using breast cancer tissue microarrays (TMAs), and the association between GRP78 levels and clinicopathological factors and prognosis was analyzed. Furthermore, GRP78 expression in human TNBC and NTNBC cell lines was detected by Western blot and qRT-PCR. After Si-GRP78 knocked-down GRP78 in MDA-MB-231 and BT549 cell lines, cell proliferation was detected using Cell Counting Kit-8 (CCK-8) and cell colony formation was detected by crystal violet staining, respectively.

RESULTS

GRP78 was expressed in triple negative breast cancer (TNBC). GRP78 expression was significantly associated with invasive, distant metastasis and proliferation of TNBC (P<0.05). In addition, patients with positive GRP78 expression had shorter overall survival (OS) and disease-free survival (DFS). And the high expression of GRP78 was significantly associated with disease-free survival (DFS) in patients with TNBC (P<0.001).

CONCLUSIONS

These findings improve our understanding of the expression pattern of GRP78 in TNBC and clarify the role of GRP78 as promising prognostic biomarkers for triple-negative breast cancer.