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Journal of Biomedical Science Jun 2024The endoplasmic reticulum (ER) employs stringent quality control mechanisms to ensure the integrity of protein folding, allowing only properly folded, processed and... (Review)
Review
The endoplasmic reticulum (ER) employs stringent quality control mechanisms to ensure the integrity of protein folding, allowing only properly folded, processed and assembled proteins to exit the ER and reach their functional destinations. Mutant proteins unable to attain their correct tertiary conformation or form complexes with their partners are retained in the ER and subsequently degraded through ER-associated protein degradation (ERAD) and associated mechanisms. ER retention contributes to a spectrum of monogenic diseases with diverse modes of inheritance and molecular mechanisms. In autosomal dominant diseases, when mutant proteins get retained in the ER, they can interact with their wild-type counterparts. This interaction may lead to the formation of mixed dimers or aberrant complexes, disrupting their normal trafficking and function in a dominant-negative manner. The combination of ER retention and dominant-negative effects has been frequently documented to cause a significant loss of functional proteins, thereby exacerbating disease severity. This review aims to examine existing literature and provide insights into the impact of dominant-negative effects exerted by mutant proteins retained in the ER in a range of autosomal dominant diseases including skeletal and connective tissue disorders, vascular disorders, neurological disorders, eye disorders and serpinopathies. Most crucially, we aim to emphasize the importance of this area of research, offering substantial potential for understanding the factors influencing phenotypic variability associated with genetic variants. Furthermore, we highlight current and prospective therapeutic approaches targeted at ameliorating the effects of mutations exhibiting dominant-negative effects. These approaches encompass experimental studies exploring treatments and their translation into clinical practice.
Topics: Humans; Endoplasmic Reticulum; Genes, Dominant; Endoplasmic Reticulum-Associated Degradation; Protein Folding; Mutation
PubMed: 38937821
DOI: 10.1186/s12929-024-01054-1 -
Toxicology Mechanisms and Methods Jun 2024Cyclosporine A (CsA) has shown efficacy against immunity-related diseases despite its toxicity in various organs, including the liver, emphasizing the need to elucidate...
Cyclosporine A (CsA) has shown efficacy against immunity-related diseases despite its toxicity in various organs, including the liver, emphasizing the need to elucidate its underlying hepatotoxicity mechanism. This study aimed to capture the alterations in genome-wide expression over time and the subsequent perturbations of corresponding pathways across species. Six data from humans, mice, and rats, including animal liver tissue, human liver microtissues, and two liver cell lines exposed to CsA toxic dose, were used. The microtissue exposed to CsA for 10 d was analyzed to obtain dynamically differentially expressed genes (DEGs). Single-time points data at 1, 3, 5, 7, and 28 d of different species were used to provide additional evidence. Using liver microtissue-based longitudinal design, DEGs that were consistently up- or down-regulated over time were captured, and the well-known mechanism involved in CsA toxicity was elucidated. Thirty DEGs that consistently changed in longitudinal data were also altered in 28-d rat in-house data with concordant expression. Some genes (e.g. , , ) showed good concordance with identified DEGs in 1-d and 7-d mouse data. Pathway analysis revealed up-regulations of protein processing, asparagine N-linked glycosylation, and cargo concentration in the endoplasmic reticulum. Furthermore, the down-regulations of pathways related to biological oxidations and metabolite and lipid metabolism were elucidated. These pathways were also enriched in single-time-point data and conserved across species, implying their biological significance and generalizability. Overall, the human organoids-based longitudinal design coupled with cross-species validation provides temporal molecular change tracking, aiding mechanistic elucidation and biologically relevant biomarker discovery.
PubMed: 38937256
DOI: 10.1080/15376516.2024.2371894 -
The Journal of Neuroscience : the... Jun 2024Many neurons including vasopressin (VP) magnocellular neurosecretory cells (MNCs) of the hypothalamic supraoptic nucleus (SON) generate afterhyperpolarizations (AHPs)...
Many neurons including vasopressin (VP) magnocellular neurosecretory cells (MNCs) of the hypothalamic supraoptic nucleus (SON) generate afterhyperpolarizations (AHPs) during spiking to slow firing, a phenomenon known as spike frequency adaptation. The AHP is underlain by Ca-activated K currents, and while slow component (sAHP) features are well described, its mechanism remains poorly understood. Previous work demonstrated that Ca influx through N-type Ca channels is the primary source of sAHP activation in SON oxytocin neurons, but no obvious channel coupling was described for VP neurons. Given this, we tested the possibility of an intracellular source of sAHP activation, namely the Ca-handling organelles endoplasmic reticulum (ER) and mitochondria in male and female wistar rats. We demonstrate that ER Ca depletion greatly inhibits sAHPs without a corresponding decrease in Ca signal. Caffeine sensitized AHP activation by Ca In contrast to ER, disabling mitochondria with CCCP or blocking mitochondria Ca uniporter (MCU) enhanced sAHP amplitude and duration, implicating mitochondria as a vital buffer for sAHP-activating Ca Block of mitochondria Na-dependent Ca release triphenylphosphonium (TPP) failed to affect sAHPs, indicating that mitochondria Ca doesn't contribute to sAHP activation. Together, our results support that ER Ca-induced Ca release activates sAHPs and mitochondria shape the spatiotemporal trajectory of the sAHP Ca buffering in VP neurons. Overall, this implicates organelle Ca, and specifically ER-mitochondria associated membrane contacts, as an important site of Ca microdomain activity that regulates sAHP signaling pathways. Thus, this site plays a major role in influencing VP firing activity and systemic hormonal release. The slow afterhyperpolarization (sAHP) is mediated by a Ca-dependent K current. Despite its critical role in regulating neuronal spiking, the Ca-dependent mechanisms leading to its activation and spatiotemporal shape remains poorly understood. Here we show that in vasopressin (VP) neurons, dynamic interactions in Ca handling between endoplasmic reticulum (ER) and mitochondria play a significant role in sAHP initiation ( ER Ca release) and its spatiotemporal waveform ( mitochondrial Ca uptake). Our results suggest that contact sites between ER and mitochondria represent Ca microdomains critically involved in initiating the first steps of sAHP generation in VP neurons. Given that changes in the sAHP have been linked to abnormal firing activity in various diseases, our results have both wide-range physiological and pathological implications.
PubMed: 38937101
DOI: 10.1523/JNEUROSCI.0003-24.2024 -
The Science of the Total Environment Jun 2024Crystalline silica (CS) particles are ubiquitously present in the environment, particularly in occupational settings, and exposure to respirable CS causes silicosis,...
Crystalline silica (CS) particles are ubiquitously present in the environment, particularly in occupational settings, and exposure to respirable CS causes silicosis, imposing a significant disease burden. However, the pathogenesis of silicosis remains unclear. Exposure to external stimuli, such as CS, leads to the accumulation of unfolded proteins and triggers endoplasmic reticulum (ER) stress, disrupting tissue immune homeostasis and accelerating pathological progression. While pulmonary macrophages phagocytose CS particles to initiate the immune response, the role of ER stress in this process is unknown. Herein, we used a murine model of silicosis to simulate the pathological progression from acute inflammation to fibrosis in silicosis and conducted in vivo pharmacological inhibition of ER stress to explore the underlying mechanism. Using flow cytometry, we further classified pulmonary macrophages into monocyte-like macrophages (monocytes), interstitial macrophages (IMs), and alveolar macrophages (AMs). Our results showed that CS-induced ER stress primarily contributed to the augmentation of IMs and thereby exerted a significant impact on pulmonary macrophages. Despite coexpressing M1- and M2-like markers, IMs predominantly exhibited an M1-like polarization state and played a proinflammatory role by expressing the cytokines pro-IL-1β and TNF-α during the pathological progression of silicosis. Additionally, IMs recruited by CS-induced ER stress also exhibited high expression of MHCII and exerted active immunomodulatory effects. Overall, our study demonstrates that ER stress induced by CS particles triggers a proinflammatory immune microenvironment dominated by IMs and reveals novel insights into the pulmonary toxicological effects of CS particles.
PubMed: 38936737
DOI: 10.1016/j.scitotenv.2024.174299 -
Life Sciences Jun 2024Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give... (Review)
Review
Membrane trafficking within the Golgi apparatus plays a pivotal role in the intracellular transportation of lipids and proteins. Dysregulation of this process can give rise to various pathological manifestations, including cancer. Exploiting Golgi defects, cancer cells capitalise on aberrant membrane trafficking to facilitate signal transduction, proliferation, invasion, immune modulation, angiogenesis, and metastasis. Despite the identification of several molecular signalling pathways associated with Golgi abnormalities, there remains a lack of approved drugs specifically targeting cancer cells through the manipulation of the Golgi apparatus. In the initial section of this comprehensive review, the focus is directed towards delineating the abnormal Golgi genes and proteins implicated in carcinogenesis. Subsequently, a thorough examination is conducted on the impact of these variations on Golgi function, encompassing aspects such as vesicular trafficking, glycosylation, autophagy, oxidative mechanisms, and pH alterations. Lastly, the review provides a current update on promising Golgi apparatus-targeted inhibitors undergoing preclinical and/or clinical trials, offering insights into their potential as therapeutic interventions. Significantly more effort is required to advance these potential inhibitors to benefit patients in clinical settings.
PubMed: 38936604
DOI: 10.1016/j.lfs.2024.122868 -
Comparative Biochemistry and... Jun 2024The dramatic changes in the global climate pose a major threat to the survival of many organisms, including fish. To date, the regulatory mechanisms behind the...
The dramatic changes in the global climate pose a major threat to the survival of many organisms, including fish. To date, the regulatory mechanisms behind the physiological responses of fish to temperature changes have been studied, and a comprehensive analysis of the regulatory mechanisms of temperature tolerance will help to propose effective strategies for fish to cope with global warming. In this study, we investigated the expression profiles of proteins and metabolites in liver tissues of American shad (Alosa sapidissima) corresponding to different water temperatures (24 °C, 27 °C and 30 °C) at various times (1-month intervals) under natural culture conditions. Proteomic analysis showed that the expression levels of the heat shock protein family (e.g. HSPE1, HSP70, HSPA5 and HSPA.1) increase significantly with temperature and that many differentially expressed proteins were highly enriched especially in pathways related to the endoplasmic reticulum, oxidative phosphorylation and glycolysis/gluconeogenesis processes. In addition, the results of conjoint metabolomics and proteomics analysis suggested that the contents of several important amino acids and chemical compounds, including L-serine, L-isoleucine, L-cystine, choline and betaine, changed significantly under high-temperature environmental stress, affecting the metabolic levels of starch, amino acid and glucose, which is thought to represent a possible energy conservation method for A. sapidissima to cope with rapid changes in external temperature. In summary, our findings demonstrate that living under high temperatures for a long period of time leads to different physiological defense responses in A. sapidissima, which provides some new ideas for analyzing the molecular regulatory patterns of adaptation to high temperature and also provides a theoretical basis for the subsequent improvement of fish culture in response to global warming.
PubMed: 38936462
DOI: 10.1016/j.cbpa.2024.111686 -
ACS Nano Jun 2024Nanoplastics (NPs), as emerging contaminants, have been shown to cause testicular disorders in mammals. However, whether paternal inheritance effects on offspring health...
Nanoplastics (NPs), as emerging contaminants, have been shown to cause testicular disorders in mammals. However, whether paternal inheritance effects on offspring health are involved in NP-induced reproductive toxicity remains unclear. In this study, we developed a mouse model where male mice were administered 200 nm polyethylene nanoparticles (PE-NPs) at a concentration of 2 mg/L through daily gavage for 35 days to evaluate the intergenerational effects of PE-NPs in an exclusive male-lineage transmission paradigm. We observed that paternal exposure to PE-NPs significantly affected growth phenotypes and sex hormone levels and induced histological damage in the testicular tissue of both F and F generations. In addition, consistent changes in sperm count, motility, abnormalities, and gene expression related to endoplasmic reticulum stress, sex hormone synthesis, and spermatogenesis were observed across paternal generations. The upregulation of microRNA (miR)-1983 and the downregulation of miR-122-5p, miR-5100, and miR-6240 were observed in both F and F mice, which may have been influenced by reproductive signaling pathways, as indicated by the RNA sequencing of testis tissues and quantitative real-time polymerase chain reaction findings. Furthermore, alterations in the gut microbiota and subsequent Spearman correlation analysis revealed that an increased abundance of and and a decreased abundance of were positively associated with spermatogenic dysfunction. These findings were validated in a fecal microbiota transplantation trial. Our results demonstrate that changes in miRNAs and the gut microbiota caused by paternal exposure to PE-NPs mediated intergenerational effects, providing deeper insights into mechanisms underlying the impact of paternal inheritance.
PubMed: 38935618
DOI: 10.1021/acsnano.4c06298 -
JCI Insight Jun 2024Endoplasmic reticulum (ER) stress and proinsulin misfolding are heralded as contributing factors to β-cell dysfunction in Type 2 diabetes (T2D), yet how ER function...
Endoplasmic reticulum (ER) stress and proinsulin misfolding are heralded as contributing factors to β-cell dysfunction in Type 2 diabetes (T2D), yet how ER function becomes compromised is not well understood. Recent data identifies altered ER redox homeostasis as a critical mechanism that contributes to insulin granule loss in diabetes. Hyperoxidation of the ER delays proinsulin export and limits the proinsulin supply available for insulin granule formation. In this report, we identified glucose metabolism as a critical determinant in the redox homeostasis of the ER. Using multiple β-cell models, we showed that loss of mitochondrial function or inhibition of cellular metabolism elicited ER hyperoxidation and delayed ER proinsulin export. Our data further demonstrated that β-cell ER redox homeostasis was supported by the metabolic supply of reductive redox donors. We showed that limiting NADPH and thioredoxin flux delayed ER proinsulin export, whereas Txnip suppression restored ER redox and proinsulin trafficking. Taken together, we propose that β-cell ER redox homeostasis is buffered by cellular redox donor cycles, which are maintained through active glucose metabolism.
PubMed: 38935435
DOI: 10.1172/jci.insight.178725 -
Neurotoxicity Research Jun 2024Endoplasmic reticulum (ER) stress and oxidative stress (OS) are often related states in pathological conditions including Parkinson's disease (PD). This study...
Endoplasmic reticulum (ER) stress and oxidative stress (OS) are often related states in pathological conditions including Parkinson's disease (PD). This study investigates the role of anti-oxidant protein paraoxonase 2 (PON2) in ER stress and OS in PD, along with its regulatory molecule. PD was induced in C57BL/6 mice using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) treatment and in SH-SY5Y cells using 1-methyl-4-phenylpyridinium. PON2 was found to be poorly expressed in the substantia nigra pars compacta (SNc) of PD mice, and its overexpression improved motor coordination of mice. Through the evaluation of tyrosine hydroxylase, dopamine transporter, reactive oxygen species (ROS), and C/EBP homologous protein (CHOP) levels and neuronal loss in mice, as well as the examination of CHOP, glucose-regulated protein 94 (GRP94), GRP78, caspase-12, sarco/endoplasmic reticulum calcium ATPase 2, malondialdehyde, and superoxide dismutase levels in SH-SY5Y cells, we observed that PON2 overexpression mitigated ER stress, OS, and neuronal apoptosis both in vivo and in vitro. Forkhead box A1 (FOXA1) was identified as a transcription factor binding to the PON2 promoter to activate its transcription. Upregulation of FOXA1 similarly protected against neuronal loss by alleviating ER stress and OS, while the protective roles were abrogated by additional PON2 silencing. In conclusion, this study demonstrates that FOXA1-mediated transcription of PON2 alleviates ER stress and OS, ultimately reducing neuronal apoptosis in PD.
Topics: Animals; Endoplasmic Reticulum Stress; Oxidative Stress; Mice, Inbred C57BL; Endoplasmic Reticulum Chaperone BiP; Apoptosis; Aryldialkylphosphatase; Humans; Cell Line, Tumor; Male; Mice; Hepatocyte Nuclear Factor 3-alpha; Neurons
PubMed: 38935306
DOI: 10.1007/s12640-024-00709-z -
Molecular Neurobiology Jun 2024Neuroinflammation is a critical pathogenic event following hemorrhagic stroke. Endoplasmic reticulum (ER) stress-induced apoptosis and nucleotide-binding domain,...
Neuroinflammation is a critical pathogenic event following hemorrhagic stroke. Endoplasmic reticulum (ER) stress-induced apoptosis and nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3(NLRP3)-associated pyroptosis can contribute to the escalation of neuroinflammatory responses, leading to increased brain damage. G protein-coupled estrogen receptor 1(GPER1), as the most extensively characterized brain-derived estrogen, was reported to trigger neuroprotective effects. However, the anti-apoptotic and anti-pyroptotic effect of GPER1 activation and the underlying mechanism has not been fully elucidated. We established the experimental SAH model by intravascular perforation. The GPER1 selective agonist G1 was intravenously administered 1 h following SAH. For mechanistic exploration, the selective inhibitor of adenosine monophosphate-activated protein kinase (AMPK), dorsomorphin, was administered via intracerebroventricular injection 30 min prior to SAH induction. Post-SAH assessments included SAH grade, the short-term and long-term neurological outcomes, brain edema, cerebral blood flow, transmission electron microscopy (TEM), western blot (WB), ELISA, TUNEL staining, Fluoro-Jade C staining (FJC), and immunofluorescence staining. The expression of GPER1 was observed to elevate at 6 h and peaked at 24 h subsequent to SAH, predominantly co-localized with neurons. Post-treatment with G1 markedly ameliorated both the short-term and long-term neurological deficits of SAH mouse, as well as inhibiting the expression of neuronal ER stress-associated apoptotic proteins (i.e., CHOP, GRP78, Caspase-12, Cleaved Caspase-3, Bax, Bcl2) and pyroptosis-associated proteins (i.e., NLRP3, ASC, Cleaved Caspase-1). Additionally, our research revealed that inhibition of AMPK with dorsomorphin attenuated the neuroprotective effects of G1. This was accompanied by modifications in the molecular pathways associated with ER stress-induced apoptosis and pyroptosis. These data herein elucidated that GPER1 exerted neuroprotective effects by mitigating neuroinflammation in an AMPK-dependent manner, which modulates neuronal ER stress-associated apoptosis and pyroptosis. Boosting the anti-apoptotic and anti-pyroptotic effect by activating GPER1 may be an efficient treatment strategy for SAH patients.
PubMed: 38935231
DOI: 10.1007/s12035-024-04312-3