The double whammy of ER-retention and dominant-negative effects in numerous autosomal dominant diseases: significance in disease mechanisms and therapy.

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.

Reelin differentially shapes dendrite morphology of medial entorhinal cortical ocean and island cells.

The function of medial entorhinal cortex layer II (MECII) excitatory neurons has been recently explored. MECII dysfunction underlies deficits in spatial navigation and working memory. MECII neurons comprise two major excitatory neuronal populations, pyramidal island and stellate ocean cells, in addition to the inhibitory interneurons. Ocean cells express reelin and surround clusters of island cells that lack reelin expression. The influence of reelin expression by ocean cells and interneurons on their own morphological differentiation and that of MECII island cells has remained unknown. To address this, we used a conditional reelin knockout (RelncKO) mouse to induce reelin deficiency postnatally in vitro and in vivo. Reelin deficiency caused dendritic hypertrophy of ocean cells, interneurons and only proximal dendritic compartments of island cells. Ca2+ recording showed that both cell types exhibited an elevation of calcium frequencies in RelncKO, indicating that the hypertrophic effect is related to excessive Ca2+ signalling. Moreover, pharmacological receptor blockade in RelncKO mouse revealed malfunctioning of GABAB, NMDA and AMPA receptors. Collectively, this study emphasizes the significance of reelin in neuronal growth, and its absence results in dendrite hypertrophy of MECII neurons.

Reelin Regulates Developmental Desynchronization Transition of Neocortical Network Activity.

During the first and second stages of postnatal development, neocortical neurons exhibit a wide range of spontaneous synchronous activity (SSA). Towards the end of the second postnatal week, the SSA is replaced by a more sparse and desynchronized firing pattern. The developmental desynchronization of neocortical spontaneous neuronal activity is thought to be intrinsically generated, since sensory deprivation from the periphery does not affect the time course of this transition. The extracellular protein reelin controls various aspects of neuronal development through multimodular signaling. However, so far it is unclear whether reelin contributes to the developmental desynchronization transition of neocortical neurons. The present study aims to investigate the role of reelin in postnatal cortical developmental desynchronization using a conditional reelin knockout (RelncKO) mouse model. Conditional reelin deficiency was induced during early postnatal development, and Ca2+ recordings were conducted from organotypic cultures (OTCs) of the somatosensory cortex. Our results show that both wild type (wt) and RelncKO exhibited an SSA pattern during the early postnatal week. However, at the end of the second postnatal week, wt OTCs underwent a transition to a desynchronized network activity pattern, while RelncKO activity remained synchronous. This changing activity pattern suggests that reelin is involved in regulating the developmental desynchronization of cortical neuronal network activity. Moreover, the developmental desynchronization impairment observed in RelncKO was rescued when RelncKO OTCs were co-cultured with wt OTCs. Finally, we show that the developmental transition to a desynchronized state at the end of the second postnatal week is not dependent on glutamatergic signaling. Instead, the transition is dependent on GABAAR and GABABR signaling. The results suggest that reelin controls developmental desynchronization through GABAAR and GABABR signaling.

Novel Pathogenic Variants Leading to Sporadic Amyotrophic Lateral Sclerosis in Greek Patients.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive disease that affects motor neurons, leading to paralysis and death usually 3-5 years after the onset of symptoms. The investigation of both sporadic and familial ALS highlighted four main genes that contribute to the pathogenesis of the disease: SOD1, FUS, TARDBP and C9orf72. This study aims to provide a comprehensive investigation of genetic variants found in SOD1, FUS and TARDBP genes in Greek sporadic ALS (sALS) cases. Our sequencing analysis of the coding regions of the abovementioned genes that include the majority of the variants that lead to ALS in 32 sALS patients and 3 healthy relatives revealed 6 variants in SOD1, 19 variants in FUS and 37 variants in TARDBP, of which the SOD1 p.D90A and the FUS c.*356G>A (rs886051940) variants have been previously associated with ALS, while two novel nonsense pathogenic variants were also identified, namely FUS p.R241* and TDP-43 p.Y214*. Our study contributes to the worldwide effort toward clarifying the genetic basis of sALS to better understand the disease's molecular pathology.

The diversity and clinical implications of genetic variants influencing clopidogrel bioactivation and response in the Emirati population.

BACKGROUND: Clopidogrel is a widely prescribed prodrug that requires activation via specific pharmacogenes to exert its anti-platelet function. Genetic variations in the genes encoding its transporter, metabolizing enzymes, and target receptor lead to variability in its activation and platelet inhibition and, consequently, its efficacy. This variability increases the risk of secondary cardiovascular events, and therefore, some variations have been utilized as genetic biomarkers when prescribing clopidogrel. METHODS: Our study examined clopidogrel-related genes (CYP2C19, ABCB1, PON1, and P2Y12R) in a cohort of 298 healthy Emiratis individuals. The study used whole exome sequencing (WES) data to comprehensively analyze pertinent variations of these genes, including their minor allele frequencies, haplotype distribution, and their resulting phenotypes. RESULTS: Our data shows that approximately 37% (n = 119) of the cohort are likely to benefit from the use of alternative anti-platelet drugs due to their classification as intermediate or poor CYP2C19 metabolizers. Additionally, more than 50% of the studied cohort exhibited variants in ABCB1, PON1, and P2YR12 genes, potentially influencing clopidogrel's transport, enzymatic clearance, and receptor performance. CONCLUSIONS: Recognizing these alleles and genotype frequencies may explain the clinical differences in medication response across different ethnicities and predict adverse events. Our findings underscore the need to consider genetic variations in prescribing clopidogrel, with potential implications for implementing personalized anti-platelet therapy among Emiratis based on their genetic profiles.

Utilizing Pharmacogenomic Data for a Safer Use of Statins among the Emirati Population.

BACKGROUND: Statins are the most prescribed lipid-lowering drugs worldwide. The associated adverse events, especially muscle symptoms, have been frequently reported despite their perceived safety. Three pharmacogenes, the solute carrier organic anion transporter family member 1B1 (SLCO1B1), ATP-binding cassette subfamily G member 2 (ABCG2), and cytochrome P450 2C9 (CYP2C9) are suggested as safety biomarkers for statins. The Clinical Pharmacogenomic Implementation Consortium (CPIC) issued clinical guidelines for statin use based on these three genes. OBJECTIVES: The present study aimed to examine variants in these pharmacogenes to predict the safety of statin use among the Emirati population. METHODS: Analyzing 242 whole exome sequencing data at the three genes enabled the determination of the frequencies of the single nucleotide polymorphisms (SNPs), annotating the haplotypes and the predicted functions of their proteins. RESULTS: In our cohort, 29.8% and 5.4% had SLCO1B1 decreased and poor function, respectively. The high frequency warns of the possibility of significant side effects of some statins and the importance of pharmacogenomic testing. We found a low frequency (6%) of the ABCG2:rs2231142 variant, which indicates the low probability of Emirati patients being recommended against higher rosuvastatin doses compared with other populations with higher frequencies of this variant. In contrast, we found high frequencies of the functionally impaired CYP2C9 alleles, which makes fluvastatin a less favorable choice. CONCLUSION: Among the sparse studies available, the present one demonstrates all SLCO1B1 and CYP2C9 function-impairing alleles among Emiratis. We highlighted how population-specific pharmacogenomic data can predict safer choices of statins, especially in understudied populations.

Endoglin mutants retained in the endoplasmic reticulum exacerbate loss of function in hereditary hemorrhagic telangiectasia type 1 (HHT1) by exerting dominant negative effects on the wild type allele.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder affecting 1 in 5000-8000 individuals. Hereditary hemorrhagic telangiectasia type 1 (HHT1) is the most common HHT and manifests as diverse vascular malformations ranging from mild symptoms such as epistaxis and mucosal and cutaneous telangiectases to severe arteriovenous malformations (AVMs) in the lungs, brain or liver. HHT1 is caused by heterozygous mutations in the ENG gene, which encodes endoglin, the TGFß homodimeric co-receptor. It was previously shown that some endoglin HHT1-causing variants failed to traffic to the plasma membrane due to their retention in the endoplasmic reticulum (ER) and consequent degradation by ER-associated degradation (ERAD). Endoglin is a homodimer formed in the ER, and we therefore hypothesized that mixed heterodimers might form between ER-retained variants and WT protein, thus hampering its maturation and trafficking to the plasma membrane causing dominant negative effects. Indeed, HA-tagged ER-retained mutants formed heterodimers with Myc-tagged WT endoglin. Moreover, variants L32R, V105D, P165L, I271N and C363Y adversely affected the trafficking of WT endoglin by reducing its maturation and plasma membrane localization. These results strongly suggest dominant negative effects exerted by these ER-retained variants aggravating endoglin loss of function in patients expressing them in the heterozygous state with the WT allele. Moreover, this study may help explain some of the variability observed among HHT1 patients due to the additional loss of function exerted by the dominant negative effects in addition to that due to haploinsufficiency. These findings might also have implications for some of the many conditions impacted by ERAD.

Discovery of pyrimidoindol and benzylpyrrolyl inhibitors targeting SARS-CoV-2 main protease (Mpro) through pharmacophore modelling, covalent docking, and biological evaluation.

The main protease (Mpro) enzyme has an imperative function in disease progression and the life cycle of the SARS-CoV-2 virus. Although the orally active drug nirmatrelvir (co-administered with ritonavir as paxlovid) has been approved for emergency use as the frontline antiviral agent, there are a number of limitations that necessitate the discovery of new drug scaffolds, such as poor pharmacokinetics and susceptibility to proteolytic degradation due to its peptidomimetic nature. This study utilized a novel virtual screening workflow that combines pharmacophore modelling, multiple-receptor covalent docking, and biological evaluation in order to find new Mpro inhibitors. After filtering and analysing ∼66,000 ligands from three different electrophilic libraries, 29 compounds were shortlisted for experimental testing, and two of them exhibited ≥20% inhibition at 100 µM. Our top candidate, GF04, is a benzylpyrrolyl compound that exhibited the highest inhibition activity of 38.3%, with a relatively small size (<350 Da) and leadlike character. Interestingly, our approach also identified another hit, DR07, a pyrimidoindol with a non-peptide character, and a molecular weight of 438.9 Da, reporting an inhibition of 26.3%. The established approach detailed in this study, in conjunction with the discovered inhibitors, has the capacity to yield novel perspectives for devising covalent inhibitors targeting the COVID-19 Mpro enzyme and other comparable targets.

Unveiling the pathogenic mechanisms of NPR2 missense variants: insights into the genotype-associated severity in acromesomelic dysplasia and short stature.

Introduction: Natriuretic peptide receptor 2 (NPR2 or NPR-B) plays a central role in growth development and bone morphogenesis and therefore loss-of-function variations in NPR2 gene have been reported to cause Acromesomelic Dysplasia, Maroteaux type 1 and short stature. While several hypotheses have been proposed to underlie the pathogenic mechanisms responsible for these conditions, the exact mechanisms, and functional characteristics of many of those variants and their correlations with the clinical manifestations have not been fully established. Methods: In this study, we examined eight NPR2 genetic missense variants (p.Leu51Pro, p.Gly123Val, p.Leu314Arg, p.Arg318Gly, p.Arg388Gln, p.Arg495Cys, p.Arg557His, and p.Arg932Cys) Acromesomelic Dysplasia, Maroteaux type 1 and short stature located on diverse domains and broadly classified as variants of uncertain significance. The evaluated variants are either reported in patients with acromesomelic dysplasia in the homozygous state or short stature in the heterozygous state. Our investigation included the evaluation of their expression, subcellular trafficking and localization, N-glycosylation profiles, and cyclic guanosine monophosphate (cGMP) production activity. Results and Discussion: Our results indicate that variants p.Leu51Pro, p.Gly123Val, p.Leu314Arg, p.Arg388Gln have defective cellular trafficking, being sequestered within the endoplasmic reticulum (ER), and consequently impaired cGMP production ability. Conversely, variants p.Arg318Gly, p.Arg495Cys, and p.Arg557His seem to display a non-statistically significant behavior that is slightly comparable to WT-NPR2. On the other hand, p.Arg932Cys which is located within the guanylyl cyclase active site displayed normal cellular trafficking profile albeit with defective cGMP. Collectively, our data highlights the genotype-phenotype relationship that might be responsible for the milder symptoms observed in short stature compared to acromesomelic dysplasia. This study enhances our understanding of the functional consequences of several NPR2 variants, shedding light on their mechanisms and roles in related genetic disorders which might also help in their pathogenicity re-classification.

A review of genetic variant databases and machine learning tools for predicting the pathogenicity of breast cancer.

Studies continue to uncover contributing risk factors for breast cancer (BC) development including genetic variants. Advances in machine learning and big data generated from genetic sequencing can now be used for predicting BC pathogenicity. However, it is unclear which tool developed for pathogenicity prediction is most suited for predicting the impact and pathogenicity of variant effects. A significant challenge is to determine the most suitable data source for each tool since different tools can yield different prediction results with different data inputs. To this end, this work reviews genetic variant databases and tools used specifically for the prediction of BC pathogenicity. We provide a description of existing genetic variants databases and, where appropriate, the diseases for which they have been established. Through example, we illustrate how they can be used for prediction of BC pathogenicity and discuss their associated advantages and disadvantages. We conclude that the tools that are specialized by training on multiple diverse datasets from different databases for the same disease have enhanced accuracy and specificity and are thereby more helpful to the clinicians in predicting and diagnosing BC as early as possible.

Extracellular molecular signals shaping dendrite architecture during brain development.

Proper growth and branching of dendrites are crucial for adequate central nervous system (CNS) functioning. The neuronal dendritic geometry determines the mode and quality of information processing. Any defects in dendrite development will disrupt neuronal circuit formation, affecting brain function. Besides cell-intrinsic programmes, extrinsic factors regulate various aspects of dendritic development. Among these extrinsic factors are extracellular molecular signals which can shape the dendrite architecture during early development. This review will focus on extrinsic factors regulating dendritic growth during early neuronal development, including neurotransmitters, neurotrophins, extracellular matrix proteins, contact-mediated ligands, and secreted and diffusible cues. How these extracellular molecular signals contribute to dendritic growth has been investigated in developing nervous systems using different species, different areas within the CNS, and different neuronal types. The response of the dendritic tree to these extracellular molecular signals can result in growth-promoting or growth-limiting effects, and it depends on the receptor subtype, receptor quantity, receptor efficiency, the animal model used, the developmental time windows, and finally, the targeted signal cascade. This article reviews our current understanding of the role of various extracellular signals in the establishment of the architecture of the dendrites.

Antihypertensives associated adverse events: a review of mechanisms and pharmacogenomic biomarkers available evidence in multi-ethnic populations.

Hypertension remains a significant health burden worldwide, re-emphasizing the outstanding need for more effective and safer antihypertensive therapeutic approaches. Genetic variation contributes significantly to interindividual variability in treatment response and adverse events, suggesting pharmacogenomics as a major approach to optimize such therapy. This review examines the molecular mechanisms underlying antihypertensives-associated adverse events and surveys existing research on pharmacogenomic biomarkers associated with these events. The current literature revealed limited conclusive evidence supporting the use of genetic variants as reliable indicators of antihypertensive adverse events. However, several noteworthy associations have emerged, such as 1) the role of ACE variants in increasing the risk of multiple adverse events, 2) the bradykinin pathway's involvement in cough induced by ACE inhibitors, and 3) the impact of CYP2D6 variants on metoprolol-induced bradycardia. Nonetheless, challenges persist in identifying biomarkers for adverse events across different antihypertensive classes, sometimes due to the rarity of certain events, such as ACE inhibitors-induced angioedema. We also highlight the main limitations of previous studies that warrant attention, including using a targeted gene approach with a limited number of tested variants, small sample sizes, and design issues such as overlooking doses or the time between starting treatment and the onset of adverse events. Addressing these challenges requires collaborative efforts and the integration of technological advancements, such as next-generation sequencing, which can significantly enhance research outcomes and provide the needed evidence. Furthermore, the potential combination of genomic biomarker identification and machine learning is a promising approach for tailoring antihypertensive therapy to individual patients, thereby mitigating the risk of developing adverse events. In conclusion, a deeper understanding of the mechanisms and the pharmacogenomics of adverse events in antihypertensive therapy will likely pave the way for more personalized treatment strategies to improve patient outcomes.

The Discovery of Novel Small Oxindole-Based Inhibitors Targeting the SARS-CoV-2 Main Protease (Mpro ).

With the potential for coronaviruses to re-emerge and trigger future pandemics, the urgent development of antiviral inhibitors against SARS-CoV-2 is essential. The Mpro enzyme is crucial for disease progression and the virus's life cycle. It possesses allosteric sites that can hinder its catalytic activity, with some of these sites located at or near the dimerization interface. Among them, sites #2 and #5 possess druggable pockets and are predicted to bind drug-like molecules. Consequently, a commercially available ligand library containing ~7 million ligands was used to target site #2 via structure-based virtual screening. After extensive filtering, docking, and post-docking analyses, 53 compounds were chosen for biological testing. An oxindole derivative was identified as a Mpro non-competitive reversible inhibitor with a Ki of 115 µM and an IC50 of 101.9 µM. Throughout the 200 ns-long MD trajectories, our top hit has shown a very stable binding mode, forming several interactions with residues in sites #2 and #5. Moreover, derivatives of our top hit were acquired for biological testing to gain deeper insights into their structure-activity relationship. To sum up, drug-like allosteric inhibitors seem promising and can provide us with an additional weapon in our war against the recent pandemic, and possibly other coronaviruses-caused diseases.

A review of pharmacogenomics studies assessing the knowledge and attitudes of physicians and pharmacists across the Arab and Middle Eastern Region

The principal goal of pharmacogenomics (PGx) is to achieve the highest drug efficacy while maintaining a low toxicity profile. Historically, health care systems used to target treatment for all individuals with the same diagnosis using a standardized medication or dose that fits all. However, a recent pattern in medicine has emerged focusing on personalized and precision medicine. For effective implementation of PGx, there is a need for more collaborations between all the stakeholders in the healthcare system to integrate the pharmacogenetics concept into practice. When it comes to the knowledge and attitudes towards pharmacogenomics, the majority of medical professionals, including pharmacists and physicians, appear to lack appropriate knowledge and training. Across the Middle East and Arab Region, only few studies have addressed this topic. The current review objective is to shed light on pharmacists’ and physicians’ knowledge and attitudes towards PGx practice in the UAE, Arab and the Middle East region as compared to the rest of the world. Moreover, highlighting the role of the pharmacists in the application of PGx services and the educational challenges that are faced. Proposed solutions to improve the knowledge gaps will also be discussed. We also aim to provide the international readers as well as the local researchers with a summary of the trends and distribution of the results across these countries. (AU)

Genotoxicity of Occupational Pesticide Exposures among Agricultural Workers in Arab Countries: A Systematic Review and Meta-Analysis.

Exposure to pesticides in Arab countries is a significant public health concern due to extensive agricultural activity and pesticide use. This systematic review aimed to evaluate the genotoxic effects of agricultural pesticide exposure in the region, identify research gaps, and assess methodological limitations. Following the PRISMA guidelines, a comprehensive search yielded five relevant studies conducted in Egypt, Syria, and Jordan. Various genotoxicity assays were employed, revealing a higher level of DNA damage in exposed compared to non-exposed individuals. Farmers exposed to pesticides exhibited a significantly higher occurrence of chromosomal translocation (t(14;18)), micronuclei, and chromosomal aberrations. However, only two studies assessed cytotoxicity indirectly. The studies predominantly focused on male participants, with variations in sample size and pesticide types. The lack of detailed exposure data necessitates cautious interpretation. This review underscores the need for further research on the genotoxicity of occupational pesticide exposure in the Middle East. Future studies should adopt robust study designs, collect biological and environmental samples, conduct repeated sampling, analyze seasonal variations, and encompass diverse study sites associated with specific crop groups.

Knowledge, attitudes, and perceptions of the multi-ethnic population of the United Arab Emirates on genomic medicine and genetic testing.

INTRODUCTION: The adoption and implementation of genomic medicine and pharmacogenomics (PGx) in healthcare systems have been very slow and limited worldwide. Major barriers to knowledge translation into clinical practice lie in the level of literacy of the public of genetics and genomics. The aim of this study was to assess the knowledge, attitudes, and perceptions of the United Arab Emirates (UAE) multi-ethnic communities toward genomic medicine and genetic testing. METHOD: A cross-sectional study using validated questionnaires was distributed to the participants. Descriptive statistics were performed, and multivariable logistic regression models were used to identify factors associated with knowledge of genomics. RESULTS: 757 individuals completed the survey. Only 7% of the participants had a good knowledge level in genetics and genomics (95% CI 5.3-9.0%). However, 76.9% of the participants were willing to take a genetic test if their relatives had a genetic disease. In addition, the majority indicated that they would disclose their genetic test results to their spouses (61.5%) and siblings (53.4%). CONCLUSIONS: This study sets the stage for the stakeholders to plan health promotion and educational campaigns to improve the genomic literacy of the community of the UAE as part of their efforts for implementing precision and personalized medicine in the country.

The Utility of CYP2D6 and CYP2C19 Variants to Guide Pharmacological Treatment in Complex Unipolar Major Depression: A Pilot Longitudinal Study.

Major depression is a frequent condition which variably responds to treatment. In view of its high prevalence, the presence of treatment resistance in major depression significantly impacts on quality of life. Tailoring pharmacological treatment based on genetic polymorphisms is a current trend to personalizing pharmacological treatment in patients with major depressive disorders. Current guidelines for the use of genetic tests in major depression issued by the Clinical Pharmacogenomics Implementation Consortium (CPIC) are based on CYP2D6 and CYP2C19 polymorphisms which constitute the strongest evidence for pharmacogenomic guided treatment. There is evidence of increased clinical response to pharmacological treatment in major depression although largely in non-treatment resistant patients from Western countries. In this study, well characterised participants (N = 15) with complex, largely treatment resistant unipolar major depression were investigated, and clinical improvement was measured at baseline and at week-8 after the pharmacogenomics-guided treatment with the Montgomery Åsberg Depression Rating Scale (MÅDRS). Results suggested a statistically significant improvement (p = 0.01) of 16% at endpoint in the whole group and a larger effect in case of changes in medication regime (28%, p = 0.004). This small but appreciable effect can be understood in the context of the level of treatment resistance in the group. To our knowledge, this is the first study from the Middle East demonstrating the feasibility of this approach in the treatment of complex major depressive disorders.

Introducing and Implementing Genetic Assessment in Cardio-Obstetrics Clinical Practice: Clinical and Genetic Workup of Patients with Cardiomyopathy.

Cardiovascular disease (CVD) during pregnancy varies significantly worldwide, influenced by factors such as access to healthcare, delayed diagnosis, causes, and risk factors. Our study sought to explore the spectrum of CVD present in pregnant women in the United Arab Emirates to better understand this population's unique needs and challenges. Central to our study is an emphasis on the importance of implementing a multidisciplinary approach that involves the collaboration of obstetricians, cardiologists, geneticists, and other healthcare professionals to ensure that patients receive comprehensive and coordinated care. This approach can also help identify high-risk patients and implement preventive measures to reduce the occurrence of adverse maternal outcomes. Furthermore, increasing awareness among women about the risk of CVD during pregnancy and obtaining detailed family histories can help in the early identification and management of these conditions. Genetic testing and family screening can also aid in identifying inherited CVD that can be passed down through families. To illustrate the significance of such an approach, we provide a comprehensive analysis of five women's cases from our retrospective study of 800 women. The findings from our study emphasize the importance of addressing maternal cardiac health in pregnancy and the need for targeted interventions and improvements in the existing healthcare system to reduce adverse maternal outcomes.

Genetic disruption of mammalian endoplasmic reticulum-associated protein degradation: Human phenotypes and animal and cellular disease models.

Endoplasmic reticulum-associated protein degradation (ERAD) is a stringent quality control mechanism through which misfolded, unassembled and some native proteins are targeted for degradation to maintain appropriate cellular and organelle homeostasis. Several in vitro and in vivo ERAD-related studies have provided mechanistic insights into ERAD pathway activation and its consequent events; however, a majority of these have investigated the effect of ERAD substrates and their consequent diseases affecting the degradation process. In this review, we present all reported human single-gene disorders caused by genetic variation in genes that encode ERAD components rather than their substrates. Additionally, after extensive literature survey, we present various genetically manipulated higher cellular and mammalian animal models that lack specific components involved in various stages of the ERAD pathway.

GRP78/BiP alleviates oxLDL-induced hepatotoxicity in familial hypercholesterolemia caused by missense variants of LDLR in a HepG2 cellular model.

BACKGROUND AND AIMS: The accumulation of misfolded proteins, encoded by genetic variants of functional genes leads to Endoplasmic Reticulum (ER) stress, which is a critical consequence in human disorders such as familial hypercholesterolemia, cardiovascular and hepatic diseases. In addition to the identification of ER stress as a contributing factor to pathogenicity, extensive studies on the role of oxidized Low-Density Lipoprotein (oxLDL) and its ill effects in expediting cardiovascular diseases and other metabolic comorbidities are well documented. However, the current understanding of its role in hepatic insults needs to be revised. This study elucidates the molecular mechanisms underlying the progression of oxLDL and ER stress-induced cytotoxicity in HepG2. METHODS: HepG2 cells stably expressing wild-type Low-Density lipoprotein receptor (WT-LDLR) and missense variants of LDLR that are pathogenically associated with familial hypercholesterolemia were used as the in vitro models. The relative mRNA expression and protein profiles of ER stress sensors, inflammatory and apoptotic markers, together with cytotoxic assays and measurement of mitochondrial membrane potential, were carried out in HepG2 cells treated with 100 µg per ml oxLDL for 24 to 48 h. 1-way or 2-way ANOVA was used for statistical analyses of datasets. RESULTS: ER stress responses are elicited along all three arms of the unfolded protein response (UPR), with adverse cytotoxic and inflammatory responses in oxLDL-treated conditions. Interestingly, oxLDL-treated ER-stressed HepG2 cells manifested intriguingly low expression of BiP- the master regulator of ER stress, as observed earlier by various researchers in liver biopsies of Non-Alcoholic Steatohepatitis (NASH) patients. This study shows that overexpression of BiP rescues hepatic cells from cytotoxic and inflammatory mechanisms instigated by ER stress in combination with oxLDL, along the ER and mitochondrial membrane and restores cellular homeostasis. CONCLUSION: The data provide interesting leads that identify patients with familial hypercholesterolemia conditions and potentially other Endoplasmic Reticulum Associated Degradation (ERAD) diseases as highly susceptible to developing hepatic insults with molecular signatures like those manifested in Non-Alcoholic Fatty Liver Disease (NAFLD) and NASH. LIMITATIONS AND FUTURE PERSPECTIVES: Although the use of HepG2 cells as the model is a major caveat of the study, the findings of this research may be used as the pilot study to expand further investigations in primary hepatocytes or iPSC- derived cellular models.