IRE1

An advanced human heart organoid system can be used to model embryonic heart development under pregestational diabetes-like conditions, researchers report. The organoids recapitulate hallmarks of pregestational diabetes-induced congenital heart disease found in mice and humans. The findings also showed that endoplasmic reticulum (ER) stress and lipid imbalance are critical factors contributing to these disorders, which could be ameliorated with exposure to omega-3s. An advanced human heart organoid system can be used to model embryonic heart development under pregestational diabetes-like conditions, researchers report February 8 in the journal Stem Cell Reports. The organoids recapitulate hallmarks of pregestational diabetes-induced congenital heart disease found in mice and humans. The findings also showed that endoplasmic reticulum (ER) stress and lipid imbalance are critical factors contributing to these disorders, which could be ameliorated with exposure to omega-3s. "The new stem cell-based organoid technology employed will enable physiologically relevant studies in humans, allowing us to bypass animal models and obtain more information about relevant disease mechanisms, accelerating drug discovery and medical translation," says senior study author Aitor Aguirre of Michigan State University. Congenital heart disease is the most common type of congenital defect in humans. Pregestational diabetes -- diabetes affecting the mother before and during the first trimester of pregnancy -- is an important factor contributing to congenital heart disease and is present in a significant, growing population of diabetic female patients of reproductive age. Newborns from mothers with pregestational diabetes can have up to a 12-fold increased risk of congenital heart disease. Unfortunately, pregestational diabetes is hard to manage clinically due to the sensitivity of the developing embryo to glucose oscillations, and it represents a critical health problem for the mother and the fetus. The limited access to human tissues for research of early-stage disease has resulted in an overreliance on animal models. But it remains unclear to what extent rodent models recapitulate abnormalities present in humans, given critical species differences in heart size, cardiac physiology, electrophysiology, and bioenergetics. In addition, rodent models and many in vitro cell models rely on aggressive diabetic conditions, leading to exaggerated features that may not be clinically relevant. "Advances in biotechnology and bioengineering are enabling the creation of human mini-organs in vitro," Aguirre says. "These mini-organs can currently be used to understand human disease much better without the drawbacks of animal models." In the new study, Aguirre and his team used an advanced heart organoid model derived from human pluripotent stem cells. This model recapitulates human heart development during the first trimester, including critical steps such as chamber formation, vascularization, cardiac tissue organization, and relevant cardiac cell types. To specifically model the effects of pregestational diabetes, the researchers modified culture conditions to accurately reflect reported physiological levels of glucose and insulin in patients. The resulting pregestational diabetes heart organoids (PGDHOs) developed features observed in previous mouse and human studies. For example, the diabetic human heart organoids were larger, suggesting signs of cardiac hypertrophy -- a first hallmark of maternal pregestational diabetes. This observation was confirmed by studying cardiomyocyte size. The PGDHOs also displayed arrythmias and a reduction in beat frequency, which has been observed in neonatal rats from diabetic mothers. In addition, single-cell transcriptomic analysis of PGDHOs revealed a reduction in cardiomyocyte numbers, a significant expansion of tissue on the outer surface of the heart, and the absence of a well-developed vasculature at early developmental stages. The PGDHOs also exhibited increased accumulation of reactive oxygen species (ROS), revealing increased oxidative stress and mitochondrial swelling -- also hallmarks of diabetic embryonic heart conditions. A significant portion of ROS was localized to the ER and could be impairing its function, leading to a condition known as ER stress. Moreover, the PGDHOs revealed a clear imbalance in very long chain fatty acids, particularly affecting omega-3 polyunsaturated fatty acids, which are mostly synthesized in the ER. Taken together, these results point to a major ER-induced lipid imbalance in PGDHOs. This imbalance is linked to the degradation of fatty acid desaturase 2 (FADS2) -- a key lipid biosynthesis enzyme presents in the ER -- by the IRE1-dependent mRNA decay (RIDD) pathway, which has been implicated in several other cardiac conditions. In an attempt to remedy the effects of ER stress, the researchers tested several potentially therapeutic compounds on PGDHOs. A mixture of omega-3 fatty acids ameliorated diabetic features, while targeting inositol-requiring enzyme 1 (IRE1) reduced cardiomyocyte hypertrophy. All the compounds also restored FADS2 levels. "The organoids still lack some features that could be important, such as external vascularization and outflow tract, and better chamber formation, so we might still be missing important aspects of congenital heart disease and diabetic cardiomyopathy," Aguirre says. "On one hand, we want to partner with clinicians to establish the efficacy and safety of our findings in pregnant women. On the other hand, we want to apply our organoid model to other conditions affecting congenital heart disease so we can improve the lives of these children in the future." This research was supported by the National Institutes of Health, the National Science Foundation, the Michigan Diabetes Research Center, the University of Michigan, the American Heart Association and the Spectrum-MSU Alliance Foundation.

The GRP78 protein belongs to the HSP70 family of heat shock proteins, which are involved in protein folding. According to cancer biopsy tissues, GRP78 expression is elevated in cancer cells, particularly in hypoxic tumors. Recent studies have also revealed that the protein plays additional roles in the development of cancer tumors. GRP78 does not stop there; it also gives cancer cells the capacity to resist off treatment. For the treatment of numerous diseases, including lung cancer, which causes the greatest number of cancer-related fatalities worldwide, GRP78-targeting has emerged as a possible therapeutic strategy. The protein has also been linked to conditions like COVID-19, where it has been demonstrated to aid the virus in invading the host cells, in addition to cancer. As a result, there is a great deal of therapeutic potential for GRP78 that has to be explored in order to treat disease. Glucose-related protein 78 (GRP78) and other chaperones that are activated by glucose deficiency were discovered in the late 1970s. Stress has been one among the factors promoting its overexpression, albeit its expression varies depending on the tissue type, developmental stage, and stress conditions. Stressed cancer cells overexpress the protein, which travels from the plasma membrane where GRP78 is found to oncogenic pathways that help the tumor survive, grow, and invade. Depletion of glucose, poor blood flow, hypoxia and acidosis are a few stress factors that cause the excessive expression of GRP78, which builds up misfolded polypeptide chains in the endoplasmic reticulum. As a result, the ER transmembrane signal transducers PKR-like ER kinase (PERK), inositol-requiring enzyme 1 (IRE1), and activating transcription factor 6 release GRP78, which in turn initiates the unfolded protein response (ATF6). The ER transmembrane signal transducers strive to decrease the creation of polypeptide chains until the cellular equilibrium is achieved, whereas GRP78 acts in protein folding to preserve homeostasis. Although homozygous GRP78 knockdown results in fetal mortality, it is clear from studies employing GRP78 knockout mice that GRP78 is crucial for embryogenesis. GRP78 heterozygosity resulted in prolonged delay and slowed tumour growth in a transgenic mice model of aggressive metastatic breast cancer Hence, GRP78 heterozygosity is a trustworthy resource for researching the role of GRP78 in the development of human disease. GRP78 has been discovered to have a crucial role in tumour growth, angiogenesis, aggressiveness, dissemination, and chemoresistance in cancer. While GRP78 expression in adult tissues is typically modest in the absence of stress, it is remarkably increased in cancer cells, solid tumors, and human tumor biopsies. Recently, GRP78 was presented as a prostate cancer predictive marker and prospective treatment target. According to research by Fu et al., selective deletion of GRP78 in murine prostate epithelium eliminated prostate cancer and prevented AKT activation without affecting the growth or development of the prostate. If more research investigations are conducted, results from comparable studies imply that the inhibition/deletion/inactivation of GRP78 is a novel, distinct technique for preventing malignancies like prostate cancer in the future. Only Bold Therapeutics and BiPER Therapeutics currently have candidates in the preclinical or clinical stages, according to the global clinical trials database. BOLD-100, a first-in-class clinical stage drug from Bold Therapeutics, is being used to treat advanced malignancies. In a phase I/II trial, it is being assessed in conjunction with FOLFOX for colorectal cancer, pancreatic cancer, gastric malignancies, cholangiocarcinoma, and esophageal squamous cell carcinoma. BOLD-100 phase II trials for multiple myeloma and bladder cancer in combination with other anti-cancer medications are also being planned. The flagship initiative of BiPER Therapeutics, however, is BPR001, a first-in-class small molecule that is now enabling for the IND and targets the GRP78. Although it has serious side effects, chemotherapy is a hopeful treatment option for a number of cancers. Therefore, the creation of novel cancer treatment techniques is unavoidable. GRP78 is steadily becoming a popular topic in the field of cancer research. It is becoming more and more clearer how GRP78 affects the development, progression, and outcomes of different cancers. Having a better understanding of these processes may help us identify additional flaws in tumor cells, which will eventually lead to the creation of innovative treatment approaches. Drugs with innovative therapeutic effect-delivery mechanisms are urgently needed, and GRP78 inhibition is one of these, which has potential in changing the cancer treatment paradigm in the future. Neeraj Chawla Research Head Kuick Research neeraj@kuickresearch.com

Aging and related diseases are associated with alterations in oxidative status and low-grade inflammation, as well as a decreased endoplasmic reticulum (ER) unfolded protein response (UPR). UPR is a functional mechanism by which cells attempt to protect themselves against ER stress. Researchers analyzed these proteins in peripheral blood mononuclear cells of elderly subjects and used computer simulation to predict the key proteins associated with these biomolecules underlying physiological adaptations to exercise. They collected blood samples about five to six days before and after the training period and analyzed various oxidative stress biomarkers in peripheral blood mononuclear cells. The study takes research one step further in helping to elucidate the benefits of exercise in this population. Aging involves a balance between oxidants and antioxidants, low-grade inflammation and a protein response that occurs at the cellular level, which is responsible for many health disorders. Exercise has been shown to regulate the inflammatory response, balance oxidants such as free radicals that build up in the cells and damage DNA; and ameliorate the process by which cells protect themselves against these stressors. Furthermore, resistance training in older adults is recommended to help maintain muscle, flexibility and balance. Aging and related diseases are associated with alterations in oxidative status and low-grade inflammation, as well as a decreased endoplasmic reticulum (ER) unfolded protein response (UPR). UPR is a functional mechanism by which cells attempt to protect themselves against ER stress, resulting from the accumulation of the unfolded/misfolded proteins. One group of proteins associated with the aging process is the mitochondrial heat shock protein 60 (HSP60), which has been demonstrated to play a protective role in the ability for cells to remain active and healthy. Currently, there is limited research investigating the effects of resistance training in older adults on the expression of HSP60 and Klotho, a gene involved in the aging process in mammals. A new study by researchers at Florida Atlantic University, in collaboration with the University of León in Spain, examined whether an eight-week resistance training program would modulate the oxidative status, the UPR activation and key inflammatory pathways as well as their relationships with HSP60 and Klotho proteins. For the study, researchers analyzed these proteins in peripheral blood mononuclear cells of elderly subjects. In addition, they utilized computer simulation to predict the key proteins associated with these biomolecules underlying physiological adaptations to exercise. They collected blood samples approximately five to six days before and after the training period and just before training intervention in young subjects who were included for basal assessments. Researchers also analyzed various oxidative stress biomarkers in peripheral blood mononuclear cells. Results of the study, published in the journal Antioxidants, demonstrated that the levels of the inflammatory proteins (pIRAK1, TLR4, and TRAF6), as well as different markers of the redox balance (catalase, GSH, LP, NRF2, PC, ROS, SOD1, and SOD2) remained unchanged with training. Importantly, untrained elderly subjects showed a significant reduction in pIRE1/IRE1 ratio when compared to trained elderly subjects. Such a finding was further confirmed by a gene ontology analysis, showing that endoplasmic reticulum stress is a key mechanism modulated by IRE1. Additionally, analysis did not show the training effect on the expression of HSP60 and Klotho or their relationships with other outcome variables. Although elderly male and female subjects were included in the training program, researchers did not find any sex effects in the study. These findings might partially support the modulatory effect of resistance training on the endoplasmic reticulum in the elderly. "Regular physical activity is suggested to be an effective intervention in improving age-related diseases such as osteoporosis, sarcopenia or muscle loss and dynapenia or loss of muscle strength, cardiovascular diseases, and type 2 diabetes," said Chun-Jung "Phil" Huang, Ph.D., co-author and a professor in the Department of Exercise Science and Health Promotion within FAU's Charles E. Schmidt College of Science. "Although the beneficial effects of regular physical exercise to alleviate inflammation and oxidative stress are well-established, the processes of these physiological adaptations with regard to protein folding or UPR remains to be explored. That is why we used a systems biology approach for our study." The resistance training protocol for the study consisted of 16 sessions over eight weeks (two sessions per week), with a minimum of 48 hours between sessions. The participants started with a 10-minute warm-up on a cycle ergometer. Subsequently, eight different resistance exercises (leg press, ankle extension, bench press, leg extension, bicep curl, pec deck, high pulley traction, and dumbbell lateral lift) were performed using the exercise device. For each exercise, participants performed three sets of 12-8-12 repetitions. There was a two-to-three-minute rest between each repetition and a three-minute rest between each exercise. "We know how very important physical activity is for older adults and our study takes research one step further in helping to elucidate the benefits of exercise in this population," said Huang. Study co-authors are senior author Brisamar Estébanez, Ph.D.; Marta Rivera-Viloria; and José A. de Paz, M.D., all with the University of León; José E. Vargas, Ph.D., Universidad Federal do Paraná, Curtiba; and Nishant P. Visavadiay, Ph.D.; and Andy V. Kahmoui, Ph.D., both with FAU's Department of Exercise Science and Health Promotion.