CGI1746 targets σ1R to modulate ferroptosis through mitochondria-associated membranes

Ferroptosis meets inflammation: A new frontier in cancer therapy

Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has emerged as a critical player in cancer pathogenesis. Concurrently, inflammation, a key biological response to tissue injury or infection, significantly influences cancer development and progression. The interplay between ferroptosis and inflammation represents a promising yet underexplored area of research. This review synthesizes recent advances in understanding the molecular mechanisms governing their interaction, emphasizing how ferroptosis triggers inflammatory responses and how inflammatory mediators, such as TNF-α, regulate ferroptosis through iron metabolism and lipid peroxidation pathways. Key molecular targets within the ferroptosis-inflammation axis, including GPX4, ACSL4, and the NF-κB signaling pathway, offer therapeutic potential for cancer treatment. By modulating these targets, it may be possible to enhance ferroptosis and fine-tune inflammatory responses, thereby improving therapeutic outcomes. Additionally, this review explores the broader implications of targeting the ferroptosis-inflammation interplay in disease treatment, highlighting opportunities for developing innovative strategies to combat cancer. By bridging the gap in current knowledge, this review provides a comprehensive resource for researchers and clinicians, offering insights into the therapeutic potential of this intricate biological relationship.

PFOS exposure impairs porcine oocyte maturation and embryo development via mitochondria-dependent ferroptosis

Perfluorooctane sulfonate (PFOS) is a widely utilized chemical known for its exceptional environmental stability over extended periods, its significant potential to bioaccumulate in living organisms, and its considerable risks to both health and the environment. Several studies have suggested that PFOS may pose reproductive risks in mammals; however, the exact mechanisms driving these effects are not well understood. In this study, we explored the possible mechanisms by which PFOS toxicity affects the maturation of mammalian oocytes and the embryonic development employing porcine oocytes as a model system. SMART-seq results suggested that PFOS may affect oocyte maturation through mechanisms involving ferroptosis, autophagy, and alterations in membrane structure. Our results suggest that PFOS exposure adversely affects mitochondrial function and structure, thereby influencing peroxisome biogenesis and contributing to oxidative stress. Most importantly, we found that exposure to PFOS significantly elevated Fe2+ levels, an indicator associated with ferroptosis in oocytes. Furthermore, malondialdehyde (MDA) levels in the PFOS group were significantly higher than those in the control group. Additionally, the mRNA expression levels of PCBP1 and PCBP2, which are related to ferroptosis, as well as the expression level of P53, were significantly reduced in the PFOS group. Overall, exposure to PFOS in vitro results in mitochondrial damage in porcine oocytes, which induces lipid peroxidation and subsequently leads to the occurrence of ferroptosis.

A Novel Compound 3a-M1, from Metabolites of Sinomenine Derivative 3a, Exerts Potent Anti-Aplastic Anemia Activity via IP3R/ORAI-Mediated CTL Ferroptosis

Aplastic anemia (AA) is a refractory hematological disease with limited therapeutic effectiveness and serious treatment-related side effects. Cytotoxic T lymphocytes (CTLs) play a key role in AA pathogenesis. In our previous study, sinomenine derivative 3a was obtained, which demonstrated potential anti-AA activity by targeting CTLs with low toxicity. In this study, a novel metabolite, 3a-M1, was identified with optimized bioavailability from 3a metabolism, which exhibited a more notable effect in alleviating anemia symptoms, suppressing bone marrow CTLs activation, and improving hematopoietic function in immune-mediated bone marrow failure mouse models. In vitro experiments demonstrated that 3a-M1 directly inhibited CTLs activation and their killing function; the underlying mechanism was at least in part mediated by the selective ferroptosis of overactivated CTLs via the IP3R/ORAI pathway. These findings suggest that 3a-M1 represents a novel potential therapeutic agent for AA treatment and ferroptosis may serve as a promising target on CTLs for AA therapy.

GPAT4 sustains endoplasmic reticulum homeostasis in endocardial cells and safeguards heart development

The endocardium plays a pivotal role in governing myocardial development, and understanding the intrinsic regulatory insights will help apprehend pathological cardiomyopathy. Glycerol-3-phosphate acyltransferase 4 (GPAT4) is an endoplasmic reticulum (ER) membrane anchored protein. While the role of GPAT4 in glycerophospholipid biosynthesis is well established, its function in the ER is less explored. Here, we generate Gpat4 global and tissue-specific knockout mice and identify the essential role of GPAT4 in endocardial development. Deficiency of GPAT4 provokes endocardial ER stress response and enhances ER-mitochondrial (ER-mito) communications, leading to mitochondrial DNA (mtDNA) escape. As a result, the cGAS-STING pathway is triggered to stimulate type-I-interferon response, which affects heart development. Finally, abolishment of the cGAS-STING-type-I-interferon pathway rescues the heart defects of Gpat4 deletion mice. These findings uncover the pivotal role of GPAT4 in the maintenance of ER homeostasis during endocardial and heart development. Meanwhile, this study highlights the importance of the cGAS-STING pathway in cardiac organogenesis.

Parkinson's Disease: The Neurodegenerative Enigma Under the "Undercurrent" of Endoplasmic Reticulum Stress

Parkinson's disease (PD), a prevalent neurodegenerative disorder, demonstrates the critical involvement of endoplasmic reticulum stress (ERS) in its pathogenesis. This review comprehensively examines the role and molecular mechanisms of ERS in PD. ERS represents a cellular stress response triggered by imbalances in endoplasmic reticulum (ER) homeostasis, induced by factors such as hypoxia and misfolded protein aggregation, which activate the unfolded protein response (UPR) through the inositol-requiring enzyme 1 (IRE1), protein kinase R-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) pathways. Clinical, animal model, and cellular studies have consistently demonstrated a strong association between PD and ERS. Abnormal expression of ERS-related molecules in PD patients' brains and cerebrospinal fluid (CSF) correlates with disease progression. In animal models (e.g., Drosophila and mice), ERS inhibition alleviates dopaminergic neuronal damage. Cellular experiments reveal that PD-mimicking pathological conditions induce ERS, while interactions between ERS and mitochondrial dysfunction promote neuronal apoptosis. Mechanistically, (1) pathological aggregation of α-synuclein (α-syn) and ERS mutually reinforce dopaminergic neuron damage; (2) leucine-rich repeat kinase 2 (LRRK2) gene mutations induce ERS through thrombospondin-1 (THBS1)/transforming growth factor beta 1 (TGF-β1) interactions; (3) molecules such as Parkin and PTEN-induced kinase 1 (PINK1) regulate ERS in PD. Furthermore, ERS interacts with mitochondrial dysfunction, oxidative stress, and neuroinflammation to exacerbate neuronal injury. Emerging therapeutic strategies show significant potential, including artificial intelligence (AI)-assisted drug design targeting ERS pathways and precision medicine approaches exploring non-pharmacological interventions such as personalized electroacupuncture. Future research should focus on elucidating ERS-related mechanisms and identifying novel therapeutic targets to develop more effective treatments for PD patients, ultimately improving their quality of life.

From mechanisms to medicine: Ferroptosis as a Therapeutic target in liver disorders

In recent 10 years, ferroptosis has become a hot research direction in the scientific research community as a new way of cell death. Iron toxicity accumulation and lipotoxicity are unique features. Several studies have found that ferroptosis is involved in the regulation of the hepatic microenvironment and various hepatic metabolisms, thereby mediating the progression of related liver diseases. For example, NRF2 and FSP1, as important regulatory proteins of ferroptosis, are involved in the development of liver tumors and liver failure. In this manuscript, we present the mechanisms involved in ferroptosis, the concern of ferroptosis with the liver microenvironment and the progression of ferroptosis in various liver diseases. In addition, we summarize recent clinical advances in targeted ferroptosis therapy for related diseases. We expect that this manuscript can provide a new perspective for clinical treatment of related diseases.

AKAP1/PKA-mediated GRP75 phosphorylation at mitochondria-associated endoplasmic reticulum membranes protects cancer cells against ferroptosis

Emerging evidence suggests that signaling pathways can be spatially regulated to ensure rapid and efficient responses to dynamically changing local cues. Ferroptosis is a recently defined form of lipid peroxidation-driven cell death. Although the molecular mechanisms underlying ferroptosis are emerging, spatial aspects of its signaling remain largely unexplored. By analyzing a public database, we found that a mitochondrial chaperone protein, glucose-regulated protein 75 (GRP75), may have a previously undefined role in regulating ferroptosis. This was subsequently validated. Interestingly, under ferroptotic conditions, GRP75 translocated from mitochondria to mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) and the cytosol. Further mechanistic studies revealed a highly spatial regulation of GRP75-mediated antiferroptotic signaling. Under ferroptotic conditions, lipid peroxidation predominantly accumulated at the ER, which activated protein kinase A (PKA) in a cAMP-dependent manner. In particular, a signaling microdomain, the outer mitochondrial membrane protein A-kinase anchor protein 1 (AKAP1)-anchored PKA, phosphorylated GRP75 at S148 in MAMs. This caused GRP75 to be sequestered outside the mitochondria, where it competed with Nrf2 for Keap1 binding through a conserved high-affinity RGD-binding motif, ETGE. Nrf2 was then stabilized and activated, leading to the transcriptional activation of a panel of antiferroptotic genes. Blockade of the PKA/GRP75 axis dramatically increased the responses of cancer cells to ferroptosis both in vivo and in vitro. Our identification a localized signaling cascade involved in protecting cancer cells from ferroptosis broadens our understanding of cellular defense mechanisms against ferroptosis and also provides a new target axis (AKAP1/PKA/GRP75) to improve the responses of cancer cells to ferroptosis.

Eriodictyol-cisplatin coated nanomedicine synergistically promote osteosarcoma cells ferroptosis and chemosensitivity

The ever-increasing chemoresistance of osteosarcoma (OS) has been observed in the recent decades, impeding OS therapeutic improvement and posing an urgency to exploit to the alternative and/or supplementary therapies for the optimization of OS chemotherapeutic regimen. Ferroptosis, a regulated cell death, has been identified as a natural anticancer mechanism as well as a synergist for chemotherapeutics in various cancers. Herein, we affirmed the tumor-suppressing properties of eriodictyol and illustrated that its antitumor effects might ascribe to the ferroptosis-inducing activity, in which eriodictyol could bind with BACH1 to repress the transcription and translation of GPX4 and eventually result in the GPX4-related ferroptosis. Further investigation found that eriodictyol could exhibit a synergistic effect with cisplatin, facilitating the antitumor effects of cisplatin. Lastly, through utilizing hollow mesoporous prussian blue nanocubes loaded with eriodictyol and cisplatin, we formed the ferroptosis-synergistic nanocomplexes to facilitate OS cells ferroptosis and cisplatin sensitivity. Through direct catalytic oxidation of unsaturated lipids, exogenous iron delivery, GSH exhaustion, and GPX4 transcriptional inhibition, this ferroptosis-synergistic nanocomplex could excellently enhance OS cells ferroptosis in both vitro and vivo, with no obvious organ injury observed. Therefore, our ferroptosis-synergistic nanocomplex may represent a promising alternative therapeutic strategy for OS patients.

The correlation between mitochondria-associated endoplasmic reticulum membranes (MAMs) and Ca2+ transport in the pathogenesis of diseases

Mitochondria and the endoplasmic reticulum (ER) are vital organelles that influence various cellular physiological and pathological processes. Recent evidence shows that about 5%-20% of the mitochondrial outer membrane is capable of forming a highly dynamic physical connection with the ER, maintained at a distance of 10-30 nm. These interconnections, known as MAMs, represent a relatively conserved structure in eukaryotic cells, acting as a critical platform for material exchange between mitochondria and the ER to maintain various aspects of cellular homeostasis. Particularly, ER-mediated Ca2+ release and recycling are intricately associated with the structure and functionality of MAMs. Thus, MAMs are integral in intracellular Ca2+ transport and the maintenance of Ca2+ homeostasis, playing an essential role in various cellular activities including metabolic regulation, signal transduction, autophagy, and apoptosis. The disruption of MAMs observed in certain pathologies such as cardiovascular and neurodegenerative diseases as well as cancers leads to a disturbance in Ca2+ homeostasis. This imbalance potentially aggravates pathological alterations and disease progression. Consequently, a thorough understanding of the link between MAM-mediated Ca2+ transport and these diseases could unveil new perspectives and therapeutic strategies. This review focuses on the changes in MAMs function during disease progression and their implications in relation to MAM-associated Ca2+ transport.

Oxygen-Independent Photodynamic Therapy-Mediated Selective Consumption of M1 Macrophage Against Ventricular Arrhythmias via Sympathetic Neuromodulation

The occurrence of myocardial infarction (MI)-induced malignant ventricular arrhythmias (VAs) is closely associated with the hyperactivation of left stellate ganglion (LSG). Proinflammatory M1 macrophage is reported to aggravate sympathetic overactivation and cause VAs. Therefore, the depletion of M1 macrophage is anticipated to inhibit LSG overactivation and alleviate MI-induced VAs. Herein, oxygen-independent photodynamic therapy (Oi-PDT) combined with M1 macrophage targeting is applied to selectively deplete M1 macrophage in LSG and further treat MI-induced VAs. Oi-PDT, which overcomes the limitation of extremely dependence on oxygen content in traditional PDT, is constructed through the generation of oxidizing photogenerated holes (h+) under the irradiation of near-infrared (NIR) light on the prepared Oi-PDT agent (PPSCD). Meanwhile, PPSCD targets M1 macrophage through conjunction with SR-A receptor. The selective consumption of M1 macrophage is attributed to both apoptosis and ferroptosis induced by h+, 1O2, and O2 •- generated in Oi-PDT. In vivo tests indicated neural activity experienced a notable reduction from 104.5 ±  2.9 to 51.5 ± 6.7 after MI with Oi-PDT treatment, thereby significantly inhibited VAs. The implementation of this study provides a promising strategy for selective consumption of M1 macrophages and treatment of VAs induced by MI.

Retinal Pigment Epithelium Under Oxidative Stress: Chaperoning Autophagy and Beyond

The structural and functional integrity of the retinal pigment epithelium (RPE) plays a key role in the normal functioning of the visual system. RPE cells are characterized by an efficient system of photoreceptor outer segment phagocytosis, high metabolic activity, and risk of oxidative damage. RPE dysfunction is a common pathological feature in various retinal diseases. Dysregulation of RPE cell proteostasis and redox homeostasis is accompanied by increased reactive oxygen species generation during the impairment of phagocytosis, lysosomal and mitochondrial failure, and an accumulation of waste lipidic and protein aggregates. They are the inducers of RPE dysfunction and can trigger specific pathways of cell death. Autophagy serves as important mechanism in the endogenous defense system, controlling RPE homeostasis and survival under normal conditions and cellular responses under stress conditions through the degradation of intracellular components. Impairment of the autophagy process itself can result in cell death. In this review, we summarize the classical types of oxidative stress-induced autophagy in the RPE with an emphasis on autophagy mediated by molecular chaperones. Heat shock proteins, which represent hubs connecting the life supporting pathways of RPE cells, play a special role in these mechanisms. Regulation of oxidative stress-counteracting autophagy is an essential strategy for protecting the RPE against pathological damage when preventing retinal degenerative disease progression.

Multifaceted interplays between the essential players and lipid peroxidation in ferroptosis

Ferroptosis, a type of programmed cell death, represents a distinct paradigm in cell biology. It is characterized by the iron-dependent accumulation of reactive oxygen species, which induce lipid peroxidation (LPO), and is orchestrated by the interplay between iron, lipid peroxides, and glutathione. In this review, we emphasize the frequently overlooked role of iron in LPO beyond the classical iron-driven Fenton reaction in several crucial processes that regulate cellular iron homeostasis, including iron intake and export as well as ferritinophagy, and the emerging roles of endoplasmic reticulum-resident flavoprotein oxidoreductases, especially P450 oxidoreductases, in modulating LPO. We summarize how various types of fatty acids (FAs), including saturated, monounsaturated, and polyunsaturated FAs, differentially influence ferroptosis when incorporated into phospholipids. Furthermore, we highlight the therapeutic potential of targeting LPO to mitigate ferroptosis and discuss the regulatory mechanisms of endogenous lipophilic radical-trapping antioxidants that confer resistance to ferroptosis, shedding light on therapeutic avenues for ferroptosis-associated diseases.

Deferiprone protects photoreceptors by inhibiting ferroptosis after experimental retinal detachment

The detachment of the retinal neuroepithelium from the retinal pigment epithelium (RPE), often due to a retinal tear and subsequent subretinal fluid (SRF) accumulation, is a critical factor leading to photoreceptor cells (PR) death and permanent vision impairment in retinal detachment (RD) scenarios. Predicting postoperative visual recovery is challenging, even with surgical reattachment. Research has indicated that increased iron and transferrin (TF) saturation in the vitreous fluid (VF) correlates with poorer visual outcomes, suggesting a potential role for ferroptosis, a form of regulated cell death, in PR following RD. To explore this hypothesis, we analyzed the VF of RD patients for ferroptosis markers, revealing reduced levels of glutathione peroxidase 4 (GPX4), glutathione (GSH), and reduced nicotinamide adenine dinucleotide phosphate (NADPH), alongside elevated levels of Long-chain acyl-CoA synthetase 4(ACSL4), malondialdehyde (MDA), and ferrous iron. We then developed a mouse model to simulate RD and administered the iron chelator deferiprone (DFP) as a treatment. Our findings indicated that DFP mitigated ferroptosis in the retina, thereby preserving retinal architecture and function. Collectively, our study establishes the occurrence of ferroptosis in RD and demonstrates the therapeutic potential of DFP in protecting PR and treating RD.

Nuciferine Alleviates High-Fat Diet- and ApoE-/--Induced Hepatic Steatosis and Ferroptosis in NAFLD Mice via the PPARα Signaling Pathway

Nonalcoholic fatty liver disease (NAFLD) causes significant global mortality and healthcare costs with no recommended pharmacological intervention for clinical management. Nuciferine (Nuc) is an alkaloid with aromatic rings, abundantly found in Nelumbo nucifera Gaertn. In this study, we explored the protective mechanisms of Nuc against hepatic steatosis and ferroptosis in NAFLD. High-fat diet (HFD) and healthy male ApoE-/- mice were used to induce NAFLD and a hypercholesterolemia model. Nuc was administered to the mice for four consecutive weeks from the ninth week. Various assessments, including histopathology, RNA sequencing, lipid metabolism, and ferroptosis-related protein expression, showed that Nuc alleviated hepatic steatosis and ferroptosis. We further showed that Nuc improves fatty acid accumulation and ferroptosis through the PPARα signaling pathway in mice and RSL3-treated AML-12 cells. The PPARα inhibitor GW6471 blocked Nuc's protective effects, leading to excess accumulation of iron ions. Thus, Nuc may be a potential therapeutic agent for NAFLD.

Golgi protein ACBD3 downregulation sensitizes cells to ferroptosis

Ferroptosis, a form of cell death driven by iron-dependent lipid peroxidation, is emerging as a promising target in cancer therapy. It is regulated by a network of molecules and pathways that modulate lipid metabolism, iron homeostasis and redox balance, and related processes. However, there are still numerous regulatory molecules intricately involved in ferroptosis that remain to be identified. Here, we indicated that suppression of Golgi protein acyl-coenzyme A binding domain A containing 3 (ACBD3) increased the sensitivity of Henrieta Lacks and PANC1 cells to ferroptosis. ACBD3 knockdown increases labile iron levels by promoting ferritinophagy. This increase in free iron, coupled with reduced levels of glutathione peroxidase 4 due to ACBD3 knockdown, leads to the accumulation of reactive oxygen species and lipid peroxides. Moreover, ACBD3 knockdown also results in elevated levels of polyunsaturated fatty acid-containing glycerophospholipids through mechanisms that remain to be elucidated. Furthermore, inhibition of ferrtinophagy in ACBD3 downregulated cells by knocking down the nuclear receptor co-activator 4 or Bafilomycin A1 treatment impeded ferroptosis. Collectively, our findings highlight the pivotal role of ACBD3 in governing cellular resistance to ferroptosis and suggest that pharmacological manipulation of ACBD3 levels is a promising strategy for cancer therapy.

Ciprofloxacin is a novel anti-ferroptotic antibiotic

Cancer patients undergoing chemotherapy are susceptible to various bacterial infections, necessitating prompt and precise antimicrobial treatment with antibiotics. Ciprofloxacin is a clinically utilized broad-spectrum antimicrobial agent known for its robust antiseptic activity. While ferroptosis, an oxidative form of cell death, has garnered attention as a promising avenue in cancer therapy, the potential impact of ciprofloxacin on the anticancer effects of ferroptosis remains unclear. This study seeks to investigate the potential influence of antibiotics on ferroptosis in human pancreatic ductal adenocarcinoma (PDAC) cells. Here, we report a previously unrecognized role of ciprofloxacin in inhibiting ferroptosis in human PDAC cells. Mechanistically, ciprofloxacin suppresses erastin-induced endoplasmic reticulum (ER) stress through the activating transcription factor 6 (ATF6) and ER to nucleus signaling 1 (ERN1) pathway. Excessive ER stress activation can trigger glutathione peroxidase 4 (GPX4) degradation through autophagic mechanisms. In contrast, ciprofloxacin enhances the protein stability of GPX4, a crucial regulator that suppresses ferroptosis by inhibiting lipid peroxidation. Thus, our study demonstrates the anti-ferroptotic role of ciprofloxacin, highlighting the importance of careful consideration when contemplating the combination of ciprofloxacin with specific ferroptosis inducers in PDAC patients.

Ferroptosis: principles and significance in health and disease

Ferroptosis, an iron-dependent form of cell death characterized by uncontrolled lipid peroxidation, is governed by molecular networks involving diverse molecules and organelles. Since its recognition as a non-apoptotic cell death pathway in 2012, ferroptosis has emerged as a crucial mechanism in numerous physiological and pathological contexts, leading to significant therapeutic advancements across a wide range of diseases. This review summarizes the fundamental molecular mechanisms and regulatory pathways underlying ferroptosis, including both GPX4-dependent and -independent antioxidant mechanisms. Additionally, we examine the involvement of ferroptosis in various pathological conditions, including cancer, neurodegenerative diseases, sepsis, ischemia-reperfusion injury, autoimmune disorders, and metabolic disorders. Specifically, we explore the role of ferroptosis in response to chemotherapy, radiotherapy, immunotherapy, nanotherapy, and targeted therapy. Furthermore, we discuss pharmacological strategies for modulating ferroptosis and potential biomarkers for monitoring this process. Lastly, we elucidate the interplay between ferroptosis and other forms of regulated cell death. Such insights hold promise for advancing our understanding of ferroptosis in the context of human health and disease.

Miro-mediated mitochondrial transport: A new dimension for disease-related abnormal cell metabolism?

Mitochondria are versatile and highly dynamic organelles found in eukaryotic cells that play important roles in a variety of cellular processes. The importance of mitochondrial transport in cell metabolism, including variations in mitochondrial distribution within cells and intercellular transfer, has grown in recent years. Several studies have demonstrated that abnormal mitochondrial transport represents an early pathogenic alteration in a variety of illnesses, emphasizing its significance in disease development and progression. Mitochondrial Rho GTPase (Miro) is a protein found on the outer mitochondrial membrane that is required for cytoskeleton-dependent mitochondrial transport, mitochondrial dynamics (fusion and fission), and mitochondrial Ca2+ homeostasis. Miro, as a critical regulator of mitochondrial transport, has yet to be thoroughly investigated in illness. This review focuses on recent developments in recognizing Miro as a crucial molecule in controlling mitochondrial transport and investigates its roles in diverse illnesses. It also intends to shed light on the possibilities of targeting Miro as a therapeutic method for a variety of diseases.

Ferroptosis mechanisms and regulations in cardiovascular diseases in the past, present, and future

Cardiovascular diseases (CVDs) are the main diseases that endanger human health, and their risk factors contribute to high morbidity and a high rate of hospitalization. Cell death is the most important pathophysiology in CVDs. As one of the cell death mechanisms, ferroptosis is a new form of regulated cell death (RCD) that broadly participates in CVDs (such as myocardial infarction, heart transplantation, atherosclerosis, heart failure, ischaemia/reperfusion (I/R) injury, atrial fibrillation, cardiomyopathy (radiation-induced cardiomyopathy, diabetes cardiomyopathy, sepsis-induced cardiac injury, doxorubicin-induced cardiac injury, iron overload cardiomyopathy, and hypertrophic cardiomyopathy), and pulmonary arterial hypertension), involving in iron regulation, metabolic mechanism and lipid peroxidation. This article reviews recent research on the mechanism and regulation of ferroptosis and its relationship with the occurrence and treatment of CVDs, aiming to provide new ideas and treatment targets for the clinical diagnosis and treatment of CVDs by clarifying the latest progress in CVDs research.

Not So Rare: Diseases Based on Mutant Proteins Controlling Endoplasmic Reticulum-Mitochondria Contact (MERC) Tethering

Mitochondria-endoplasmic reticulum contacts (MERCs), also called endoplasmic reticulum (ER)-mitochondria contact sites (ERMCS), are the membrane domains, where these two organelles exchange lipids, Ca2+ ions, and reactive oxygen species. This crosstalk is a major determinant of cell metabolism, since it allows the ER to control mitochondrial oxidative phosphorylation and the Krebs cycle, while conversely, it allows the mitochondria to provide sufficient ATP to control ER proteostasis. MERC metabolic signaling is under the control of tethers and a multitude of regulatory proteins. Many of these proteins have recently been discovered to give rise to rare diseases if their genes are mutated. Surprisingly, these diseases share important hallmarks and cause neurological defects, sometimes paired with, or replaced by skeletal muscle deficiency. Typical symptoms include developmental delay, intellectual disability, facial dysmorphism and ophthalmologic defects. Seizures, epilepsy, deafness, ataxia, or peripheral neuropathy can also occur upon mutation of a MERC protein. Given that most MERC tethers and regulatory proteins have secondary functions, some MERC protein-based diseases do not fit into this categorization. Typically, however, the proteins affected in those diseases have dominant functions unrelated to their roles in MERCs tethering or their regulation. We are discussing avenues to pharmacologically target genetic diseases leading to MERC defects, based on our novel insight that MERC defects lead to common characteristics in rare diseases. These shared characteristics of MERCs disorders raise the hope that they may allow for similar treatment options.