Citrinin (CTN) is a mycotoxin commonly found in contaminated foods and feed, posing health risks to both humans and animals. However, the mechanism by which CTN damages the intestine remains unclear. In this study, a model of intestinal injury was induced by administering 1.25 mg/kg and 5 mg/kg of CTN via gavage for 28 consecutive days in 6-week-old Kunming mice, aiming to explore the potential mechanisms underlying intestinal injury. The results demonstrate that CTN can cause structural damage to the mouse jejunum. Additionally, CTN reduces the protein expression of Claudin-1, Occludin, ZO-1, and MUC2, thereby disrupting the physical and chemical barriers of the intestine. Furthermore, exposure to CTN alters the structure of the intestinal microbiota in mice, thus compromising the intestinal microbial barrier. Meanwhile, the results showed that CTN exposure could induce excessive apoptosis in intestinal cells by altering the expression of proteins such as CHOP and GRP78 in the endoplasmic reticulum and Bax and Cyt c in mitochondria. The mitochondria and endoplasmic reticulum are connected through the mitochondria-associated endoplasmic reticulum membrane (MAM), which regulates the membrane. We found that the expression of bridging proteins Fis1 and BAP31 on the membrane was increased after CTN treatment, which would exacerbate the endoplasmic reticulum dysfunction, and could activate proteins such as Caspase-8 and Bid, thus further inducing apoptosis via the mitochondrial pathway. Taken together, these results suggest that CTN exposure can cause intestinal damage by disrupting the intestinal barrier and inducing excessive apoptosis in intestinal cells.

D-Aspartic Acid (D-Asp) affects spermatogenesis by enhancing the biosynthesis of the sex steroid hormones acting either through the hypothalamus-pituitary-testis axis or directly on Leydig cells. Recently, in vitro studies have also demonstrated the direct effects of D-Asp on the proliferation and/or activity of germ cells. However, although D-Asp is present in Sertoli cells (SC), the specific role of the amino acid in these cells remains unknown. This study investigated the effects of D-Asp on the proliferation and activity of TM4 SC, focusing on the mitochondrial compartment and its association with the endoplasmic reticulum (ER). We found that D-Asp enhanced the proliferation and activity of TM4 cells as evidenced by the activation of ERK/Akt/PCNA pathway and the increase in the protein levels of the androgen receptor. Furthermore, D-Asp reduced both the oxidative stress and apoptotic process. An increase in mitochondrial functionality and dynamics, as well as a reduction in ER stress, were also found in D-Asp-treated TM4 cells. It is known that mitochondria are closely associated with ER to form the Mitochondrial-Associated Endoplasmic Reticulum Membranes (MAM), the site of calcium ions and lipid transfer from ER to the mitochondria, and vice versa. The data demonstrated that D-Asp induced stabilization of MAM in TM4 cells. In conclusion, this study is the first to demonstrate a direct effect of D-Asp on SC activity and to clarify the cellular/molecular mechanism underlying these effects, suggesting that D-Asp could stimulate spermatogenesis by improving the efficiency of SC.

Terbuthylazine (TBA) is a common triazine herbicide used in agricultural production, which causes toxic damage in multiple tissues. Hesperidin (HSP) is a flavonoid derivative that has anti-inflammatory, antioxidant and cytoprotective effects, but its role in reducing toxic damage caused by pesticides is still unclear. In this study, we aimed to investigate the toxic effect of TBA exposure on chicken hepatocytes and the therapeutic effect of HSP on the TBA-induced hepatotoxicity. Our results demonstrated that HSP could alleviate TBA exposure-induced endoplasmic reticulum (ER) stress. Interestingly, TBA significantly disrupted the integrity of mitochondria-associated endoplasmic reticulum membrane (MAM), while HSP treatment showed the opposite tendency. In addition, TBA could significantly trigger ferroptosis in liver, and HSP treatment reversed ferroptosis under TBA exposure. These results suggested that HSP could inhibit ER stress and alleviate ferroptosis under TBA exposure via maintaining MAM integrity, which provided a novel strategy to take precautions against TBA toxicity.

BACKGROUND: Type 2 diabetes (T2D) is a frequent comorbidity encountered in patients with severe aortic stenosis (AS), leading to an adverse left ventricular (LV) remodeling and dysfunction. Metabolic alterations have been suggested as contributors of the deleterious effect of T2D on LV remodeling and function in patients with severe AS, but so far, the underlying mechanisms remain unclear. Mitochondria play a central role in the regulation of cardiac energy metabolism.
OBJECTIVE: We aimed to explore the mitochondrial alterations associated with the deleterious effect of T2D on LV remodeling and function in patients with AS, preserved ejection fraction, and no additional heart disease.
METHODS: We combined an in-depth clinical, biological and echocardiography phenotype of patients with severe AS, with (n = 34) or without (n = 50) T2D, referred for a valve replacement, with transcriptomic and histological analyses of an intra-operative myocardial LV biopsy.
RESULTS: T2D patients had similar AS severity but displayed worse cardiac remodeling, systolic and diastolic function than non-diabetics. RNAseq analysis identified 1029 significantly differentially expressed genes. Functional enrichment analysis revealed several T2D-specific upregulated pathways despite comorbidity adjustment, gathering regulation of inflammation, extracellular matrix organization, endothelial function/angiogenesis, and adaptation to cardiac hypertrophy. Downregulated gene sets independently associated with T2D were related to mitochondrial respiratory chain organization/function and mitochondrial organization. Generation of causal networks suggested a reduced Ca2+ signaling up to the mitochondria, with the measured gene remodeling of the mitochondrial Ca2+ uniporter in favor of enhanced uptake. Histological analyses supported a greater cardiomyocyte hypertrophy and a decreased proximity between the mitochondrial VDAC porin and the reticular IP3-receptor in T2D.
CONCLUSIONS: Our data support a crucial role for mitochondrial Ca2+ signaling in T2D-induced cardiac dysfunction in severe AS patients, from a structural reticulum-mitochondria Ca2+ uncoupling to a mitochondrial gene remodeling. Thus, our findings open a new therapeutic avenue to be tested in animal models and further human cardiac biopsies in order to propose new treatments for T2D patients suffering from AS.
BACKGROUND: URL: https://www.
RESULTS: gov ; Unique Identifier: NCT01862237.

Amyotrophic lateral sclerosis (ALS) is the most prevalent motor neuron disease in adults. Currently, there are no known drugs or clinical approaches that have demonstrated efficacy in treating ALS. Mitochondrial function and autophagy have been identified as crucial mechanisms in the development of ALS. While Bax inhibitor 1 (BI1) has been implicated in neurodegenerative diseases, its exact mechanism remains unknown. This study investigates the therapeutic impact of BI1 overexpression on ALS both in vivo and in vitro, revealing its ability to mitigate SOD1G93A-induced apoptosis, nuclear damage, mitochondrial dysfunction, and axonal degeneration of motor neurons. At the same time, BI1 prolongs onset time and lifespan of ALS mice, improves motor function, and alleviates neuronal damage, muscle damage, neuromuscular junction damage among other aspects. The findings indicate that BI1 can inhibit pathological TDP43 morphology and initially stimulate autophagy through interaction with TDP43. This study establishes a solid theoretical foundation for understanding the regulation of autophagy by BI1 and TDP43 while shedding light on the pathogenesis of ALS through their interaction - offering new concepts and targets for clinical implementation and drug development.

Mitochondria are dynamic cellular organelles with complex roles in metabolism and signalling. Primary mitochondrial disorders are a group of approximately 400 monogenic disorders arising from pathogenic genetic variants impacting mitochondrial structure, ultrastructure and/or function. Amongst these disorders, defects of complex lipid biosynthesis, especially of the unique mitochondrial membrane lipid cardiolipin, and membrane biology are an emerging group characterised by clinical heterogeneity, but with recurrent features including cardiomyopathy, encephalopathy, neurodegeneration, neuropathy and 3-methylglutaconic aciduria. This review discusses lipid synthesis in the mitochondrial membrane, the mitochondrial contact site and cristae organising system (MICOS), mitochondrial dynamics and trafficking, and the disorders associated with defects of each of these processes. We highlight overlapping functions of proteins involved in lipid biosynthesis and protein import into the mitochondria, pointing to an overarching coordination and synchronisation of mitochondrial functions. This review also focuses on membrane interactions between mitochondria and other organelles, namely the endoplasmic reticulum, peroxisomes, lysosomes and lipid droplets. We signpost disorders of these membrane interactions that may explain the observation of secondary mitochondrial dysfunction in heterogeneous pathological processes. Disruption of these organellar interactions ultimately impairs cellular homeostasis and organismal health, highlighting the central role of mitochondria in human health and disease.

Over the past few years, the implementation of mass spectrometry (MS) in QC laboratories has become a more common occurrence. The multi-attribute method (MAM), and emerging intact multi-attribute method (iMAM), are powerful analytical tools utilising liquid chromatography-mass spectrometry (LC-MS) methods that enable the monitoring of critical quality attributes (CQAs) in biotherapeutic proteins in compliant settings. Both MAM and iMAM are intended to replace or supplement several conventional assays with a single LC-MS method utilising MS data in combination with robust, semi-automated data processing workflows. MAM and iMAM workflows can also be implemented into current Good Manufacturing Practices environments due to the availability of CFR 11 compliant chromatography data system software. In this study, MAM and iMAM are employed for the analysis of 4 batches of a glucagon-like peptide-Fc fusion protein. MAM approach involved a first the discovery phase for the identification of CQAs and second, the target monitoring phase of the selected CQAs in other samples. New peak detection was performed on the data set to determine the appearance, absence or change of any peak. For native iMAM workflow both size exclusion and strong cation exchange chromatography were optimized for the identification and monitoring of CQAs at the intact level.

Metabolic dysfunction is a hallmark of multiple amyotrophic lateral sclerosis (ALS) models with a majority of ALS patients exhibiting hypermetabolism. The central sites of metabolism in the cell are mitochondria, capable of utilising a multitude of cellular substrates in an array of ATP-generating reactions. With reactive oxygen species (ROS) production occurring during some of these reactions, mitochondria can contribute considerably to oxidative stress. Mitochondria are also very dynamic organelles, interacting with other organelles, undergoing fusion/fission in response to changing metabolic states and being turned over by the cell regularly. Disruptions to many of these mitochondrial functions and processes have been reported in ALS models, largely indicating compromised mitochondrial function, increased ROS production by mitochondria, disrupted interactions with the endoplasmic reticulum and reduced turnover. This chapter summarises methods routinely used to assess mitochondria in ALS models and the alterations that have been reported in these models.

Over the past two decades, we have witnessed a growing appreciation for the importance of membrane contact sites (CS) in facilitating direct communication between organelles. CS are tiny regions where the membranes of two organelles meet but do not fuse and allow the transfer of metabolites between organelles, playing crucial roles in the coordination of cellular metabolic activities. The significant advancements in imaging techniques and molecular and cell biology research have revealed that CS are more complex than what originally thought, and as they are extremely dynamic, they can remodel their shape, composition, and functions in accordance with metabolic and environmental changes and can occur between more than two organelles. Here, we describe how recent studies led to the identification of a three-way mitochondria-ER-lipid droplet CS and discuss the emerging functions of these contacts in maintaining lipid storage, homeostasis, and balance. We also summarize the properties and functions of key protein components localized at the mitochondria-ER-lipid droplet interface, with a special focus on lipid transfer proteins. Understanding tripartite CS is essential for unraveling the complexities of inter-organelle communication and cooperation within cells.

Repeated sevoflurane exposure in neonatal mice can leads to neuronal apoptosis and mitochondrial dysfunction. The mitochondria are responsible for energy production to maintain homeostasis in the central nervous system. The mitochondria-associated endoplasmic reticulum membrane (MAM) is located between the mitochondria and endoplasmic reticulum (ER), and it is critical for mitochondrial function and cell survival. MAM malfunction contributes to neurodegeneration, however, whether it is involved in sevoflurane-induced neurotoxicity remains unknown. Our study demonstrated that repeated sevoflurane exposure induced mitochondrial dysfunction and dampened the MAM structure. The upregulated ER-mitochondria tethering enhanced Ca2+ transition from the cytosol to the mitochondria. Overload of mitochondrial Ca2+ contributed to opening of the mitochondrial permeability transition pore (mPTP), which caused neuronal apoptosis. Mitofusin 2(Mfn2), a key regulator of ER-mitochondria contacts, was found to be suppressed after repeated sevoflurane exposure, while restoration of Mfn2 expression alleviated cognitive dysfunction due to repeated sevoflurane exposure in the adult mice. These evidences suggest that sevoflurane-induced MAM malfunction is vulnerable to Mfn2 suppression, and the enhanced ER-mitochondria contacts promotes mitochondrial Ca2+ overload, contributing to mPTP opening and neuronal apoptosis. This paper sheds light on a novel mechanism of sevoflurane-induced neurotoxicity. Furthermore, targeting Mfn2-mediated regulation of the MAM structure and mitochondrial function may provide a therapeutic advantage in sevoflurane-induced neurodegeneration.