Mitochondrial Dynamics Research Articles

Laherradurin Inhibits Colorectal Cancer Cell Growth by Induction of Mitochondrial Dysfunction and Autophagy Induction.

CRC cells were treated with LAH, and its effects on mitochondrial respiration and glycolysis were measured using Seahorse XF technology. The changes in mitochondrial dynamics were observed through fluorescent imaging, while Western blot analysis was used to examine key autophagy and apoptosis markers. LAH significantly inhibited mitochondrial complex I activity, inducing ATP depletion and a compensatory increase in glycolysis. This disruption caused mitochondrial fragmentation, a trigger for autophagy, as shown by increased LC3-II expression and mTOR suppression. Apoptosis was also confirmed through the cleavage of caspase-3, contributing to reduced cancer cell viability. LAH's anticancer effects in CRC cells are driven by its disruption of mitochondrial function, triggering both autophagy and apoptosis. These findings highlight its potential as a therapeutic compound for further exploration in cancer treatment.

HLA-G neo-expression modifies genetic programs governing tumor cell lines

The development of immunotherapies has proved to be clinically encouraging to re-establish the immune function modified by the expression of immune inhibitory molecules in tumors. However, there are still patients with poor survival rates following treatment. The elucidation of molecular mechanisms triggered by the neo-expression of particular IC in tumors would constitute a major step toward better understanding tumor evolution and would help to design future clinical protocols. To this end, we investigate the modifications triggered by the neo-expression of the immune checkpoints HLA-G in ccRCC tumor cells. We demonstrate, for the first time, that HLA-G modifies key genes implicated mainly in tumor development, angiogenesis, calcium flow and mitochondria dynamics. The involvement of HLA-G on the expression of genes belonging to these pathways such as ADAM-12, NCAM1 and NRP1 was confirmed by the CRISPR/Cas9-mediated edition of HLA-G. The data reveal multifaceted roles of HLA-G in tumor cells which are far beyond the well-known function of HLA-G in the immune anti-tumor response. This warrants further investigation of HLA-G and these new partners in tumors of different origin so as to propose future new treatments to improve health patient’s outcome.

Calorie restriction modulates mitochondrial dynamics and autophagy in leukocytes of patients with obesity

Although it is established that caloric restriction offers metabolic and clinical benefits, the molecular mechanisms underlying these effects remain unclear. Thus, this study aimed to investigate whether caloric restriction can modulate mitochondrial function and remodelling and stimulate autophagic flux in the PBMCs of patients with obesity. This was an interventional study of 38 obese subjects (BMI > 35 kg/m2) who underwent 6 months of dietary therapy, including a 6-week very-low-calorie diet (VLCD) followed by an 18-week low-calorie diet (LCD). We determined clinical variables, mitochondrial function parameters (by fluorescence imaging of mitochondrial ROS and membrane potential), and protein expression of markers of mitochondrial dynamics (MNF1, MFN2, OPA, DRP1 and FIS1) and autophagy (LC3, Beclin, BCL2 and NBR1) by western blot. Caloric restriction induced an improvement in metabolic outcomes that was accompanied by an increase in AMPK expression, a decrease of mitochondrial ROS and mitochondrial membrane potential, which was associated with increased markers of mitochondrial dynamics (MFN2, DRP1 and FIS1) and activation of autophagy as evidenced by augmented LC3 II/I, Beclin1 and NBR1, and a decrease in BCL2. These findings shed light on the specific molecular mechanisms by which caloric restriction facilitates metabolic improvements, highlighting the relevance of pathways involving energy homeostasis and cell recovery, including mitochondrial function and dynamics and autophagy.

Mitochondrial dynamics and energy metabolism interference therapy for promoting photothermal sensitization

Photothermal therapy (PTT) is minimally invasive, precisely controlled, and therapeutically effective treatment method. However, its efficacy is limited by the overexpression of heat shock proteins (HSP), which leads to cellular thermal blockade. Targeting mitochondria with PTT can enhance anticancer efficacy, as mitochondria encode genes related to HSP and provide energy for their production. Nevertheless, mitochondrial dynamics confer resistance to damage from external stimuli. Therefore, disrupting the balance of mitochondrial dynamics is essential to impede HSP production. Herein, we synthesized degradable Cu3BiS3 (CBS) nanosheets (NSs) with one face modified by carboxylated triphenylphosphonium (TPP) to target mitochondria. This modification increases the production of exogenous reactive oxygen species (ROS) and induces the overexpression of dynamin-related protein 1 (Drp1), disrupting mitochondrial dynamic homeostasis. The other face was modified with carboxylated β-cyclodextrin (CD) to load the glycolysis inhibitor (2-deoxyglucose, 2DG), thereby reducing adenosine triphosphate (ATP) production in the extra-mitochondrial space, as glycolysis also occurs in the cytoplasm. The resulting TPP-CBS-2DG Janus NSs (JNSs) not only disrupt mitochondrial energy production, leading to cell starvation, but also inhibit HSP production. Consequently, TPP-CBS-2DG JNSs can enhance tumor thermal sensitivity in PTT, improving its efficacy. This work holds great promise for overcoming tumor heat resistance in PTT and provides a feasible method for fabricating selectively modified multifunctional NSs.

CHK1 attenuates cardiac dysfunction via suppressing SIRT1-ubiquitination

BackgroundMitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation, however, its role on mitochondrial function in I/R injury remains unknown. MethodsTo investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/overexpression mouse models were generated. Adult mouse cardiomyocytes (AMCMs) were isolated for in vitro study. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism. ResultsCHK1 was downregulated in myocardium post I/R and AMCMs post oxygen-glucose deprivation/re‑oxygenation (OGD/R). In vivo, CHK1 overexpression protected against I/R induced cardiac dysfunction, while heterogenous CHK1 knockout exacerbated cardiomyopathy. In vitro, CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266–390 domain of CHK1 interacted with the 160–583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. The role of CHK1 in maintaining mitochondrial dynamics control and myocardial protection is abolished by SIRT1 inhibition, while inactivated mutation of SIRT1 Thr530 fails to reverse the impaired mitochondrial dynamics following CHK1 knockdown. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown attenuated the protective role of CHK1 in I/R injury. ConclusionsOur findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.

Astrocytic lactoferrin deficiency augments MPTP-induced dopaminergic neuron loss by disturbing glutamate/calcium and ER-mitochondria signaling

Increased levels of lactoferrin (Lf) are present in the aged brain and in the lesions of various neurodegenerative diseases, including Parkinson's disease (PD), and may contribute to the cascade of events involved in neurodevelopment and neuroprotection. However, whether Lf originates from astrocytes and functions within either the normal or pathological brain are unknown. Here, we employed mice with specific knockout of the astrocyte lactoferrin gene (named Lf-cKO) to explore its specific roles in the pathological process of PD. We observed a decrease in tyrosine hydroxylase-positive cells, mitochondrial dysfunction of residual dopaminergic neurons, and motor deficits in Lf-cKO mice, which were significantly aggravated after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment. To further explore how astrocytic lactoferrin deficiency exacerbated PD-like manifestation in MPTP-treated mice, the critical molecules involved in endoplasmic reticulum (ER)-mitochondria contacts and signaling pathways were investigated. In vitro and in vivo models, we found an aberrant level of effects implicated in glutamate and calcium homeostasis, mitochondrial morphology and functions, mitochondrial dynamics, and mitochondria-associated ER membranes, accompanied by signs of oxidative stress and ER stress, which increase the fragility of dopaminergic neurons. These findings confirm the existence of astrocytic Lf and its influence on the fate of dopaminergic neurons by regulating glutamate/calcium metabolism and ER-mitochondria signaling. Our findings may be a promising target for the treatment of PD.

NIPSNAP3A regulates cellular homeostasis by modulating mitochondrial dynamics

Mitochondria are essential for cell metabolism and survival as they produce the majority of cellular ATP through oxidative phosphorylation as well as regulate critical processes such as cell proliferation and apoptosis. NIPSNAP family of proteins are predominantly mitochondrial matrix proteins. However, the molecular and cellular functions of the NIPSNAPs, particularly NIPSNAP3A, have remained elusive. Here, we demonstrated that NIPSNAP3A knockdown in HeLa cells inhibited their proliferation and migration and attenuated apoptosis induced by Actinomycin D (Act-D). These findings suggested a complex relationship between cellular processes and mitochondrial functions, mediated by NIPSNAP3A. Further investigations revealed that NIPSNAP3A knockdown not only inhibited mitochondrial fission through reduction of DRP1-S616, but also suppressed cytochrome c release in apoptosis. Collectively, our findings highlight the critical role of NIPSNAP3A in coordinating cellular processes, likely through its influence on mitochondrial dynamics.

Hypoxia-induced mitochondrial fission regulates the fate of bone marrow mesenchymal stem cells by maintaining HIF1α stabilization

For mesenchymal stem cells derived from bone marrow, a controlled reduction in ambient oxygen concentration has been recognized as a facilitator of osteogenic differentiation and the formation of calcium nodules. However, the specific molecular mechanisms underlying this phenotype remain unclear. The aim of this study was to elucidate the impact of hypoxia on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and to explore the involvement of mitophagy and the regulation of mitochondrial dynamics mediated by the mitochondrial dynamic regulatory factor FUN14 domain-containing 1 (FUNDC1). Our findings suggest that FUNDC1 is required for promoting osteogenic differentiation in BMSCs under hypoxic conditions. However, this effect was not dependent on FUNDC1-mediated mitophagy but rather on FUNDC1-mediated regulation of mitochondrial fission. At the mechanistic level, FUNDC1 binds more DNM1L and less OPA1 under hypoxic conditions, leading to an upsurge in mitochondrial division. This heightened mitochondrial division culminates in the increased translocation of Parkin to mitochondria, diminishing its interactions with HIF1α in the cytoplasm and consequently facilitating HIF1α deubiquitination and stabilization. In summary, FUNDC1-regulated mitochondrial division in hypoxic culture emerges as a critical determinant for the translocation of Parkin to mitochondria, ultimately maintaining HIF1α stabilization and promoting osteogenic differentiation.

Leveraging metabolism for better outcomes in heart failure.

Whilst metabolic inflexibility and substrate constraint have been observed in heart failure for many years, their exact causal role remains controversial. In parallel, many of our fundamental assumptions about cardiac fuel use are now being challenged like never before. For example, the emergence of sodium glucose cotransporter 2 inhibitor (SGLT2i) therapy as one of the four "pillars" of heart failure therapy is causing a revisit of metabolism as a key mechanism and therapeutic target in heart failure. Improvements in the field of cardiac metabolomics will lead to a far more granular understanding of the mechanisms underpinning normal and abnormal human cardiac fuel use, an appreciation of drug action, and novel therapeutic strategies. Technological advances and expanding biorepositories offer exciting opportunities to elucidate the novel aspects of these metabolic mechanisms. Methodologic advances include comprehensive and accurate substrate quantitation such as metabolomics and stable-isotope fluxomics, improved access to arterio-venous blood samples across the heart to determine fuel consumption and energy conversion, high quality cardiac tissue biopsies, biochemical analytics, and informatics. Pairing these technologies with recent discoveries in epigenetic regulation, mitochondrial dynamics, and organ-microbiome metabolic crosstalk will garner critical mechanistic insights in heart failure. In this state-of-the-art review, we focus on new metabolic insights, with an eye on emerging metabolic strategies for heart failure. Our synthesis of the field will be valuable for a diverse audience with an interest in cardiac metabolism.

The tolerable upper intake level of manganese alleviates Parkinson-like motor performance and neuronal loss by activating mitophagy

Manganese (Mn2+) is among the indispensable trace elements required by the human body, but high-dose Mn2+ exposure can lead to Mn poisoning. Therefore, the tolerable upper intake level (UL) for Mn2+ has been established for normal individuals in different countries. However, whether the UL of Mn2+ is suitable for the patients of Parkinson's disease (PD) is unclear.Here, we found unexpectedly that the dietary UL of Mn2+ supplement enhanced mitophagy through the PINK1/parkin-mediated ubiquitin-dependent pathway in MPTP- induced mice and cells. Mn2+ promoted mitochondrial biogenesis and dynamics, thereby increased the activity of the mitochondrial respiratory chain with restored mitochondrial function. Additionally, Mn2+ directly elevated the activity of mitochondrial superoxide dismutase (MnSOD), which contributed to the clearance of reactive oxygen species (ROS), restored dopaminergic and motor functions in the MPTP-induced PD mouse model. Similar results were also observed in SH-SY5Y cells, whereas knockdown parkin using siRNA or application of mitophagy inhibitors (Mdivi-1 or cyclosporine A), abolished the neuroprotective effects of Mn2+.These findings demonstrate that the dietary UL of Mn2+ is protective for the MPTP-induced Parkinson-like lesions with the mechanisms involving the activation of mitophagy, suggesting potential intervention of PD by moderately increasing dietary Mn2+ intake.

Accelerated mitochondrial dynamics promote spermatogonial differentiation

At different stages of spermatogenesis, germ cell mitochondria differ remarkably in morphology, architecture, and functions. However, it remains elusive how mitochondria change their features during spermatogonial differentiation, which in turn impacts spermatogonial stem cell fate decision. In this study, we observed that mitochondrial fusion and fission were both upregulated during spermatogonial differentiation. As a result, the mitochondrial morphology remained unaltered. Enhanced mitochondrial fusion and fission promoted spermatogonial differentiation, while the deficiency in DRP1-mediated fission led to a stage-specific blockage of spermatogenesis at differentiating spermatogonia. Our data further revealed that increased expression of pro-fusion factor MFN1 upregulated mitochondrial metabolism, whereas DRP1 specifically regulated mitochondrial permeability transition pore opening in differentiating spermatogonia. Taken together, our findings unveil how proper spermatogonial differentiation is precisely controlled by concurrently accelerated and properly balanced mitochondrial fusion and fission in a germ cell stage-specific manner, thereby providing critical insights about mitochondrial contribution to stem cell fate decision.

Targeting Mitochondria: Influence of Metabolites on Mitochondrial Heterogeneity.

Mitochondria are vital organelles that provide energy for the metabolic processes of cells. These include regulating cellular metabolism, autophagy, apoptosis, calcium ions, and signaling processes. Despite their varying functions, mitochondria are considered semi-independent organelles that possess their own genome, known as mtDNA, which encodes 13 proteins crucial for oxidative phosphorylation. However, their diversity reflects an organism's adaptation to physiological conditions and plays a complex function in cellular metabolism. Mitochondrial heterogeneity exists at the single-cell and tissue levels, impacting cell shape, size, membrane potential, and function. This heterogeneity can contribute to the progression of diseases such as neurodegenerative diseases, metabolic diseases, and cancer. Mitochondrial dynamics enhance the stability of cells and sufficient energy requirement, but these activities are not universal and can lead to uneven mitochondria, resulting in heterogeneity. Factors such as genetics, environmental compounds, and signaling pathways are found to affect these cellular processes and heterogeneity. Additionally, the varying roles of metabolites such as NADH and ATP affect glycolysis's speed and efficiency. An imbalance in metabolites can impair ATP production and redox potential in the mitochondria. Therefore, this review will explore the influence of metabolites in shaping mitochondrial morphology, how these changes contribute to age-related diseases and the therapeutic targets for regulating mitochondrial heterogeneity.

Molybdenum nanodots act as antioxidants for photothermal therapy osteoarthritis

Osteoarthritis (OA) manifests as the degradation of cartilage and remodeling of subchondral bone. Restoring homeostasis within the joint is imperative for alleviating OA symptoms. Current interventions primarily target singular aspects, such as anti-aging, inflammation inhibition, free radical scavenging, and regeneration of cartilage and subchondral bone. Herein, we developed molybdenum nanodots (MNDs) as bionic photothermal nanomaterials to mimic the antioxidant synthase to concurrently protected cartilage and facilitate subchondral bone regeneration. With near-infrared (NIR) irradiation, MNDs effectively eliminate reactive oxygen and nitrogen species (ROS/RNS) from OA chondrocytes, thereby reversed mitochondrial dysfunction, mitigating chondrocyte senescence, and simultaneously suppresses inflammation, hence preserving the inherent homeostasis between cartilage matrix synthesis and degradation while circumventing safety concerns. RNA sequencing of OA chondrocytes treated with MNDs-NIR revealed the reinstatement of chondrocyte functionality, activation of antioxidant enzymes, anti-aging properties, and regulation of inflammation. NIR irradiation induces thermogenesis and synergistically promotes subchondral bone regeneration via MNDs, as validated through histological assessments and microcomputed tomography (Micro-CT) scans. MNDs-NIR effectively attenuate cellular senescence and inhibit inflammation in vivo, while also remodeling mitochondrial dynamics by upregulating fusion proteins and inhibiting fission proteins, thereby regulating the oxidative stress microenvironment. Additionally, MNDs-NIR exhibited remarkable therapeutic effects in alleviating articular cartilage degeneration in an OA mouse model, evidenced by a 1.67-fold reduction in subchondral bone plate thickness, an 88.57% decrease in OARSI score, a 5.52-fold reduction in MMP13 expression, and a 6.80-fold increase in Col II expression. This novel disease-modifying approach for OA utilizing MNDs-NIR offers insight and a paradigm for improving mitochondrial dysfunction by regulating the accumulation of mitochondrial ROS and ultimately alleviating cellular senescence. Moreover, the dual-pronged therapeutic approach of MNDs-NIR, which addresses both cartilage erosion and subchondral bone lesions in OA, represents a highly promising strategy for managing OA.

Reciprocal regulation of oxidative stress and mitochondrial fission augments parvalbumin downregulation through CDK5-DRP1- and GPx1-NF-κB signaling pathways

Loss of parvalbumin (PV) expressing neurons (PV neurons) is relevant to the underlying mechanisms of the pathogenesis of neurological and psychiatric diseases associated with the dysregulation of neuronal excitatory networks and brain metabolism. Although PV modulates mitochondrial morphology, volume and dynamics, it is largely unknown whether mitochondrial dynamics affect PV expression and what the molecular events are responsible for PV neuronal degeneration. In the present study, L-buthionine sulfoximine (BSO, an inhibitor of glutathione synthesis) did not degenerate PV neurons under physiological condition. However, BSO-induced oxidative stress decreased PV expression and facilitated cyclin-dependent kinase 5 (CDK5) tyrosine (Y) 15 phosphorylation, dynamin-related protein 1 (DRP1)-mediated mitochondrial fission and glutathione peroxidase-1 (GPx1) downregulation in PV neurons. Co-treatment of roscovitine (a CDK5 inhibitor) or mitochondrial division inhibitor-1 (Mdivi-1, an inhibitor of mitochondrial fission) attenuated BSO-induced PV downregulation. WY14643 (an inducer of mitochondrial fission) reduced PV expression without affecting CDK5 Y15 phosphorylation. Following status epilepticus (SE), CDK5 Y15 phosphorylation and mitochondrial fission were augmented in PV neurons. These were accompanied by reduced GPx1-mediated inhibition of NF-κB p65 serine (S) 536 phosphorylation. N-acetylcysteine (NAC), roscovitine and Mdivi-1 ameliorated SE-induced PV neuronal degeneration by mitigating CDK5 Y15 hyperphosphorylation, aberrant mitochondrial fragmentation and reduced GPx1-mediated NF-κB inhibition. Furthermore, SN50 (a NF-κB inhibitor) alleviated SE-induced PV neuronal degeneration, independent of dysregulation of mitochondrial fission, CDK5 hyperactivation and GPx1 downregulation. These findings provide an evidence that oxidative stress may activate CDK5-DRP1- and GPx1-NF-κB-mediated signaling pathways, which would be possible therapeutic targets for preservation of PV neurons in various diseases.

Spinster homolog 2/S1P signaling ameliorates macrophage inflammatory response to bacterial infections by balancing PGE2 production

BackgroundMitochondria play a crucial role in shaping the macrophage inflammatory response during bacterial infections. Spinster homolog 2 (Spns2), responsible for sphingosine-1-phosphate (S1P) secretion, acts as a key regulator of mitochondrial dynamics in macrophages. However, the link between Spns2/S1P signaling and mitochondrial functions remains unclear.MethodsPeritoneal macrophages were isolated from both wild-type and Spns2 knockout rats, followed by non-targeted metabolomics and RNA sequencing analysis to identify the potential mediators through which Spns2/S1P signaling influences the mitochondrial functions in macrophages. Various agonists and antagonists were used to modulate the activation of Spns2/S1P signaling and its downstream pathways, with the underlying mechanisms elucidated through western blotting. Mitochondrial functions were assessed using flow cytometry and oxygen consumption assays, as well as morphological analysis. The impact on inflammatory response was validated through both in vitro and in vivo sepsis models, with the specific role of macrophage-expressed Spns2 in sepsis evaluated using Spns2flox/floxLyz2-Cre mice. Additionally, the regulation of mitochondrial functions by Spns2/S1P signaling was confirmed using THP-1 cells, a human monocyte-derived macrophage model.ResultsIn this study, we unveil prostaglandin E2 (PGE2) as a pivotal mediator involved in Spns2/S1P-mitochondrial communication. Spns2/S1P signaling suppresses PGE2 production to support malate-aspartate shuttle activity. Conversely, excessive PGE2 resulting from Spns2 deficiency impairs mitochondrial respiration, leading to intracellular lactate accumulation and increased reactive oxygen species (ROS) generation through E-type prostanoid receptor 4 activation. The overactive lactate-ROS axis contributes to the early-phase hyperinflammation during infections. Prolonged exposure to elevated PGE2 due to Spns2 deficiency culminates in subsequent immunosuppression, underscoring the dual roles of PGE2 in inflammation throughout infections. The regulation of PGE2 production by Spns2/S1P signaling appears to depend on the coordinated activation of multiple S1P receptors rather than any single one.ConclusionsThese findings emphasize PGE2 as a key effector of Spns2/S1P signaling on mitochondrial dynamics in macrophages, elucidating the mechanisms through which Spns2/S1P signaling balances both early hyperinflammation and subsequent immunosuppression during bacterial infections.

Comparative evaluation of cigarette smoke and a heated tobacco product on microglial toxicity, oxidative stress and inflammatory response

BackgroundTobacco smoking is the leading cause of preventable death and disease worldwide, with over 8 million annual deaths attributed to cigarette smoking. This study investigates the impact of cigarette smoke and heated tobacco products (HTPs) on microglial function, focusing on toxicological profiles, inflammatory responses, and oxidative stress using ISO standard and clinically relevant conditions of exposure.MethodsWe assessed cell viability, reactive oxygen species (ROS) production, lipid peroxidation, mitochondrial function, unfolded protein response, and inflammation in human microglial cells (HMC3) exposed to cigarette smoke, HTP aerosol or nicotine.ResultsOur findings show that cigarette smoke significantly reduces microglial viability, increases ROS formation, induces lipid peroxidation, and reduces intracellular glutathione levels. Cigarette smoke also alters the expression of genes involved in mitochondrial dynamics and biogenesis, leading to mitochondrial dysfunction. Additionally, cigarette smoke impairs the unfolded protein response, activates the NF-κB pathway, and induces a pro-inflammatory state characterized by increased TNF and IL-18 expression. Furthermore, cigarette smoke causes DNA damage and decreases the expression of the aging marker Klotho β. In contrast, HTP, exhibited a lesser degree of microglial toxicity, with reduced ROS production, lipid peroxidation, and mitochondrial dysfunction compared to conventional cigarettes.ConclusionThese results highlight the differential toxicological profile of cigarette smoke and HTP on microglial cells, suggesting a potential harm reduction strategy for neurodegenerative disease for smokers unwilling or unable to quit.

Enhanced mitochondrial fluorescence imaging through confinement fluorescence effect within a rigid silicon suboxide network

Fluorescence imaging technology has emerged as a powerful tool for studying intricate mitochondrial morphology within living cells. However, the need for fluorophores with stable fluorescence intensity and low phototoxicity poses significant challenges, particularly for long-term live-cell mitochondrial monitoring. To address this, we introduce the confinement fluorescence effect (CFE) into the design of fluorophores. This strategy involves confining small-molecule fluorophores within a silicon suboxide network structure of nanoparticles (CEF-NPs), which restricts molecular rotation, resulting in the suppression of non-radiative transition and the isolation of encapsulated fluorophores from surrounding quenching factors. CFE-NPs (SY2@SiOx) exhibit exceptional properties, such as high fluorescence intensity (80-fold) and reduced phototoxicity (0.15-fold). Furthermore, the TPP + -functionalized CFE-NPs (SY2@SiOxTPP) demonstrated efficacy in mitochondrial imaging and mitochondrial dynamics monitoring. Biochemistry assays indicated that SY2@SiOxTPP exhibits significantly lower phototoxicity to mitochondrial functions compared to both small-molecule fluorophore and commercial Mito Tracker. This approach allows for the long-term dynamic monitoring of mitochondrial morphological changes through fluorescence imaging, without impairing mitochondrial functionality.

AIBP controls TLR4 inflammarafts and mitochondrial dysfunction in a mouse model of Alzheimer’s disease

Microglia-driven neuroinflammation plays an important role in the development of Alzheimer’s disease. Microglia activation is accompanied by the formation and chronic expression of TLR4 inflammarafts, defined as enlarged and cholesterol-rich lipid rafts serving as an assembly platform for TLR4 dimers and complexes of other inflammatory receptors. The secreted apoA-I binding protein (APOA1BP or AIBP) binds TLR4 and selectively targets cholesterol depletion machinery to TLR4 inflammaraft-expressing inflammatory, but not homeostatic microglia. Here we demonstrated that amyloid-beta (Aβ) induced formation of TLR4 inflammarafts in microglia in vitro and in the brain of APP/PS1 mice. Mitochondria in Apoa1bp−/− APP/PS1 microglia were hyperbranched and cupped, which was accompanied by increased reactive oxygen species and the dilated endoplasmic reticulum. The size and number of Aβ plaques and neuronal cell death were significantly increased, and the animal survival was decreased in Apoa1bp−/−APP/PS1 compared to APP/PS1 female mice. These results suggest that AIBP exerts control of TLR4 inflammarafts and mitochondrial dynamics in microglia and plays a protective role in Alzheimer’s disease associated oxidative stress and neurodegeneration.

QSOX2 Deficiency-induced short stature, gastrointestinal dysmotility and immune dysfunction.

Postnatal growth failure is often attributed to dysregulated somatotropin action, however marked genetic and phenotypic heterogeneity exist. We report five patients from three families who present with short stature, immune dysfunction, atopic eczema and gastrointestinal pathology associated with recessive variants in QSOX2. QSOX2 encodes a nuclear membrane protein linked to disulphide isomerase and oxidoreductase activity. Loss of QSOX2 disrupts Growth hormone-mediated STAT5B nuclear translocation despite enhanced Growth hormone-induced STAT5B phosphorylation. Moreover, patient-derived dermal fibroblasts demonstrate Growth hormone-induced mitochondriopathy and reduced mitochondrial membrane potential. Located at the nuclear membrane, QSOX2 acts as a gatekeeper for regulating stabilisation and import of phosphorylated-STAT5B. Altogether, QSOX2 deficiency modulates human growth by impairing Growth hormone-STAT5B downstream activities and mitochondrial dynamics, which contribute to multi-system dysfunction. Furthermore, our work suggests that therapeutic recombinant insulin-like growth factor-1 may circumvent the Growth hormone-STAT5B dysregulation induced by pathological QSOX2 variants and potentially alleviate organ specific disease.

Exploring Liraglutide in Lithium-Pilocarpine-Induced Temporal Lobe Epilepsy Model in Rats: Impact on Inflammation, Mitochondrial Function, and Behavior.

Background/Objectives: Glucagon-like peptide-1 receptor agonists such as liraglutide are known for their neuroprotective effects in neurodegenerative disorders, but their role in temporal lobe epilepsy (TLE) remains unclear. We aimed to investigate the effects of liraglutide on several biological processes, including inflammation, antioxidant defense mechanisms, mitochondrial dynamics, and function, as well as cognitive and behavioral changes in the TLE model. Methods: Low-dose, repeated intraperitoneal injections of lithium chloride-pilocarpine hydrochloride were used to induce status epilepticus (SE) in order to develop TLE in rats. Fifty-six male Sprague Dawley rats were subjected and allocated to the groups. The effects of liraglutide on inflammatory markers (NLRP3, Caspase-1, and IL-1β), antioxidant pathways (Nrf-2 and p-Nrf-2), and mitochondrial dynamics proteins (Pink1, Mfn2, and Drp1) were evaluated in hippocampal tissues via a Western blot. Mitochondrial function in peripheral blood mononuclear cells (PBMCs) was examined using flow cytometry. Cognitive-behavioral outcomes were assessed using the open-field, elevated plus maze, and Morris water maze tests. Results: Our results showed that liraglutide modulates NLRP3-mediated inflammation, reduces oxidative stress, and triggers antioxidative pathways through Nrf2 in SE-induced rats. Moreover, liraglutide treatment restored Pink1, Mfn2, and Drp1 levels in SE-induced rats. Liraglutide treatment also altered the mitochondrial function of PBMCs in both healthy and epileptic rats. This suggests that treatment can modulate mitochondrial dynamics and functions in the brain and periphery. Furthermore, in the behavioral aspect, liraglutide reversed the movement-enhancing effect of epilepsy. Conclusions: This research underscores the potential of GLP-1RAs as a possibly promising therapeutic strategy for TLE.