Dysfunction Of Mitochondrial Dynamics Research Articles

Does photobiomodulation alter mitochondrial dynamics?

Mitochondrial dysfunction is one of the leading causes of disease development. Dysfunctional mitochondria limit energy production, increase reactive oxygen species generation, and trigger apoptotic signals. Photobiomodulation is a noninvasive, nonthermal technique involving the application of monochromatic light with low energy density, inducing non-thermal photochemical effects at the cellular level, and it has been used due to its therapeutic potential. This review focuses on the mitochondrial dynamic's role in various diseases, evaluating the possible therapeutic role of low-power lasers (LPL) and light-emitting diodes (LED). Studies increasingly support that mitochondrial dysfunction is correlated with severe neurodegenerative diseases such as Parkinson's, Huntington's, Alzheimer's, and Charcot-Marie-Tooth diseases. Furthermore, a disturbance in mitofusin activity is also associated with metabolic disorders, including obesity and type 2 diabetes. The effects of PBM on mitochondrial dynamics have been observed in cells using a human fibroblast cell line and invivo models of brain injury, diabetes, spinal cord injury, Alzheimer's disease, and skin injury. Thus, new therapies aiming to improve mitochondrial dynamics are clinically relevant. Several studies have demonstrated that LPL and LED can be important therapies to improve health conditions when there is dysfunction in mitochondrial dynamics.

Dietary α-Ketoglutarate Alleviates Escherichia coli LPS-Induced Intestinal Barrier Injury by Modulating the Endoplasmic Reticulum-Mitochondrial System Pathway in Piglets

Backgroundα-Ketoglutarate (AKG) plays a pivotal role in mitigating inflammation and enhancing intestinal health. ObjectivesThis study aimed to investigate whether AKG could protect against lipopolysaccharide (LPS)-induced intestinal injury by alleviating disorders in mitochondria-associated endoplasmic reticulum (MAM) membranes, dysfunctional mitochondrial dynamics, and endoplasmic reticulum (ER) stress in a piglet model. MethodsTwenty-four piglets were subjected to a 2 × 2 factorial design with dietary factors (basal diet or 1% AKG diet) and LPS treatment (LPS or saline). After 21 d of consuming either the basal diet or AKG diet, piglets received injections of LPS or saline. The experiment was divided into 4 treatment groups [control (CON) group: basal diet + saline; LPS group: basal diet +LPS; AKG group: AKG diet + saline; and AKG_LPS group: AKG + LPS], each consisting of 6 piglets. ResultsThe results demonstrated that compared with the CON group, AKG enhanced jejunal morphology, antioxidant capacity, and the messenger RNA and protein expression of tight junction proteins. Moreover, it has shown a reduction in serum diamine oxidase activity and D-lactic acid content in piglets. In addition, fewer disorders in the ER-mitochondrial system were reflected by AKG, as evidenced by AKG regulating the expression of key molecules of mitochondrial dynamics (mitochondrial calcium uniporter, optic atrophy 1, fission 1, and dynamin-related protein 1), ER stress [activating transcription factor (ATF) 4, ATF 6, C/EBP homologous protein, eukaryotic initiation factor 2α, glucose-regulated protein (GRP) 78, and protein kinase R-like ER kinase], and MAM membranes [mitofusin (Mfn)-1, Mfn-2, GRP 75, and voltage-dependent anion channel-1]. ConclusionsDietary AKG can prevent mitochondrial dynamic dysfunction, ER stress, and MAM membrane disorder, ultimately alleviating LPS-induced intestinal damage in piglets.

PTEN-induced kinase 1 deficiency alters albumin permeability and insulin signaling in podocytes.

Alterations of insulin signaling in diabetes are associated with podocyte injury, proteinuria, and renal failure. Insulin stimulates glucose transport to cells and regulates other intracellular processes that are linked to cellular bioenergetics, such as autophagy, gluconeogenesis, fatty acid metabolism, and mitochondrial homeostasis. The dysfunction of mitochondrial dynamics, including mitochondrial fusion, fission, and mitophagy, has been observed in high glucose-treated podocytes and renal cells from patients with diabetes. Previous studies showed that prolonged hyperglycemia is associated with the development of insulin resistance in podocytes, and high glucose-treated podocytes exhibit an increase in mitochondrial fission and decrease in markers of mitophagy. In the present study, we found that deficiency of the main mitophagy protein PTEN-induced kinase 1 (PINK1) significantly increased albumin permeability and hampered glucose uptake to podocytes. We suggest that PINK1 inhibition impairs the insulin signaling pathway, in which lower levels of phosphorylated Akt and membrane fractions of the insulin receptor and glucose transporter-4 were observed. Moreover, PINK1-depleted podocytes exhibited lower podocin and nephrin expression, thus identifying a potential mechanism whereby albumin leakage increases under hyperglycemic conditions when mitophagy is inhibited. In conclusion, we found that PINK1 plays an essential role in insulin signaling and the maintenance of proper permeability in podocytes. Therefore, PINK1 may be a potential therapeutic target for the treatment or prevention of diabetic nephropathy.

Predicting Mitochondrial Dynamic Behavior in Genetically Defined Neurodegenerative Diseases.

Mitochondrial dynamics encompass mitochondrial fusion, fission, and movement. Mitochondrial fission and fusion are seemingly ubiquitous, whereas mitochondrial movement is especially important for organelle transport through neuronal axons. Here, we review the roles of different mitochondrial dynamic processes in mitochondrial quantity and quality control, emphasizing their impact on the neurological system in Charcot–Marie–Tooth disease type 2A, amyotrophic lateral sclerosis, Friedrich’s ataxia, dominant optic atrophy, and Alzheimer’s, Huntington’s, and Parkinson’s diseases. In addition to mechanisms and concepts, we explore in detail different technical approaches for measuring mitochondrial dynamic dysfunction in vitro, describe how results from tissue culture studies may be applied to a better understanding of mitochondrial dysdynamism in human neurodegenerative diseases, and suggest how this experimental platform can be used to evaluate candidate therapeutics in different diseases or in individual patients sharing the same clinical diagnosis.

The Role of Mitochondrial Dynamic Dysfunction in Age-Associated Type 2 Diabetes.

Mitochondrial dynamics, such as fusion and fission, play a critical role in maintaining cellular metabolic homeostasis. The molecular mechanisms underlying these processes include fusion proteins (Mitofusin 1 [MFN1], Mitofusin 2 [MFN2], and optic atrophy 1 [OPA1]) and fission mediators (mitochondrial fission 1 [FIS1] and dynamin-related protein 1 [DRP1]), which interact with each other to ensure mitochondrial quality control. Interestingly, defects in these proteins can lead to the loss of mitochondrial DNA (mtDNA) integrity, impairment of mitochondrial function, a severe alteration of mitochondrial morphology, and eventually cell death. Emerging evidence has revealed a causal relationship between dysregulation of mitochondria dynamics and age-associated type 2 diabetes, a metabolic disease whose rates have reached an alarming epidemic-like level with the majority of cases (59%) recorded in men aged 65 and over. In this sense, fragmentation of mitochondrial networks is often associated with defects in cellular energy production and increased apoptosis, leading, in turn, to excessive reactive oxygen species release, mitochondrial dysfunction, and metabolic alterations, which can ultimately contribute to β-cell dysfunction and insulin resistance. The present review discusses the processes of mitochondrial fusion and fission and their dysfunction in type 2 diabetes, with special attention given to the therapeutic potential of targeting mitochondrial dynamics in this complex metabolic disorder.

Players in Mitochondrial Dynamics and Female Reproduction.

Mitochondrial dynamics (fission and fusion) are essential physiological processes for mitochondrial metabolic function, mitochondrial redistribution, and mitochondrial quality control. Various proteins are involved in regulating mitochondrial dynamics. Aberrant expression of these proteins interferes with mitochondrial dynamics and induces a range of diseases. Multiple therapeutic approaches have been developed to treat the related diseases in recent years, but their curative effects are limited. Meanwhile, the role of mitochondrial dynamics in female reproductive function has attracted progressively more attention, including oocyte development and maturation, fertilization, and embryonic development. Here, we reviewed the significance of mitochondrial dynamics, proteins involved in mitochondrial dynamics, and disorders resulting from primary mitochondrial dynamic dysfunction. We summarized the latest therapeutic approaches of hereditary mitochondrial fusion–fission abnormalities and reviewed the recent advances in female reproductive mitochondrial dynamics.

Emerging small-molecule therapeutic approaches for Alzheimer's disease and Parkinson's disease based on targeting microRNAs.

Emerging small-molecule therapeutic approaches for Alzheimer's disease and Parkinson's disease based on targeting microRNAs.

Dysfunction of Mitochondrial Dynamics in Drosophila Model of Diabetic Nephropathy

Although mitochondrial dysfunction is associated with the development and progression of diabetic nephropathy (DN), its mechanisms are poorly understood, and it remains debatable whether mitochondrial morphological change is a cause of DN. In this study, a Drosophila DN model was established by treating a chronic high-sucrose diet that exhibits similar phenotypes in animals. Results showed that flies fed a chronic high-sucrose diet exhibited a reduction in lifespan, as well as increased lipid droplets in fat body tissue. Furthermore, the chronic high-sucrose diet effectively induced the morphological abnormalities of nephrocytes in Drosophila. High-sucrose diet induced mitochondria fusion in nephrocytes by increasing Opa1 and Marf expression. These findings establish Drosophila as a useful model for studying novel regulators and molecular mechanisms for imbalanced mitochondrial dynamics in the pathogenesis of DN. Furthermore, understanding the pathology of mitochondrial dysfunction regarding morphological changes in DN would facilitate the development of novel therapeutics.

Inhibition of Drp1 Sensitizes Cancer Cells to Cisplatin-Induced Apoptosis through Transcriptional Inhibition of c-FLIP Expression.

Mitochondrial fragmentation occurs during the apoptosis. Dynamin-related protein 1 (Drp1) acts as an important component in mitochondrial fission machinery and can regulate various biological processes including apoptosis, cell cycle, and proliferation. The present study demonstrates that dysfunction of mitochondrial dynamics plays a pivotal role in cisplatin-induced apoptosis. Inhibiting the mitochondrial fission with the specific inhibitor (Mdivi-1) did not affect apoptotic cell death in low concentrations (<10 μM). Interestingly, mdivi-1 enhanced cisplatin-induced apoptosis in cancer cells, but not in normal cells. Particularly in the presence of mdivi-1, several human cancer cell lines, including renal carcinoma cell line Caki-1, became vulnerable to cisplatin by demonstrating the traits of caspase 3-dependent apoptosis. Combined treatment induced downregulation of c-FLIP expression transcriptionally, and ectopic expression of c-FLIP attenuated combined treatment-induced apoptotic cell death with mdivi-1 plus cisplatin. Collectively, our data provide evidence that mdivi-1 might be a cisplatin sensitizer.

MIEF2 over-expression promotes tumor growth and metastasis through reprogramming of glucose metabolism in ovarian cancer

BackgroundIncreasing evidence has revealed the close link between mitochondrial dynamic dysfunction and cancer. MIEF2 (mitochondrial elongation factor 2) is mitochondrial outer membrane protein that functions in the regulation of mitochondrial fission. However, the expression, clinical significance and biological functions of MIEF2 are still largely unclear in human cancers, especially in ovarian cancer (OC).MethodsThe expression and clinical significance of MIEF2 were determined by qRT-PCR, western blot and immunohistochemistry analyses in tissues and cell lines of OC. The biological functions of MIEF2 in OC were determined by in vitro and in vivo cell growth and metastasis assays. Furthermore, the effect of MIEF2 on metabolic reprogramming of OC was determined by metabolomics and glucose metabolism analyses.ResultsMIEF2 expression was significantly increased in OC mainly due to the down-regulation of miR-424-5p, which predicts poor survival for patients with OC. Knockdown of MIEF2 significantly suppressed OC cell growth and metastasis both in vitro and in vivo by inhibiting G1-S cell transition, epithelial-to-mesenchymal transition (EMT) and inducing cell apoptosis, while forced expression of MIEF2 had the opposite effects. Mechanistically, mitochondrial fragmentation-suppressed cristae formation and thus glucose metabolism switch from oxidative phosphorylation to glycolysis was found to be involved in the promotion of growth and metastasis by MIEF2 in OC cells.ConclusionsMIEF2 plays a critical role in the progression of OC and may serve as a valuable prognostic biomarker and therapeutic target in the treatment of this malignancy.

Automated Quantification of Mitochondrial Fragmentation in an In Vitro Parkinson's Disease Model.

Neuronal mitochondrial fragmentation is a phenotype exhibited in models of neurodegeneration such as Parkinson's disease. Delineating the dysfunction in mitochondrial dynamics found in diseased states can aid our understanding of underlying mechanisms of disease progression and possibly identify novel therapeutic approaches. Advances in microscopy and the availability of intuitive open-access software have accelerated the rate of image acquisition and analysis, respectively. These developments allow routine biology researchers to rapidly turn hypotheses into results. In this protocol, we describe the utilization of cell culture techniques, high-content imaging (HCI), and the subsequent open-source image analysis pipeline for the quantification of mitochondrial fragmentation in the context of a rotenone-based in vitro Parkinson's disease model. © 2020 The Authors. Basic Protocol 1: SN4741 neuron culture and treatment in a rotenone-based model of Parkinson's disease Basic Protocol 2: Identification of cell nuclei, measurement of mitochondrial membrane potential, and measurement of mitochondrial fragmentation in mouse-derived midbrain dopaminergic neurons.

Insight into human Miro1/2 domain organization based on the structure of its N-terminal GTPase

Dysfunction in mitochondrial dynamics is believed to contribute to a host of neurological disorders and has recently been implicated in cancer metastasis. The outer mitochondrial membrane adapter protein Miro functions in the regulation of mitochondrial mobility and degradation, however, the structural basis for its roles in mitochondrial regulation remain unknown. Here, we report a 1.7Å crystal structure of N-terminal GTPase domain (nGTPase) of human Miro1 bound unexpectedly to GTP, thereby revealing a non-catalytic configuration of the putative GTPase active site. We identify two conserved surfaces of the nGTPase, the “SELFYY” and “ITIP” motifs, that are potentially positioned to mediate dimerization or interaction with binding partners. Additionally, we report small angle X-ray scattering (SAXS) data obtained from the intact soluble HsMiro1 and its paralog HsMiro2. Taken together, the data allow modeling of a crescent-shaped assembly of the soluble domain of HsMiro1/2. PDB rseferenceCrystal structure of the human Miro1 N-terminal GTPase bound to GTP, 6D71.

Two separate functions of NME3 critical for cell survival underlie a neurodegenerative disorder

We report a patient who presented with congenital hypotonia, hypoventilation, and cerebellar histopathological alterations. Exome analysis revealed a homozygous mutation in the initiation codon of the NME3 gene, which encodes an NDP kinase. The initiation-codon mutation leads to deficiency in NME3 protein expression. NME3 is a mitochondrial outer-membrane protein capable of interacting with MFN1/2, and its depletion causes dysfunction in mitochondrial dynamics. Consistently, the patient's fibroblasts were characterized by a slow rate of mitochondrial dynamics, which was reversed by expression of wild-type or catalytic-dead NME3. Moreover, glucose starvation caused mitochondrial fragmentation and cell death in the patient's cells. The expression of wild-type and catalytic-dead but not oligomerization-attenuated NME3 restored mitochondrial elongation. However, only wild-type NME3 sustained ATP production and viability. Thus, the separate functions of NME3 in mitochondrial fusion and NDP kinase cooperate in metabolic adaptation for cell survival in response to glucose starvation. Given the critical role of mitochondrial dynamics and energy requirements in neuronal development, the homozygous mutation in NME3 is linked to a fatal mitochondrial neurodegenerative disorder.

Modulation of Mitochondrial Dynamics in Neurodegenerative Diseases: An Insight Into Prion Diseases.

Mitochondrial dysfunction is a common and prominent feature of prion diseases and other neurodegenerative disorders. Mitochondria are dynamic organelles that constantly fuse with one another and subsequently break apart. Defective or superfluous mitochondria are usually eliminated by a form of autophagy, referred to as mitophagy, to maintain mitochondrial homeostasis. Mitochondrial dynamics are tightly regulated by processes including fusion and fission. Dysfunction of mitochondrial dynamics can lead to the accumulation of abnormal mitochondria and contribute to cellular damage. Neurons are among the cell types that consume the most energy, have a highly complex morphology, and are particularly dependent on mitochondrial functions and dynamics. In this review article, we summarize the molecular mechanisms underlying the mitochondrial dynamics and the regulation of mitophagy and discuss the dysfunction of these processes in the progression of prion diseases and other neurodegenerative disorders. We have also provided an overview of mitochondrial dynamics as a therapeutic target for neurodegenerative diseases.

Docosahexaenoic Acid Alleviates Oxidative Stress-Based Apoptosis Via Improving Mitochondrial Dynamics in Early Brain Injury After Subarachnoid Hemorrhage.

Mitochondrial dysfunction is considered a crucial therapeutic target for early brain injury following subarachnoid hemorrhage (SAH). Emerging evidence indicates that docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects mitochondria in various chronic diseases. This study aimed to investigate the neuroprotective effects of DHA on mitochondrial dynamic dysfunction after EBI using in vivo and in vitro approaches. For in vivo experiments, the rat endovascular perforation SAH model was performed, whereby DHA was administered intravenously 1h after induction of SAH. Primary cultured neurons treated with oxyhemoglobin (OxyHb) for 24h were used to mimic SAH in vitro. Our results demonstrated that DHA improved neurological deficits and reduced brain edema in rats with SAH, and attenuated OxyHb-induced neuronal death in primary cultured cells. DHA reduced the amount of reactive oxygen species-positive cells and improved cell viability when compared to the SAH + vehicle group in vitro. DHA attenuated malondialdehyde levels and superoxide dismutase stress, increased Bcl2 and Bcl-xl, and decreased Bax and cleaved caspase-3 in vivo. Additionally, DHA ameliorated mitochondrial dysfunction, upregulated the mitochondrial fusion-related protein Optic Atrophy 1, and downregulated the mitochondrial fission-related protein Dynamin-Related-Protein 1 (Drp1) and Serine 616 phosphorylated Drp1 after SAH both in vitro and in vivo. Taken together, our current study demonstrates that DHA might prevent oxidative stress-based apoptosis after SAH. The characterization of the underlying molecular mechanisms may further improve mitochondrial dynamics-related signaling pathways.

Mitochondrial Defects in Primary Osteocytes Derived from an ALS Mouse Model

While motor neuron death is a pathological hallmark of amyotrophic lateral sclerosis (ALS), defects in other cell types may also contribute to ALS disease progression. ALS patients experience progressive muscle wasting that may not only exacerbate neuronal degeneration, but likely has a significant impact on bone function. In our previous study, we have discovered severe bone loss in an ALS mouse model (G93A). The reduced bone density is closely related to the development of muscle atrophy. In the current study, we examined mitochondria in osteocytes derived from the same ALS model at different disease stages. We found that abnormal mitochondrial network and dynamics in primary osteocytes only occur in ALS mice after the ALS disease onset, indicating that mitochondria in osteocytes respond to muscle atrophy during ALS progression. Remarkably, the ALS mutation also directly causes mitochondrial dysfunction independent of muscle atrophy, because we observed abnormal mitochondrial morphology and motility in cultured osteocytes (MLO-Y4) with overexpression of mitochondrial targeted SOD1G93A, when compared with osteocytes overexpressing the wild type SOD1. In addition, the overexpression of SOD1G93A enhanced the expression level of Dynamin-related protein 1 (Drp1), a key protein promoting mitochondrial fission activity, and reduced the expression level of optic atrophy protein 1 (OPA1), a key protein related to mitochondrial fusion. A specific mitochondrial fission inhibitor (Mdivi-1) partially reversed the effect of SOD1G93A on mitochondrial network and dynamics, indicating that SOD1G93A likely promotes mitochondrial fission, but suppresses the fusion activity. Our data provide the first evidence that mitochondria show abnormality in osteocytes derived from an ALS mouse model. The accumulation of mutant SOD1G93A protein inside mitochondria directly causes dysfunction in mitochondrial dynamics in cultured osteocytes, which could be a potential mechanism underlying the bone loss during ALS progression.

ALS-associated mutation SOD1G93A leads to abnormal mitochondrial dynamics in osteocytes

While the death of motor neuron is a pathological hallmark of amyotrophic lateral sclerosis (ALS), defects in other cell types or organs may also actively contribute to ALS disease progression. ALS patients experience progressive skeletal muscle wasting that may not only exacerbate neuronal degeneration, but likely has a significant impact on bone function. In our previous published study, we have discovered severe bone loss in an ALS mouse model with overexpression of ALS-associated mutation SOD1G93A (G93A). Here we further provide a mechanistic understanding of the bone loss in ALS animal and cellular models. Combining mitochondrial fluorescent indicators and confocal live cell imaging, we discovered abnormalities in mitochondrial network and dynamics in primary osteocytes derived from the same ALS mouse model G93A. Those mitochondrial defects occur in ALS mice after the onset of neuromuscular symptoms, indicating that mitochondria in bone cells respond to muscle atrophy during ALS disease progression. To examine whether ALS mutation has a direct contribution to mitochondrial dysfunction independent of muscle atrophy, we evaluated mitochondrial morphology and motility in cultured osteocytes (MLO-Y4) with overexpression of mitochondrial targeted SOD1G93A. Compared with osteocytes overexpressing the wild type SOD1 as a control, the SOD1G93A osteocytes showed similar defects in mitochondrial network and dynamic as that of the primary osteocytes derived from the ALS mouse model. In addition, we further discovered that overexpression of SOD1G93A enhanced the expression level of dynamin-related protein 1 (Drp1), a key protein promoting mitochondrial fission activity, and reduced the expression level of optic atrophy protein 1 (OPA1), a key protein related to mitochondrial fusion. A specific mitochondrial fission inhibitor (Mdivi-1) partially reversed the effect of SOD1G93A on mitochondrial network and dynamics, indicating that SOD1G93A likely promotes mitochondrial fission, but suppresses the fusion activity. Our data provide the first evidence that mitochondria show abnormality in osteocytes derived from an ALS mouse model. The accumulation of mutant SOD1G93A protein inside mitochondria directly causes dysfunction in mitochondrial dynamics in cultured MLO-Y4 osteocytes. In addition, the ALS mutation SOD1G93A-mediated dysfunction in mitochondrial dynamics is associated with an enhanced apoptosis in osteocytes, which could be a potential mechanism underlying the bone loss during ALS progression.

The Two GTPase Domains of the Outer Mitochondrial Membrane Protein Miro have Novel Active Site Conformations and Distinct Biochemical Properties

Mitochondria motility and dynamics are tightly linked. Dysfunction in mitochondrial dynamics cause a host of neurological disorders. The outer mitochondrial membrane protein Miro contains two GTPase domains that control mitochondrial dynamics. While it is known that each of Miro's GTPases are responsible for different mitochondrial morphology and localization phenotypes, the biochemical and structural mechanisms are unknown. We have determined the crystal structure of the entire human Miro1 protein in two separate fragments. Using SAXS and MD, we have investigated how the full-length protein assembles. Our structures reveal significant differences between the n-terminal and c-terminal GTPases (nGTPase and cGTPase). In the nGTPase, unique Switch 1 and Switch 2 residues coordinate the bound GTP, Mg2+, and water molecules for hydrolysis. In contrast, the cGTPase shows no large conformational changes between different nucleotide states and may be catalytically inactive. We demonstrate previous activity mutations based on Ras do not represent GDP/GTP states as previously thought. We have also characterized the V. cholera protein VopE, the first GTPase activating protein (GAP) reported for Miro. Using SEC-MALS, SAXS, and NMR, we are studying the structure of VopE and how it interacts with Miro. Combined with previous results and sequence analyses, our structures suggest that Miro's nGTPase, but not its cGTPase, acts as a nucleotide-dependent switch to control mitochondrial morphology. Our new mutagenesis studies and protein activator tools will allow for more careful dissection of Miro's precise function in vivo.

Phyllanthus urinaria's Inhibition of Human Osteosarcoma Xenografts Growth in Mice is Associated with Modulation of Mitochondrial Fission/Fusion Machinery.

Osteosarcoma is an aggressive bone cancer arising from primitive transformed cells of mesenchymal origin to form malignant osteoid. Phyllanthus urinaria [Formula: see text]P. urinaria[Formula: see text] is a widely used folk medicine in cancer treatment, however the mechanism of P. urinaria inhibited human osteosarcoma is unclear. The present study was aimed at investigating the antitumoral effects of an aqueous P. urinaria on human osteosarcoma in vivo and the related underlying mechanisms, mainly focusing on mitochondrial dynamic dysfunction. Our results showed that oral administration of P. urinaria to mice led to significant inhibition of tumor development without substantial changes to body weight or major organs. Histological examinations with H&E, Giemsa, and Masson trichrome stains confirmed inhibition of tumor growth by the P. urinaria treatment. Immunohistochemical staining of proliferation markers antigen KI-67 (Ki67) and proliferating cell nuclear antigen (PCNA), as well as a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay demonstrated a decrease of tumor proliferation and an increase of apoptosis, which was associated with the modulation of B-cell lymphoma 2 (Bcl-2) family activating the caspase cascade in the P. urinaria-treated mice. The neovascularization marker cluster of differentiation 31 (CD31) was inhibited in P. urinaria-treated xenografts, implicating the potential anti-angiogenic effect of P. urinaria. P. urinaria treatment resulted in a significant decrease in the mitochondrial fusion proteins, including mitofusin 1/2 (Mfn1/2) and optic atrophy type 1 (Opa1), as well as an increase in the fission protein dynamin-related protein 1 (Drp1). The results of this study suggest mitochondrial dysfunction is associated with dynamic change that is involved in the apoptosis and anti-angiogenesis elicited by P. urinaria.

Effects of Astragalus Polysaccharides on Dysfunction of Mitochondrial Dynamics Induced by Oxidative Stress.

This paper studied the chronic fatigue induced by excessive exercise and the restoration effects of Astragalus polysaccharides (APS) on mitochondria. In vivo, we found that excessive exercise could cause oxidative stress statue which led to morphological and functional changes of mitochondria. The changes, including imbalance between mitochondria fusion-fission processes, activation of mitophagy, and decrease of PGC-1α expression, could be restored by APS. We further confirmed in vitro, and what is more, we found that APS may ameliorate mitochondrial dysfunction through Sirt1 pathway. Based on the results, we may figure out part of the molecular mechanism of mitochondrial amelioration by APS.