Currently, the incidence of Parkinson's disease (PD) is on the rise. More and more evidences suggest that mitochondrial dysfunction plays a crucial role in the etiology of PD, and dysfunction of mitochondrial complex I (MCI) is one of the most critical factors leading to mitochondrial dysfunction. On one hand, MCI dysfunction stimulates dopaminergic neurons to produce reactive oxygen species (ROS). On the other hand, MCI dysfunction decreases dopaminergic neuron viability and reduces ATP production. All these outcomes promote the pathological progression of PD. This review summarizes research progress on the role of MCI in the pathogenesis of PD, as well as PD treatment strategies based on MCI.
Parkinson Disease/metabolism* ; Humans ; Electron Transport Complex I/metabolism* ; Mitochondria/physiology* ; Reactive Oxygen Species/metabolism* ; Dopaminergic Neurons/metabolism* ; Animals ; Adenosine Triphosphate/metabolism*

Mitochondrial metabolism is crucial for providing energy and heme precursors during erythroid development. Oxoglutarate dehydrogenase complex (OGDC) is a key enzyme in the mitochondrial tricarboxylic acid (TCA) cycle, and its level gradually increases during erythroid development, indicating its significant role in erythroid development. The aim of the present study was to explore the role and mechanism of OGDC in erythroid development. In this study, we treated erythroid progenitor cells with CPI-613, a novel lipoic acid analog that competitively inhibits OGDC. The results showed that CPI-613 inhibited erythropoietin (EPO)-induced differentiation and enucleation of human CD34⁺ hematopoietic stem cells into erythroid cells, suppressed cell proliferation, and induced apoptosis. The results of <i>in vivoi> experiments showed that CPI-613 also hindered the recovery of mice from acute hemolytic anemia. Further mechanism research results showed that CPI-613 increased reactive oxygen species (ROS) in erythroid progenitor cells, inhibited mitochondrial respiration, caused mitochondrial damage, and suppressed heme synthesis, thereby inhibiting erythroid differentiation. Clinical research results showed that oxoglutarate dehydrogenase (OGDH) protein expression levels were up-regulated in bone marrow cells of polycythemia vera (PV) patients. Treatment with CPI-613 significantly inhibited the excessive proliferation and differentiation of erythroid progenitor cells of the PV patients. These findings demonstrates the critical role of OGDC in normal erythroid development, suggesting that inhibiting its activity could be a novel therapeutic strategy for treating PV.
Animals ; Humans ; Mitochondria/metabolism* ; Mice ; Ketoglutarate Dehydrogenase Complex/physiology* ; Cell Differentiation/drug effects* ; Cells, Cultured ; Erythropoiesis/drug effects* ; Reactive Oxygen Species/metabolism* ; Cell Proliferation/drug effects* ; Erythroid Precursor Cells/cytology* ; Apoptosis/drug effects* ; Thioctic Acid/pharmacology* ; Caprylates ; Sulfides

This study explored the mechanism of Xiangsha Liujunzi Decoction(XSLJZD) in the treatment of functional dyspepsia(FD) based on inositol-requiring enzyme 1(IRE1)/apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase(JNK) pathway-mediated autophagy in interstitial cells of Cajal(ICC). Forty-eight SPF-grade male SD suckling rats were randomly divided into a blank group and a modeling group, and the integrated modeling method(iodoacetamide gavage + disturbance of hunger and satiety + swimming exhaustion) was used to replicate the FD rat model. After the model replications were successfully completed, the rats were divided into a model group, high-dose, medium-dose, and low-dose groups of XSLJZD(12, 6, and 3 g·kg~(-1)·d~(-1)), and a positive drug group(mosapride of 1.35 mg·kg~(-1)·d~(-1)), and the intervention lasted for 14 days. The gastric emptying rate and intestinal propulsion rate of rats in each group were measured. The histopathological changes in the gastric sinus tissue of rats in each group were observed by hematoxylin-eosin(HE) staining. The ultrastructure of ICC was observed by transmission electron microscopy. The immunofluorescence double staining technique was used to detect the protein expression of phospho-IRE1(p-IRE1), TNF receptor associated factors 2(TRAF2), phospho-ASK1(p-ASK1), phospho-JNK(p-JNK), p62, and Beclin1 in ICC of gastric sinus tissue of rats in each group. Western blot was used to detect the related protein expression of gastric sinus tissue of rats in each group. Compared with those in the blank group, the rats in the model group showed decreased body weight, gastric emptying rate, and intestinal propulsion rate, and transmission electron microscopy revealed damage to the endoplasmic reticulum structure and increased autophagosomes in ICC. Immunofluorescence staining revealed that the ICC of gastric sinus tissue showed a significant elevation of p-IRE1, TRAF2, p-ASK1, p-JNK, and Beclin1 proteins and a significant reduction of p62 protein. Western blot revealed that the expression levels of relevant proteins in gastric sinus tissue were consistent with those of proteins in ICC. Compared with the model group, the body weight of rats in the high-dose and medium-dose groups of XSLJZD was increased, and the gastric emptying rate and intestinal propulsion rate were increased. Transmission electron microscopy observed amelioration of structural damage to the endoplasmic reticulum of ICC and reduction of autophagosomes, and the p-IRE1, TRAF2, p-ASK1, p-JNK, and Beclin1 proteins in the ICC of gastric sinus tissue were significantly decreased. The p62 protein was significantly increased. Western blot revealed that the expression levels of relevant proteins in gastric sinus tissue were consistent with those of proteins in ICC. XSLJZD can effectively treat FD, and its specific mechanism may be related to the inhibition of the expression of molecules related to the endoplasmic reticulum stress IRE1/ASK1/JNK pathway in ICC and the improvement of autophagy to promote gastric motility in ICC.
Animals ; Male ; Drugs, Chinese Herbal/administration & dosage* ; Autophagy/drug effects* ; Rats ; Rats, Sprague-Dawley ; Interstitial Cells of Cajal/metabolism* ; Dyspepsia/physiopathology* ; Protein Serine-Threonine Kinases/genetics* ; MAP Kinase Kinase Kinase 5/genetics* ; MAP Kinase Signaling System/drug effects* ; Humans ; Endoribonucleases/genetics* ; Multienzyme Complexes

This study aimed to investigate the effect and mechanism of Buyang Huanwu Decoction in regulating endoplasmic reticulum stress via the inositol-requiring enzyme 1α(IRE1α)/apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase(JNK) pathway to improve neurological function in rats with cerebral ischemia/reperfusion injury(CIRI). SPF-grade male sprague-dawley(SD) rats were randomly divided into Sham group, model group, Buyang Huanwu Decoction group, and edaravone group. Except for the Sham group, the other groups were subjected to the modified suture method to establish a middle cerebral artery occlusion/reperfusion(MCAO/R) model. After treatment, neurological function was assessed using the Zea Longa scoring system. Gait analysis was used to detect the motor function. Detection of relative infarct area in brain tissue using 2,3,5-triphenyltetrazolium chloride(TTC) staining. Nissl staining was used to observe the structure of neuronal cells. Western blot and real-time fluorescence quantitative PCR(RT-qPCR) were used to detect IRE1α, ASK1, JNK, B cell lymphoma-2(Bcl-2), Bcl-2 related X protein(Bax), and Caspase-3 in the brain tissue. Immunohistochemistry was used to detect the positive expression of IRE1α, ASK1, and JNK. Immunofluorescence was used to detect the fluorescence expression levels of Bax, Bcl-2, and Caspase-3. The results showed that compared with the Sham group, the model group exhibited increased neurological scores(P<0.01), increased ratio of ground contact area and strength in both forelimbs(P<0.01), enlarged relative infarct area of brain tissue(P<0.05), and a reduced number of Nissl staining-positive cells(P<0.01). The protein and mRNA expression levels of IRE1α, ASK1, JNK, Bax, and Caspase-3 in brain tissue were significantly elevated, while those of Bcl-2 were decreased(P<0.05). Compared with the model group, both the Buyang Huanwu Decoction group and edaravone group showed reduced neurological scores(P<0.05), decreased ratio of ground contact area and strength in both forelimbs(P<0.05), smaller relative infarct area(P<0.05), alleviated neuronal damage, and increased number of Nissl staining-positive cells(P<0.05). The expression levels of IRE1α, ASK1, JNK, Bax, and Caspase-3 protein and mRNA in brain tissue were significantly reduced, while those of Bcl-2 were significantly increased(P<0.05). The results indicated that Buyang Huanwu Decoction can effectively improve brain injury in CIRI rats, and its mechanism of action may be related to regulating the endoplasmic reticulum stress IRE1α/ASK1/JNK signaling pathway.
Animals ; Male ; Rats, Sprague-Dawley ; Protein Serine-Threonine Kinases/genetics* ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; MAP Kinase Kinase Kinase 5/genetics* ; Ischemic Stroke/physiopathology* ; Humans ; MAP Kinase Signaling System/drug effects* ; Apoptosis/drug effects* ; Endoribonucleases/genetics* ; JNK Mitogen-Activated Protein Kinases/genetics* ; Endoplasmic Reticulum Stress/drug effects* ; Multienzyme Complexes

OBJECTIVES: To study the clinical characteristics and treatment outcomes of <i>GNEi> gene-related thrombocytopenia. METHODS: A retrospective analysis was conducted on the data of one child with <i>GNEi> gene-related thrombocytopenia, along with a review of cases reported in the literature, focusing on clinical phenotypes and treatment characteristics. RESULTS: Among 31 patients, the onset was primarily in the neonatal period or early childhood, characterized by mucocutaneous bleeding. Twenty-six cases presented with macrothrombocytes, and 4 cases progressed to <i>GNEi> myopathy in adulthood. Overall treatment efficacy was suboptimal, although 5 cases responded well to thrombopoietic agents. CONCLUSIONS <i>GNEi> gene-related thrombocytopenia is characterized by moderate to severe thrombocytopenia, macrothrombocytes, and a bleeding tendency. Some children may develop secondary <i>GNEi> myopathy, highlighting the need for early identification and exploration of effective therapies.
Child ; Humans ; Multienzyme Complexes/genetics* ; Thrombocytopenia/drug therapy*

OBJECTIVE: To investigate the effects of astragaloside IV (AS-IV) on podocyte injury of diabetic nephropathy (DN) and reveal its potential mechanism. METHODS: In in vitro experiment, podocytes were divided into 4 groups, normal, high glucose (HG), inositol-requiring enzyme 1 (IRE-1) α activator (HG+thapsigargin 1 µmol/L), and IRE-1α inhibitor (HG+STF-083010, 20 µmol/L) groups. Additionally, podocytes were divided into 4 groups, including normal, HG, AS-IV (HG+AS-IV 20 µmol/L), and IRE-1α inhibitor (HG+STF-083010, 20 µmol/L) groups, respectively. After 24 h treatment, the morphology of podocytes and endoplasmic reticulum (ER) was observed by electron microscopy. The expressions of glucose-regulated protein 78 (GRP78) and IRE-1α were detected by cellular immunofluorescence. In in vivo experiment, DN rat model was established via a consecutive 3-day intraperitoneal streptozotocin (STZ) injections. A total of 40 rats were assigned into the normal, DN, AS-IV [AS-IV 40 mg/(kg·d)], and IRE-1α inhibitor [STF-083010, 10 mg/(kg·d)] groups (n=10), respectively. The general condition, 24-h urine volume, random blood glucose, urinary protein excretion rate (UAER), urea nitrogen (BUN), and serum creatinine (SCr) levels of rats were measured after 8 weeks of intervention. Pathological changes in the renal tissue were observed by hematoxylin and eosin (HE) staining. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expressions of GRP78, IRE-1α, nuclear factor kappa Bp65 (NF-κBp65), interleukin (IL)-1β, NLR family pyrin domain containing 3 (NLRP3), caspase-1, gasdermin D-N (GSDMD-N), and nephrin at the mRNA and protein levels in vivo and in vitro, respectively. RESULTS: Cytoplasmic vacuolation and ER swelling were observed in the HG and IRE-1α activator groups. Podocyte morphology and ER expansion were improved in AS-IV and IRE-1α inhibitor groups compared with HG group. Cellular immunofluorescence showed that compared with the normal group, the fluorescence intensity of GRP78 and IRE-1α in the HG and IRE-1α activator groups were significantly increased whereas decreased in AS-IV and IRE-1α inhibitor groups (P<0.05). Compared with the normal group, the mRNA and protein expressions of GRP78, IRE-1α, NF-κ Bp65, IL-1β, NLRP3, caspase-1 and GSDMD-N in the HG group was increased (P<0.05). Compared with HG group, the expression of above indices was decreased in the AS-IV and IRE-1α inhibitor groups, and the expression in the IRE-1α activator group was increased (P<0.05). The expression of nephrin was decreased in the HG group, and increased in AS-IV and IRE-1α inhibitor groups (P<0.05). The in vivo experiment results revealed that compared to the normal group, the levels of blood glucose, triglyceride, total cholesterol, BUN, blood creatinine and urinary protein in the DN group were higher (P<0.05). Compared with DN group, the above indices in AS-IV and IRE-1α inhibitor groups were decreased (P<0.05). HE staining revealed glomerular hypertrophy, mesangial widening and mesangial cell proliferation in the renal tissue of the DN group. Compared with the DN group, the above pathological changes in renal tissue of AS-IV and IRE-1α inhibitor groups were alleviated. Quantitative RT-PCR and Western blot results of GRP78, IRE-1α, NF-κ Bp65, IL-1β, NLRP3, caspase-1 and GSDMD-N were consistent with immunofluorescence analysis. CONCLUSION AS-IV could reduce ERS and inflammation, improve podocyte pyroptosis, thus exerting a podocyte-protective effect in DN, through regulating IRE-1α/NF-κ B/NLRP3 signaling pathway.
Podocytes/metabolism* ; Animals ; Diabetic Nephropathies/metabolism* ; Saponins/therapeutic use* ; Triterpenes/therapeutic use* ; Signal Transduction/drug effects* ; NF-kappa B/metabolism* ; Protein Serine-Threonine Kinases/metabolism* ; Male ; Rats, Sprague-Dawley ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Endoribonucleases/metabolism* ; Endoplasmic Reticulum Chaperone BiP ; Rats ; Diabetes Mellitus, Experimental/complications* ; Endoplasmic Reticulum/metabolism* ; Multienzyme Complexes

OBJECTIVES: Uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is a progressive neurodegenerative disease associated with homozygous or compound heterozygous missense mutations in the <i>GNEi> gene. This study aims to explore the impact of the homozygous p.V543M mutation in on cell phenotype and to gain preliminary insights into the underlying mechanisms. METHODS: Human embryonic kidney 293T (HEK 293T) cells were used to construct wild-type (WT-GNE) and mutant (MUT-GNE) <i>GNEi> overexpression models. Western blotting and immunofluorescence were used to assess GNE protein expression levels and subcellular localization. Cell adhesion, proliferation, apoptosis, and mitochondrial membrane potential were evaluated using the cell counting kit-8 (CCK-8) assay, crystal violet staining, flow cytometry, Hoechst 33342/propidium iodide (PI) staining, and tetramethylrhodamine ethyl ester (TMRE) staining. Sialic acid synthesis levels and GNE enzymatic activity were measured, and the mRNA expression of sialic acid biosynthesis-related enzymes was quantified by real-time PCR. RESULTS: Western blotting confirmed successful establishment of <i>GNEi> overexpression models. Immunofluorescence showed significantly reduced co-localization of GNE protein with Golgin-97 in the MUT-GNE group compared to WT-GNE (Pearson's correlation coefficient: 0.65±0.08 vs 0.83±0.06, <i>Pi><0.05). Compared with WT-GNE, cells in the MUT-GNE group exhibited increased adhesion, decreased proliferation, and reduced mitochondrial membrane potential (<i>Pi><0.05). No significant differences in apoptosis were observed between groups. The MUT-GNE group showed reduced sialic acid production, significantly decreased kinase activity, and downregulated transcription of sialic acid biosynthesis-related enzymes compared to WT-GNE (<i>Pi><0.001). CONCLUSIONS The p.V543M mutation in the <i>GNEi> gene alters cellular phenotype by reducing GNE enzymatic activity and the transcription of sialic acid biosynthesis enzymes, ultimately impairing sialic acid production.
Humans ; Mutation, Missense ; HEK293 Cells ; Apoptosis/genetics* ; Phenotype ; Multienzyme Complexes/metabolism* ; Cell Proliferation ; Homozygote ; Cell Adhesion/genetics* ; Distal Myopathies/genetics*

L-tyrosine is one of the 20 amino acids that make up proteins and is an essential amino acid for mammals, often used as a nutritional supplement. The conventional methods for synthesizing L-tyrosine have some problems such as the production of many by-products, high requirements for production conditions, and environmental pollution. In this study, we designed and constructed a multi-enzyme cascade for the synthesis of L-tyrosine with alanine, glutamate, ammonium chloride, and phenol as substrates. Initially, the sources of glutamate oxidase, alanine aminotransferase, and tyrosine phenol lyase were screened and analyzed, which was followed by the identification of the rate-limiting enzyme in the reaction process. A colorimetric screening method was established, and the rate-limiting enzyme <i>Dbi>AlaA was engineered to enhance its activity by 40.0%. Subsequently, the reaction conditions, including temperature, pH, cell concentration, and surfactant and coenzyme dosages, were optimized. After optimization, the yield of L-tyrosine reached 9.93 g/L, with a alanine conversion rate of 54.90%. Finally, a feed-batch fermentation strategy was adopted, and the yield of L-tyrosine reached 56.07 g/L after 24 h, with a alanine conversion rate of 65.22%. This study provides a reference for the whole-cell catalytic synthesis of L-tyrosine and its industrialization.
Tyrosine/biosynthesis* ; Escherichia coli/metabolism* ; Tyrosine Phenol-Lyase/genetics* ; Multienzyme Complexes/metabolism* ; Fermentation

L-phosphinothricin (L-PPT) is an efficient broad-spectrum herbicide. To realize the multi-enzyme catalytic preparation of L-PPT, we constructed an engineered strain <i>Escherichia colii> YM-1 for efficient expression of D-amino acid transaminase, which could catalyze the generation of the intermediate 2-oxo-4-[(hydroxymethylphosphonyl)] butyric acid (PPO) from D-phosphinothricin (D-PPT). In addition, <i>Ei>. <i>colii> pLS was constructed to co-express glutamate dehydrogenase and glucose dehydrogenase, which not only catalyzed the generation of L-PPT from PPO but also regenerated the coenzyme nicotinamide adenine dinucleotide phosphate (NADPH). A fed-batch fermentation process was then established for <i>Ei>. <i>colii> YM-1 and pLS, and the apparent activities of D-amino acid transaminase and glutamate dehydrogenase were increased by 22.68% and 100.82%, respectively, compared with those in shake flasks. The process parameters were optimized for the catalytic preparation of L-PPT by whole-cell cascade of <i>Ei>. <i>colii> YM-1 and pLS with D, L-PPT as the substrate. After reaction for 8 h, 91.36% conversion of D-PPT was achieved, and the enantiomeric excess of L-PPT reached 90.22%. The findings underpin the industrial production of L-PPT.
Escherichia coli/enzymology* ; Aminobutyrates/metabolism* ; Glutamate Dehydrogenase/biosynthesis* ; Glucose 1-Dehydrogenase/biosynthesis* ; Herbicides/metabolism* ; Multienzyme Complexes/metabolism* ; Transaminases/metabolism* ; Phosphinic Acids/metabolism*

Photosynthesis in plants directly affects the synthesis and accumulation of organic matter, which directly influences crop yield. RNA-binding proteins (RBPs) are involved in the regulation of a variety of physiological functions in plants, while the functions of RBPs in photosynthesis have not been clearly elucidated. To investigate the effect of a glycine-rich RNA-binding protein (SlRBP1) in tomato on plant photosynthesis, a stably inherited <i>SlRBP1i> silenced plant in Alisa Craig was obtained by plant tissue culture using artificial small RNA interference. It turns out that the size of the tomato fruit was reduced and leaves significantly turned yellow. Chlorophyll(Chl) content measurement, Chl fluorescence imaging and chloroplast transmission electron microscopy revealed that the chloroplast morphology and structure of the leaves of tomato amiR-<i>SlRBP1i> silenced plants were disrupted, and the chlorophyll content was significantly reduced. Measurement of photosynthesis rate of wild-type and amiR-<i>SlRBP1i> silenced plants in the same period demonstrated that the photosynthetic rate of these plants was significantly reduced, and analysis of RNA-seq data indicated that silencing of <i>SlRBP1i> significantly reduced the expression of photosynthesis-related genes, such as PsaE, PsaL, and PsbY, and affected the yield of tomato fruits through photosynthesis.
RNA ; Solanum lycopersicum/genetics* ; Photosynthesis/genetics* ; Chlorophyll ; RNA-Binding Proteins/genetics*