Parkinson's disease (PD), a chronic and common neurodegenerative disease, is characterized by the progressive loss of dopaminergic neurons in the dense part of the substantia nigra and abnormal aggregation of alpha-synuclein. Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by chronic insulin resistance and deficiency in insulin secretion. Extensive evidence has confirmed shared pathogenic mechanisms underlying PD and T2DM, such as oxidative stress caused by insulin resistance, mitochondrial dysfunction, inflammation, and disorders of energy metabolism. Conventional drugs for treating T2DM, such as metformin and glucagon-like peptide-1 receptor agonists, affect nerve repair. Even drugs for treating PD, such as levodopa, can affect insulin secretion. This review summarizes the relationship between PD and T2DM and related therapeutic drugs from the perspective of insulin signaling pathways in the brain.
Humans ; Parkinson Disease/drug therapy* ; Diabetes Mellitus, Type 2/pathology* ; Signal Transduction/physiology* ; Receptor, Insulin/metabolism* ; Animals ; Insulin Resistance/physiology* ; Insulin/metabolism*

The mandibular condyle is a critical growth center in craniofacial bone development, especially during postnatal stages. Postnatal condyle osteogenesis requires precise spatiotemporal coordination of growth factor signaling cascades and hierarchical gene regulatory networks. Plagl1, which encodes a zinc finger transcription factor, is a paternally expressed gene. We demonstrate that PLAGL1 is highly expressed in cranial neural crest cell (CNCC)-derived lineage cells in mouse condyles. Using the CNCC-derived lineage-specific Plagl1 knockout mouse model, we evaluate the function of PLAGL1 during postnatal mouse condyle development. Our findings show that PLAGL1 contributes significantly to osteoblast differentiation, and its deficiency impairs osteogenic lineage differentiation, which consequently disrupts mandibular condyle development. Mechanistically, insulin-like growth factor 2 (IGF2) in complex with IGF-binding proteins (IGFBPs) has been identified as the principal PLAGL1 effector responsible for osteogenic regulation during postnatal condyle morphogenesis. Plagl1 deficiency significantly downregulates the IGF2/IGFBP pathway, leading to disordered glucose metabolism, defective extracellular matrix organization, and impaired ossification. Exogenous IGF2 treatment rescues impaired osteoblast differentiation caused by Plagl1 deficiency. In conclusion, the PLAGL1-IGF2 axis is a critical regulator of osteogenesis during mandibular condyle development.
Animals ; Osteogenesis/genetics* ; Insulin-Like Growth Factor II/metabolism* ; Mice ; Transcription Factors/metabolism* ; Mice, Knockout ; Cell Differentiation ; DNA-Binding Proteins/genetics* ; Mandibular Condyle/growth & development* ; Osteoblasts/cytology* ; Signal Transduction ; Neural Crest/cytology*

In this study, araucarene diterpenes, characterized by a pimarene skeleton with a variably oxidized side chain at C-13, were investigated. A total of 16 araucarene diterpenoids and their derivatives were isolated from the woods of Agathis dammara, including 11 previously unreported compounds: dammaradione (1), dammarones D-G (2, 5, 14, 15), dammaric acids B-F (8-12), and dammarol (16). The structures of these new compounds were elucidated using high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS) and one-dimensional/two-dimensional (1D/2D) nuclear magnetic resonance (NMR), while their absolute configurations were determined through the electronic circular dichroism (ECD) exciton chirality method and Snatzke's method. The hypoglycemic activity of all isolated compounds was evaluated using a transgenic zebrafish model, and a structure-activity relationship (SAR) analysis was conducted. Araucarone (3) and dammaric acid C (9), serving as representative compounds, demonstrated significant hypoglycemic effects on zebrafish. The primary mechanism involves the promotion of pancreatic β cell regeneration and glucose uptake. Specifically, these compounds enhance the differentiation of pancreatic endocrine precursor cells (PEP cells) into β cells in zebrafish.
Zebrafish ; Animals ; Diterpenes/isolation & purification* ; Insulin-Secreting Cells/cytology* ; Glucose/metabolism* ; Hypoglycemic Agents/isolation & purification* ; Molecular Structure ; Structure-Activity Relationship ; Plant Extracts/pharmacology* ; Regeneration/drug effects*

Coptis chinensis Franch. and Panax ginseng C. A. Mey. are traditional herbal medicines with millennia of documented use and broad therapeutic applications, including anti-diabetic properties. However, the synergistic effect of total alkaloids from Coptis chinensis and total ginsenosides from Panax ginseng on type 2 diabetes mellitus (T2DM) and its underlying mechanism remain unclear. The research demonstrated that the optimal ratio of total alkaloids from Coptis chinensis and total ginsenosides from Panax ginseng was 4∶1, exhibiting maximal efficacy in improving insulin resistance and gluconeogenesis in primary mouse hepatocytes. This combination demonstrated significant synergistic effects in improving glucose tolerance, reducing fasting blood glucose (FBG), the weight ratio of epididymal white adipose tissue (eWAT), and the homeostasis model assessment of insulin resistance (HOMA-IR) in leptin receptor-deficient (db/db) mice. Subsequently, a T2DM liver-specific network was constructed based on RNA sequencing (RNA-seq) experiments and public databases by integrating transcriptional properties of disease-associated proteins and protein-protein interactions (PPIs). The network recovery index (NRI) score of the combined treatment group with a 4∶1 ratio exceeded that of groups treated with individual components. The research identified that activated adenosine 5'-monophosphate-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling in the liver played a crucial role in the synergistic treatment of T2DM, as verified by western blot experiment in db/db mice. These findings demonstrate that the 4∶1 combination of total alkaloids from Coptis chinensis and total ginsenosides from Panax ginseng significantly improves insulin resistance and glucose and lipid metabolism disorders in db/db mice, surpassing the efficacy of individual treatments. The synergistic mechanism correlates with enhanced AMPK/ACC signaling pathway activity.
Animals ; Panax/chemistry* ; Ginsenosides/administration & dosage* ; Diabetes Mellitus, Type 2/metabolism* ; Mice ; Male ; Alkaloids/pharmacology* ; Coptis/chemistry* ; Drug Synergism ; Insulin Resistance ; Mice, Inbred C57BL ; Humans ; Transcriptome/drug effects* ; Blood Glucose/metabolism* ; Hypoglycemic Agents/administration & dosage* ; Drugs, Chinese Herbal/administration & dosage* ; Hepatocytes/metabolism*

OBJECTIVE: To investigate the effect of moxibustion on central insulin resistance related proteins of the rats suffering from diabetic cognitive decline, and analyze the underlying mechanism of moxibustion for cognition improvement. METHODS: Using the intraperitoneal injection of STZ combined with a high-fat diet, the rat model of diabetic cognitive decline were prepared. Twenty successfully-modeled rats were assigned randomly into a model group and a moxibustion group, 10 rats in each one. Besides, a blank group was set up with 10 rats collected. In the moxibustion group, suspending moxibustion was applied to "Baihui" (GV20), "Shenting" (GV24) and "Dazhui" (GV14) at the same time, 20 min in each intervention, once a day, and 6 interventions were delivered weekly and the duration of treatment was consecutive 4 weeks. The random blood glucose was measured using glucometer, and the learning-memory ability was detected by water maze test. HE staining was used to observe the morphology of neurons in the hippocampal tissue, real-time PCR assay was to detect mRNA expression of insulin receptor substrate 1 (IRS1), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) in the hippocampal tissue. The Western blot method was employed to detect the protein expression of IRS1, PI3K, AKT, phosphorylated IRS1 (p-IRS1), phosphorylated PI3K (p-PI3K) and phosphorylated AKT (p-AKT) in the hippocampal tissue, and the ratio of p-IRS1/IRS1, p-PI3K/PI3K and p-AKT/AKT was calculated separately. The immunofluorescence intensity of p-IRS1, p-PI3K, and p-AKT was measured using immunofluorescence. RESULTS: Compared with the blank group, the rats of the model group exhibited higher random blood glucose (P<0.001), longer escape latency (P<0.001), severe pathological damage in the hippocampus, lower mRNA expression of IRS1, PI3K, and AKT (P<0.001), reduced ratio of p-IRS1/IRS1, p-PI3K/PI3K and p-AKT/AKT (P<0.001), and declined immunofluorescence intensity of p-IRS1, p-PI3K, and p-AKT in the hippocampal tissue (P<0.001). In comparison with the model group, for the rats of the moxibustion group, the random blood glucose decreased (P<0.05), the escape latency was shortened (P<0.01), the hippocampal pathological damage was attenuated, the mRNA expression of IRS1, PI3K and AKT increased (P<0.01), the ratio of p-IRS1/IRS1, p-PI3K/PI3K and p-AKT/AKT was elevated (P<0.01, P<0.05), and the immunofluorescence intensity of p-IRS1, p-PI3K, and p-AKT in the hippocampal tissue was strengthened (P<0.01, P<0.05). CONCLUSION In diabetic rats experiencing cognitive decline, moxibustion can enhance the learning-memory ability, which may be attributed to modulating the protein expression of IRS1, PI3K, and AKT, and their phosphorylation, activating insulin signal transduction, and reducing central insulin resistance.
Animals ; Moxibustion ; Insulin Resistance ; Rats ; Male ; Insulin Receptor Substrate Proteins/genetics* ; Rats, Sprague-Dawley ; Humans ; Proto-Oncogene Proteins c-akt/genetics* ; Cognitive Dysfunction/genetics* ; Diabetes Mellitus, Experimental/therapy* ; Hippocampus/metabolism* ; Acupuncture Points ; Phosphatidylinositol 3-Kinases/genetics*

OBJECTIVE: To explore the effect and mechanism of acupuncture at "Weizhong" (BL40) on microcirculation of paravertebral skeletal muscle in rats with chronic blunt injury of lumbar muscle based on the insulin-like growth factor-1 (IGF-1)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway. METHODS: Forty-eight SPF-grade SD rats were randomized into a blank group (8 rats) and a modeling group (40 rats). Chronic blunt injury model was established by weight impact method in the modeling group. Forty rats were successfully modeled, and were randomly divided into a model group, an acupuncture at Weizhong group (Weizhong group), an acupuncture at non-acupoint group (non-acupoint group), an inhibitor group, and an inhibitor+acupuncture at Weizhong group (inhibitor+Weizhong group), 8 rats in each group. In the Weizhong group and the inhibitor+Weizhong group, acupuncture was applied at bilateral "Weizhong" (BL40). In the non-acupoint group, acupuncture was applied at non-acupoints, i.e. points 0.5 cm inward from bilateral "Weizhong" (BL40). The acupuncture intervention was delivered 20 min each time, once a day for continuous 2 weeks. In the inhibitor group and the inhibitor+Weizhong group, intraperitoneal injection of IGF-1 receptor (IGF-1R) inhibitor was given once a day, at a dosage of 2 mg/100 g, for continuous 2 weeks. Before modeling and on the 1st, 7th and 14th days of intervention, the body mass was measured. Before and after modeling, and after intervention, the limb grip strength and paw withdrawal threshold (PWT) were measured. After intervention, the morphology of psoas muscle was observed by HE staining; the ultrastructure of psoas muscle capillaries was observed by electron microscopy; the levels of serum vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) were detected by ELISA; and the protein and mRNA expression of IGF-1, IGF-1R, PI3K, AKT of psoas muscle was detected by Western blot and real-time PCR. RESULTS: Compared with the blank group, in the model group, the body mass on the 7th and 14th days of intervention, the limb grip strength, and the PWT of left and right hind feet were decreased (P<0.001, P<0.01); the skeletal muscle cells showed enlarged intercellular space, loosely arranged and irregularly shaped, the capillaries in the psoas muscle tissues were edematous, and the lumen of the blood vessels was obviously atrophied; the levels of serum VEGF and eNOS were decreased (P<0.001); in psoas muscle, the protein expression of IGF-1 and IGF-1R, as well as the p-PI3K/PI3K, p-AKT/AKT values were decreased (P<0.001), the mRNA expression of IGF-1, IGF-1R, PI3K and AKT was decreased (P<0.001, P<0.05). Compared with the model group, in the Weizhong group, the body weight was increased on the 7th and 14th days of intervention (P<0.001), the limb grip strength and the PWT of the left and right hind feet were increased (P<0.001, P<0.01); the arrangement of the skeletal muscle cells was relatively tight and the intercellular space was reduced, the blood vessels tended to be regular and the structure of the basement membrane was continuous, while the lumens of blood vessels were collapsed locally; the levels of serum VEGF and eNOS were increased (P<0.001); in psoas muscle, the protein expression of IGF-1 and IGF-1R, as well as the p-PI3K/PI3K, p-AKT/AKT values were increased (P<0.001), the mRNA expression of IGF-1, IGF-1R, PI3K and AKT was increased (P<0.001, P<0.01). Compared with the model group, in the inhibitor group, the body mass was decreased on the 7th and 14th days of intervention (P<0.05, P<0.01); the limb grip strength and the PWT of the left hind foot were decreased (P<0.01, P<0.001); the intercellular space of skeletal muscle cells was larger, the nuclei of the cells and erythrocytes were scattered in the intercellular space, the damage of the capillaries in the muscular tissues was serious, the collagen fibers were sparsely distributed and disorganized; the levels of serum VEGF and eNOS were decreased (P<0.001, P<0.01); in psoas muscle, the protein expression of IGF-1 and IGF-1R, as well as the p-PI3K/PI3K and p-AKT/AKT values were decreased (P<0.01, P<0.05, P<0.001), the mRNA expression of IGF-1, IGF-1R, PI3K, and AKT was decreased (P<0.01, P<0.001, P<0.05). Compared with the Weizhong group, in the non-acupoint group and the inhibitor+Weizhong group, the body mass was decreased on the 7th and 14th days of intervention (P<0.001, P<0.01), the limb grip strength was decreased (P<0.001); the morphology of muscle cell was relatively poor, with generally irregular, there was mild collapse and atrophy in the vascular lumen, and mild edema in the endothelial cells; the levels of serum VEGF and eNOS were decreased (P<0.001); in psoas muscle, the protein expression of IGF-1 and IGF-1R, as well as the p-PI3K/PI3K and p-AKT/AKT values were decreased (P<0.01, P<0.001), the mRNA expression of IGF-1, IGF-1R, PI3K, and AKT was decreased (P<0.001, P<0.01, P<0.05). Compared with the Weizhong group, the PWT of the left hind foot was decreased in the non-acupoint group (P<0.001), and PWT of the left and right hind feet was decreased in the inhibitor+Weizhong group (P<0.001). CONCLUSION Acupuncture at "Weizhong" (BL40) promotes lumbar muscle repair in chronic low back pain, its mechanism may be related to the activation of the IGF-1/PI3K/AKT pathway, thereby improving the microcirculation.
Animals ; Insulin-Like Growth Factor I/genetics* ; Acupuncture Therapy ; Rats, Sprague-Dawley ; Rats ; Proto-Oncogene Proteins c-akt/genetics* ; Male ; Humans ; Muscle, Skeletal/metabolism* ; Signal Transduction ; Phosphatidylinositol 3-Kinases/genetics* ; Wounds, Nonpenetrating/metabolism* ; Acupuncture Points

The increasing prevalence of aging has led to a rising incidence of comorbidity of sarcopenia and obesity, posing significant burdens on socioeconomic and public health. Current research has systematically explored the pathogenesis of each condition; however, the mechanisms underlying their comorbidity remain unclear. This study reviews the current literature on sarcopenia and obesity in the aging population, focusing on their shared biological mechanisms, which include loss of autophagy, abnormal macrophage function, mitochondrial dysfunction, and reduced sex hormone secretion. It also identifies metabolic mechanisms such as insulin resistance, vitamin D metabolism abnormalities, dysregulation of iron metabolism, decreased levels of nicotinamide adenine dinucleotide, and gut microbiota imbalances. Additionally, this study also explores the important role of genetic factors, such as alleles and microRNAs, in the co-occurrence of sarcopenia and obesity. A better understanding of these mechanisms is vital for developing clinical interventions and preventive strategies.
Humans ; Sarcopenia/physiopathology* ; Obesity/physiopathology* ; Aging/physiology* ; Autophagy/physiology* ; Insulin Resistance ; Comorbidity ; Vitamin D/metabolism* ; Gonadal Steroid Hormones/metabolism* ; Gastrointestinal Microbiome ; Mitochondria ; MicroRNAs

This study aims to explore the role and mechanism of berberine in promoting the expression of aquaporin 4(AQP4) in astrocytes by regulating the expression of miR-383-5p in HepG2 cell-derived exosomes under insulin resistance(IR). The IR-HepG2 cell model was established with 1×10~(-6) mol·L~(-1) insulin. With metformin as the positive control, the safe concentrations of berberine and metformin were screened by cell counting kit-8(CCK-8) and lactate dehydrogenase(LDH) leakage assays, and the effect of berberine on the IR of HepG2 cells was evaluated by glucose consumption. NanoSight was used to measure the particle size and concentration of exosomes secreted by HepG2 cells in each group. HepG2 cell-derived exosomes in each group were incubated with astrocytes for 24 h, and the protein and mRNA levels of AQP4 in HA1800 cells were determined by Western blot and qRT-PCR, respectively. qRT-PCR was performed to determine the expression of miR-383-5p in HepG2 cell-derived exosomes and HA1800 cells after co-incubation. Western blotting was employed to determine the expression levels of miRNAs and proteins associated with exosome production and release in HepG2 cells. The results showed that 10 μmol·L~(-1) berberine and 1 mmol·L~(-1) metformin significantly alleviated the IR of HepG2 cells and reduced the concentration of exosomes in HepG2 cells. The exosomes of HepG2 cells treated with berberine and metformin significantly up-regulated the protein and mRNA levels of AQP4 in HA1800 cells. The mRNA level of miR-383-5p in HepG2 cell exosomes and HA1800 cells co-incubated with berberine and metformin decreased significantly. The intervention with berberine and metformin significantly down-regulated the expression of proteins associated with the production of miRNAs(Dicer, Drosha) as well as the production(Alix, Vps4A) and release(Rab35, VAMP3) of exosomes in IR-HepG2 cells. In conclusion, berberine can promote the expression of AQP4 in astrocytes by inhibiting the production and release of miR-383-5p in HepG2-derived exosomes under IR.
Humans ; MicroRNAs/metabolism* ; Berberine/pharmacology* ; Hep G2 Cells ; Exosomes/genetics* ; Aquaporin 4/metabolism* ; Insulin Resistance ; Astrocytes/drug effects*

This study explores the therapeutic differences and mechanisms of salt-processed Phellodendri Chinensis Cortex in improving insulin resistance(IR) based on network pharmacology, molecular docking, and cellular experiments. The components and intersection targets of Phellodendri Chinensis Cortex in improving IR were collected from databases, and a "drug-component-target-disease" network and protein-protein interaction(PPI) network were constructed to screen core components and targets. A total of 29 active components and 240 intersection targets were identified, of which 13 were core targets. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analyses were used to identify key signaling pathways, and molecular docking was performed to validate the binding activity between core components and targets. An IR model in HepG2 cells was induced using insulin combined with high glucose, and the effects of Phellodendri Chinensis Cortex before and after salt-processing on cell glucose consumption were evaluated. The expression of proteins related to the mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-kinase(PI3K)-protein kinase B(AKT) signaling pathways was detected by Western blot. The cellular experimental results showed that, compared with the model group, glucose consumption in the drug-treated groups was significantly increased(P<0.01), the phosphorylation level of extracellular regulated protein kinase(ERK) was decreased(P<0.05), the phosphorylation levels of PI3K and AKT were increased, and the expression of glucose transporter 4(GLUT4) was also upregulated(P<0.05). Furthermore, the effect of salt-processed Phellodendri Chinensis Cortex was better than that of raw Phellodendri Chinensis Cortex. The study demonstrates that Phellodendri Chinensis Cortex, both before and after salt-processing, improves IR by regulating the expression of related proteins in the MAPK and PI3K-AKT signaling pathways, with enhanced effects after salt-processing.
Humans ; Network Pharmacology ; Phellodendron/chemistry* ; Insulin Resistance ; Drugs, Chinese Herbal/chemistry* ; Hep G2 Cells ; Signal Transduction/drug effects* ; Molecular Docking Simulation ; Protein Interaction Maps/drug effects* ; Proto-Oncogene Proteins c-akt/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Glucose/metabolism*

Metabonomics and proteomics were employed to investigate the mechanism of Yuzhi Zhixue Granules in treating polycystic ovary syndrome with insulin resistance(PCOS-IR). The disease model was established by feeding a high-fat diet and gavage of letrozole solution and it was then treated with different doses of Yuzhi Zhixue Granules. The therapeutic effect of Yuzhi Zhixue Granules was evaluated based on the body mass, homeostasis model assessment of insulin resistance and insulin sensitivity index, serum levels of adipokines, and histopathological changes of rats. Metabolomics and proteomics were employed to find the action pathways of Yuzhi Zhixue Granules. The results showed that Yuzhi Zhixue Granules reduced the body mass, improved the insulin sensitivity and aromatase activity, improved the levels of leptin, adiponectin and other adipokines, and alleviated insulin resistance, histopathological changes, and metabolic disorders in PCOS-IR rats. Metabolomics results revealed 14 metabolites with altered levels in the ovarian tissue, which were closely related to glutathione metabolism and pyruvate metabolism. Proteomics results showed that the therapeutic effect of Yuzhi Zhixue Granules was mainly related to the adipokine, adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK), phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt), forkhead box protein O(FoxO), and mechanistic target of rapamycin(mTOR) signaling pathways. Western blot results showed that compared with the model group, Yuzhi Zhixue Granules treatment decreased the p-AMPK/AMPK and p-FoxO1/FoxO1 levels, increased the p-mTOR/mTOR level, and up-regulated the expression level of recombinant glucose transporter 4(GLUT4). Yuzhi Zhixue Granules can balance amino acid metabolism and pyruvate metabolism by regulating the AMPK/mTOR/FoxO/GLUT pathway to maintain the homeostasis of the ovarian environment and alleviate insulin resistance, thus treating PCOS-IR.
Animals ; Female ; Insulin Resistance ; Polycystic Ovary Syndrome/genetics* ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Metabolomics ; Proteomics ; Rats, Sprague-Dawley ; Humans ; Ovary/metabolism* ; Signal Transduction/drug effects*