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BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a major clinical and public health burden worldwide with no established pharmacological therapy. Changes in the intestinal flora and associated metabolite bile acids (BAs) have been described in NAFLD. Astragaloside IV (AS-IV) is a low drug permeability saponin with protective effects against multiple diseases. However, the specific mechanism underlying the involvement of AS-IV in the regulation of NAFLD is yet to be clarified. PURPOSE: This study aimed to investigate the effect of AS-IV on NAFLD and explore whether intestinal flora was involved. METHODS: The effect of AS-IV was evaluated on high-fat diet-fed mice. Real-time PCR, immunohistochemistry, immunofluorescence, and biochemical analyses were performed. 16S rRNA gene sequencing and UPLC-TQMS were used to determine the alterations in the intestinal flora and concentration of BAs. Fecal microbiota transplantation (FMT) and intestine-specific farnesoid X receptor (FXR) knockout were also performed. RESULTS: AS-IV treatment alleviated diet-induced metabolic impairments, particularly hepatic steatosis. These changes occurred in the setting of decreased intestinal bile salt hydrolase (BSH)-expressing flora. Further analysis showed that the reduced BSH activity increased intestinal tauro-ß-muricholic acid levels, an inhibitor of intestinal FXR. Inhibition of intestinal FXR signaling by AS-IV was accompanied by decreased expression of intestinal fibroblast growth factor 15 and subsequent hepatic FXR activation as well as increased glucagon-like peptide-1 and decreased ceramide production, all of which contribute to the inhibition of sterol regulatory element-binding protein-1c-mediated hepatic steatosis. Furthermore, intestine-specific Fxr knockout and FMT further demonstrated an FXR- and intestinal flora-dependent preventive effect of AS-IV on hepatic steatosis. CONCLUSION: These results show that the changes in intestinal flora and BAs serve an essential role in the remission of hepatic steatosis by AS-IV, thereby suggesting that AS-IV may be used as a prebiotic agent to provide viable treatment for NAFLD.
Assuntos
Microbioma Gastrointestinal , Hepatopatia Gordurosa não Alcoólica , Saponinas , Animais , Ácidos e Sais Biliares/metabolismo , Ceramidas/metabolismo , Ceramidas/farmacologia , Dieta Hiperlipídica/efeitos adversos , Fatores de Crescimento de Fibroblastos/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Intestinos , Fígado , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , RNA Ribossômico 16S , Receptores Citoplasmáticos e Nucleares/metabolismo , Saponinas/metabolismo , Saponinas/farmacologia , Esteróis/metabolismo , TriterpenosRESUMO
BACKGROUND: Lipophagy is an autophagic process, which delivers the intracellular lipid droplets to the lysosomes for degradation. Recent studies revealed that the impairment of lysosomal biogenesis and autophagic flux led to dysregulation of lipophagy in hepatocytes, which exacerbated the development of nonalcoholic fatty liver disease (NAFLD). Therefore, agents restoring autophagic flux and lipophagy in hepatocytes may have therapeutic potential against this increasingly prevalent disease. Phillygenin (PHI), a lignin extracted from Forsythia suspense, exerts hepatoprotective and anti-inflammatory effects. However, the effect of PHI on NAFLD remains unknown. PURPOSE: This study aimed to investigate the protective effect of PHI on NAFLD and elucidate the underlying mechanism. METHODS: The effects of PHI were examined in palmitate (PA)-stimulated AML12 cells and primary hepatocytes, as well as in NAFLD mice induced by a high-fat diet (HFD). We also used transcription factor EB (TFEB) knockdown hepatocytes and hepatocyte-specific TFEB knockout (TFEBΔhep) mice for mechanistic studies. In vivo and in vitro studies were performed using western blots, immunofluorescence techniques, and transmission electron microscopy. RESULTS: Our results indicated that autophagic flux and lysosome biogenesis in PA-stimulated hepatocytes were impaired. PHI alleviated lipid deposition by increasing lysosomal biogenesis and autophagic flux. It also stimulated the release of endoplasmic reticulum Ca2+ to activate calcineurin, which regulated TFEB dephosphorylation and nuclear translocation, and promoted lysosomal biogenesis. In addition, PHI blocked the NLRP3 inflammasome pathway and improved hepatocyte inflammation in an autophagy-dependent manner. Consistent with the in vitro results, PHI improved hepatic steatosis and inflammation in HFD mice, but these beneficial effects were eliminated in hepatocyte-specific TFEB knockout mice. CONCLUSION: Despite PHI has been reported to have anti-hepatic fibrosis effects, whether it has a hepatoprotective effects against NAFLD and the underlying molecular mechanism remain unclear. Herein, we found that PHI restored lipophagy and suppressed lipid accumulation and inflammation by regulating the Ca2+-calcineurin-TFEB axis in hepatocytes. Thus, PHI represents a therapeutic candidate for the treatment of NAFLD.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Autofagia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Calcineurina/metabolismo , Calcineurina/farmacologia , Calcineurina/uso terapêutico , Hepatócitos , Inflamação/metabolismo , Lignanas , Lipídeos , Lisossomos , Camundongos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismoRESUMO
Osteonecrosis of the femoral head (ONFH) is a chronic and irreversible disease that has a risk of eventually developing into a joint collapse and resulting in joint dysfunction. Quyushengxin capsule (QYSXC) is an effective and safe traditional Chinese medicine used in the treatment of ONFH. In this present study, an integrated approach was used to investigate the mechanism of QYSXC in the treatment of ONFH, which contained systems pharmacology, molecular docking, and chip experiment. In the systems pharmacology, target fishing, protein-protein interaction (PPI), Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis, and herbs-compounds-targets-pathways (H-C-T-P) network construction were performed to study the mechanism of QYSXC in the treatment of ONFH. The results showed that 15 key compounds, 8 key targets, and 8 key signaling pathways were found for QYSXC in the treatment with ONFH. Then, molecular docking was performed to further explore the interaction between some key compounds and key targets. After that, the chip experiment was performed to verify some target factors, including ICAM-1, IL-6, IL-1α, IL-1ß, IL-2, IL-4, IL-10, and TNF-α. The results of this work may provide a theoretical basis for further research on the molecular mechanism of QYSXC in the treatment of ONFH.
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ETHNOPHARMACOLOGICAL RELEVANCE: Quyu Shengxin capsule (QSC) is an herbal compound commonly used to treat blood stasis syndrome in China, and blood stasis syndrome is considered to be the root of cardiovascular diseases (CVD) in traditional Chinese medicine. However, the potential molecular mechanism of QSC is still unknown. AIM OF STUDY: To study the therapeutic effect of QSC on the abnormal proliferation of VSMCs induced by Ang-II, and to explore its possible mechanism of action. MATERIALS AND METHODS: Qualitative analysis and quality control of QSC through UPLC-MS/MS and UPLC. The rat thoracic aorta vascular smooth muscle cells (VSMCs) were cultured in vitro, and then stimulated with Angiotensin â ¡ (Ang-II) (10-7 mol/L) for 24 h to establish a cardiovascular cell model. The cells were then treated with different concentrations of QSC drug-containing serum or normal goat serum. MTT assay was used to detect the viability of VSMCs and abnormal cell proliferation. In order to analyze the possible signal transduction pathways, the content of various factors in the supernatant of VSMCs was screened and determined by means of the Luminex liquid suspension chip detection platform, and the phosphoprotein profile in VSMCs was screened by Phospho Explorer antibody array. RESULTS: Compared with the model group, serum cell viability and inflammatory factor levels with QSC were significantly decreased (P < 0.001). In addition, the expression levels of TGF-ß, VEGF, mTOR and JAK-STAT in the QSC-containing serum treatment group were significantly lower than those in the model group. QSC may regulate the pathological process of CVD by reducing the levels of inflammatory mediators and cytokines, and protecting VSMCs from the abnormal proliferation induced by Ang-II. CONCLUSION: QSC inhibits Ang-II-induced abnormal proliferation of VSMCs, which is related to the down-regulation of TGF-ß, VEGF, mTOR and JAK-STAT pathways.
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Medicamentos de Ervas Chinesas/farmacologia , Janus Quinases/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Fatores de Transcrição STAT/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Angiotensina II/toxicidade , Animais , Proliferação de Células/efeitos dos fármacos , Biologia Computacional , Regulação para Baixo/efeitos dos fármacos , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Molécula 1 de Adesão Intercelular/metabolismo , Masculino , Músculo Liso Vascular/citologia , Cultura Primária de Células , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
Chronic inflammation represents a long-term reaction of the body's immune system to noxious stimuli. Such a sustained inflammatory response sometimes results in lasting damage to healthy tissues and organs. In fact, chronic inflammation is implicated in the development and progression of various diseases, including cardiovascular diseases, respiratory diseases, metabolic diseases, neurodegenerative diseases, and even cancers. Targeting nonresolving inflammation thus provides new opportunities for treating relevant diseases. In this review, we will go over several chronic inflammation-associated diseases first with emphasis on the role of inflammation in their pathogenesis. Then, we will summarize a number of natural products that exhibit therapeutic effects against those diseases by acting on different markers in the inflammatory response. We envision that natural products will remain a rich resource for the discovery of new drugs treating diseases associated with chronic inflammation.
Assuntos
Anti-Inflamatórios/uso terapêutico , Produtos Biológicos/uso terapêutico , Inflamação/tratamento farmacológico , Neoplasias/tratamento farmacológico , Anti-Inflamatórios/química , Produtos Biológicos/química , Doenças Cardiovasculares/tratamento farmacológico , Doença Crônica , Humanos , Doenças Metabólicas/tratamento farmacológico , Doenças Neurodegenerativas/tratamento farmacológico , Transtornos Respiratórios/tratamento farmacológicoRESUMO
Oxidative stress plays an important role in diabetic nephropathy (DN), which is a diabetic complication. Ampelopsin (AMP) is a natural flavonoid that has been found to possess antidiabetic and antioxidative activities. However, the effect of AMP on DN remains unclear. In this study, we aimed to evaluate the protective effect of AMP on glomerular mesangial cells (MCs) exposed to high glucose (HG). We found that AMP improved HG-caused cell viability reduction in MCs. AMP significantly suppressed the intracellular ROS production and expression levels of ROS producing enzymes NADPH oxidase 2 (NOX2) and NOX4. Increased of NOX activity in HG-stimulated MCs was suppressed by AMP. Pretreatment with AMP inhibited extracellular matrix (ECM) accumulation in HG-stimulated MCs with decreased expression levels of fibronectin (FN) and collagen type IV (Col IV). Furthermore, AMP elevated the expression levels of nuclear Nrf2 and heme oxygenase-1 (HO-1), as well as increased the mRNA levels of Nrf2-driven genes NAD(P)H dehydrogenase quinone-1 (NQO-1) and HO-1 in HG-treated MCs. Knockdown of Nrf2 reversed the protective effects of AMP against HG-induced oxidative stress and EMC accumulation in MCs. In conclusion, these findings indicated that AMP protected MCs from HG-induced oxidative damage and ECM accumulation, which might be mediated by Nrf2/HO-1 pathway.
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Nefropatias Diabéticas/tratamento farmacológico , Matriz Extracelular/efeitos dos fármacos , Flavonoides/uso terapêutico , Glucose/metabolismo , Células Mesangiais/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Nefropatias Diabéticas/patologia , Flavonoides/farmacologia , Humanos , Fator 2 Relacionado a NF-E2/metabolismoRESUMO
Diabetic retinopathy, a leading cause of visual loss and blindness, is characterized by microvascular dysfunction. Hyperglycemia is considered the major pathogenic factor for diabetic retinopathy and is associated with increased oxidative stress in the retina. In this study, we investigated the potential protective effects of Panax notoginseng Saponins (PNS) in retinal capillary endothelial cells (RCECs) exposed to high glucose conditions. We found a pronounced increase in cell viability in rat RCECs incubated with both PNS and high glucose (30 mM) for 48 h or 72 h. The increased viability was accompanied by reduced intracellular hydrogen peroxide (H2O2) and superoxide (O2 (-)), decreased mitochondrial reactive oxygen species (ROS), and lowered malondialdehyde (MDA) levels. PNS also increased the activities of total superoxide dismutase (SOD), MnSOD, catalase (CAT), and glutathione peroxidase (GSH-PX). The glutathione (GSH) content also increased after PNS treatment. Furthermore, PNS reduced NADPH oxidase 4 (Nox4) expression. These results indicate that PNS exerts a protective effect against high glucose-induced injury in RCECs, which may be partially attributed to its antioxidative function.
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Baicalin is an important active component of the medicinal herb Scutellaria baicalensis Georgi and has shown a variety of pharmacological actions. The present study aimed to evaluate the neuroprotective effects of baicalin against diabetesassociated cognitive deficits (DACD) in rats and to elucidate the potential molecular mechanisms of action. A rat model of diabetes mellitus was prepared by intraperitoneal injection of streptozotocin. After the successful establishment of the diabetic rat model, baicalin (50, 100 and 200 mg/kg) or vehicle was administrated for seven weeks. Learning and memory function were assessed using the Morris water maze test. At the end of the experiment, the activities of acetylcholinesterase (AChE) and choline acetylase (ChAT) were determined using commercial kits. Furthermore, the expression of proteins involved in mitogenactivated protein kinase (MAPK) cascades [extracellular signalregulated kinase (ERK), cJun Nterminal kinase (JNK) and p38], brainderived neurotrophic factor (BDNF) and apoptosisassociated proteins [caspase3, B-cell lymphoma 2 (Bcl2) and Bcl-2-associated X protein (Bax)] were detected by western blot analysis. Caspase3 activity was also analyzed using a commercial kit. The results demonstrated that diabetic rats exhibited decreases in body weight, decreases in the percentage of time spent in the target quadrant and the number of times of crossing the platform in the water maze test, as well as decreases in neuronal survival, ChAT, phosphorylated (p)ERK, BDNF and Bcl2. Furthermore, diabetic rats showed increases in escape latency and mean path length in the water maze test, increases in the levels of hippocampal AChE, pJNK, pp38, caspase3 and Bax as well as plasma glucose. However, in diabetic rats treated with baicalin, all of the abovementioned observations were obviously reversed. The findings suggested that baicalin exerts neuroprotective effects against DACD via modulation of MAPK cascades, BDNF and apoptosis.
Assuntos
Apoptose/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Transtornos Cognitivos/tratamento farmacológico , Flavonoides/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Acetilcolinesterase/metabolismo , Animais , Glicemia/metabolismo , Caspase 3/metabolismo , Colina O-Acetiltransferase/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Wistar , Estreptozocina , Proteína X Associada a bcl-2/metabolismoRESUMO
The aim of this study was to investigate the acute and sub-chronic toxicity of extract of Thunberg Fritillary Bulb. For the acute toxicity tests, graded doses of the extract were administered orally to mice. The animals were observed for toxic symptoms and mortality daily for 14days. In the sub-chronic toxicity study, rats were orally administered the extract at doses of 1 and 3mg/kg body weight (BW) for 26weeks. After 26weeks, the rats were sacrificed for hematological, biochemical and histological examination. In the acute toxicity tests, the estimated median lethal dosage (LD50) was 52.2mg/kg body weight in the mice. In the sub-chronic toxicity tests, a dose of 1mg/kg body weight presented no toxicity. Above the 1mg/kg dose, the main adverse signs observed in male rats were body or head tremor and spontaneous motor activity reduction. There were no other significant changes observed in hematology, blood biochemistry, organ weight and organ histology. The overall findings of this study indicate that the extract of Thunberg Fritillary Bulb is non-toxic up to 1mg/kg body weight, which can be considered a safe application dose.
Assuntos
Fritillaria , Extratos Vegetais/toxicidade , Animais , Feminino , Dose Letal Mediana , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Síndromes Neurotóxicas/etiologia , Raízes de Plantas , Ratos Sprague-Dawley , Testes de Toxicidade Aguda , Testes de Toxicidade Subcrônica , Tremor/induzido quimicamenteRESUMO
Translation initiation plays a critical role in the regulation of cell growth and tumorigenesis. We report here that inhibiting translation initiation through induction of eIF2α phosphorylation by small-molecular-weight compounds restricts the availability of the eIF2.GTP.Met-tRNAi ternary complex and abrogates the proliferation of cancer cells in vitro and tumor growth in vivo. Restricting the availability of the ternary complex preferentially down-regulates the expression of growth-promoting proteins and up-regulates the expression of ER stress response genes in cancer cells as well as in tumors excised from either animal models of human cancer or cancer patients. These findings provide the first direct evidence for translational control of gene-specific expression by small molecules in vivo and indicate that translation initiation factors are bona fide targets for development of mechanism-specific anti-cancer agents.
Assuntos
Antineoplásicos/farmacologia , Cromanos/farmacologia , Clotrimazol/farmacologia , Ácido Eicosapentaenoico/farmacologia , Iniciação Traducional da Cadeia Peptídica/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Animais , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclina D1/biossíntese , Modelos Animais de Doenças , Fator de Iniciação 2 em Eucariotos/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos DBA , Fosforilação/efeitos dos fármacos , Biossíntese de Proteínas , Distribuição Aleatória , Troglitazona , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PURPOSE: To develop a noninvasive MRI method for determining the germination and infection of tumor-homing bacteria in bacteriolytic cancer therapy using endogenous CEST contrast. METHODS: The CEST parameters of the anaerobic gram-positive bacterium Clostridium novyi-NT (C. novyi-NT) were first characterized in vitro, then used to detect C. novyi-NT germination and infection in subcutaneous CT26 colorectal tumor-bearing mice (n = 6) after injection of 300 million bacterial spores. Lipopolysacharide (LPS) injected mice were used to exclude that the changes of CEST MRI were due to inflammation. RESULTS: CEST contrast was observed over a broad frequency range for bacterial suspensions in vitro, with the maximum contrast around 2.6 ppm from the water resonance. No signal could be detected for bacterial spores, demonstrating the specificity for germination. In vivo, a significant elevation of CEST contrast was identified in C. novyi-NT infected tumors as compared to those before bacterial germination and infection (P < 0.05; n = 6). No significant change was observed in tumors with LPS-induced sterile inflammation (P > 0.05; n = 4). CONCLUSION: Endogenous bacterial CEST contrast (bacCEST) can be used to monitor the germination and proliferation of the therapeutic bacterium C. novyi-NT without a need for exogenous cell labeling probes.
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Infecções por Clostridium/patologia , Clostridium/isolamento & purificação , Clostridium/fisiologia , Neoplasias Colorretais/terapia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Animais , Terapia Biológica/métodos , Linhagem Celular Tumoral , Infecções por Clostridium/microbiologia , Neoplasias Colorretais/microbiologia , Neoplasias Colorretais/patologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To investigate the inhibitory effect of Yifei Huoxue Granule (, YFHXG) on the hypoxia-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and its mechanism of decreasing pulmonary arterial pressure. METHODS: Twenty male Sprague-Dawley (SD) rats were randomly divided into four groups: saline, and 0.66, 3.30 and 16.50 g/kg of YFHXG groups, the saline and different concentrations of YFHXG were given twice daily for 7 days, respectively. Serum-pharmacology method was used in the preparation of YFHXG serum. Tissue block anchorage was employed in the primary culture of rat PASMCs. The PASMCs were randomly divided into normoxia group, hypoxia group, and hypoxia+YFHXG group (0.66, 3.30 and 16.50 g/kg doses of YFHXG-treated serum groups, exposed to hypoxic condition). PASMCs in normoxia and hypoxia group were cultured with saline serum, hypoxia+YFHXG groups were cultured with different concentrations of YFHXG serum. Cell viability was assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle was analyzed using flow cytometry. In addition, hypoxia inducible factor-1-alpha (HIF-1α) protein expression was evaluated by immunocytochemistry analysis, the concentration of intracellular reactive oxygen species (ROS) and Ca(2+) were determined by laser scanning confocal microscopy (LSCM). RESULTS: MTT assay and flow cytometry showed that hypoxia could directly activate the proliferation of PASMCs, while YFHXG dose-dependently inhibited hypoxia-induced proliferation of rat PASMCs. Immunocytochemistry showed that hypoxia enhanced HIF-1α protein expression, and LSCM showed that hypoxia significantly increased intracellular ROS and Ca(2+), while YFHXG decreased the expression of HIF- 1α and attenuated the hypoxia-induced increase in intracellular concentration of ROS and Ca(2+). CONCLUSIONS: YFHXG could inhibit hypoxia-induced proliferation of rat PASMCs, which may decrease pulmonary arterial pressure and vascular remodeling. The anti-hypoxia effect of YFHXG may be explained by its regulation of HIF-1α expression and of the levels of intracellular ROS and Ca(2+).
Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/efeitos dos fármacos , Artéria Pulmonar/citologia , Animais , Cálcio/metabolismo , Ciclo Celular/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Masculino , Miócitos de Músculo Liso/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismoRESUMO
HSD-3.8 cDNA (accession number AF311312) encodes a human sperm component. A 0.7 kb fragment (HSD-0.7) containing three immunological epitopes of HSD-3.8 cDNA was prepared and expressed in E. coli. Immunization of female rats with the recombinant HSD-0.7 proteins induced infertility. A cDNA fragment encoding the C-terminal 144 amino acids of human G-protein beta l subunit (Gbeta1-C144) was screened by yeast two-hybrid, when HSD-0.7 segment was used as a bait. Recombinant His6-tagged-Gbeta1-C144 protein was expressed in E. coli BL21 and Anti-Gbeta1 serum was raised with purified Gbeta1-C144. HA-tagged HSD-0.7 and FLAG-tagged Gbeta1 plasmids were constructed and co-transfected into human embryonal kidney 293 cells. Two proteins were localized at superimposable sites in the cytoplasm, and they formed a complex when 500 micromol/L GDP existed. Overexpression of HSD-0.7 activated the G-protein-mediated extracellular signal-regulated kinases (ERK1/2); however, the truncated fragments of HSD-0.7, which lacked either TPR domain or P-loop, lost the ability to activate the ERK1/2 pathway. Further study revealed that the activation of ERK1/2 was protein kinase C (PKC) rather than Ras dependent. These results provide evidence that HSD-3.8 present in spermatocytes and sperm may participate in spermatogenesis and fertilization process by activating the PKC-dependent ERK1/2 signal transduction pathway.