OBJECTIVE: To observe the effects of the "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture on key regulatory factors during mitochondrial apoptosis of testicular tissue in asthenozoospermia mice, and explore the potential mechanism of the protective effect of acupuncture on reproductive function. METHODS: Thirty C57BL/6 male mice were randomly divided into a blank group, a model group and an acupuncture group, 10 mice in each group. In the model and the acupuncture groups, the intraperitoneal injection of cyclophosphamide (30 mg•kg^-1•d^-1) was delivered for 7 days to prepare the asthenozoospermia model. After the success of modeling, the modeled mice in the acupuncture group were intervened with "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture, once daily and the needles were retained for 20 min. The duration of the intervention was 2 weeks. The general condition of each mouse was observed, and the body mass was recorded before modeling, after modeling and after intervention completion. After intervention, the testicular mass was recorded and the weight coefficient was calculated, and the mouse sperm quality was examined; the serum contents of testosterone (T), follicle stimulating hormone (FSH) and luteinizing hormone (LH) were detected using ELISA, the morphology of testicular tissue was observed using HE, the mitochondrial ultra-microstructure of testicular tissue was observed under transmission electrone microscopy, the mitochondrial membrane potential level of testicular tissue was detected using JC-1 staining, the positive rate of apoptosis cell of testicular tissue was observed using TUNEL; and the mRNA and protein expression of b-cell lymphocytoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), cytochrome c (Cyt C), apoptotic protease-activating factor1 (Apaf-1), Caspase-9 and Caspase-3 of testicular tissue was detected using real-time quantitative fluorescence PCR and Western blot methods separately; and the positive expression of Cleaved Caspase-3 of the testicular tissue was detected using immunohistochemistry. RESULTS: Compared with the blank group, the mice were in listless spirits, had shaggy hairs, the reduced appetite and movement, and weight loss in the model group (P<0.01); the testicular mass and the weight coefficient decreased (P<0.01); the total number of sperms, sperm motility, and sperm viability were declined (P<0.01); while the levels of serum T, FSH, and LH were dropped (P<0.01). The morphology of seminiferous tubules in testicular tissue was abnormal, the number of spermatogenic cells and the number of mitochondria decreased, the inner mitochondrial crest was fractured and lost, and vacuoles appeared. The level of mitochondrial membrane potential was reduced (P<0.01); and the positive rate of apoptosis cell in testicular tissue increased (P<0.01). The mRNA and protein expression of Bax, Cyt C, Apaf-1, Caspase-9 and Caspase-3 was elevated (P<0.01, P<0.05), the mRNA and protein expression of Bcl-2 was dropped (P<0.01), and the average absorbance value of Cleaved Caspase-3 increased (P<0.01). When compared with the model group, in the acupuncture group, the general condition of mice was improved, the testicular mass and the weight coefficient elevated (P<0.01); the total number of sperms, sperm motility, and sperm viability increased (P<0.01); while the levels of serum T, FSH, and LH rose (P<0.01). The pathological morphology of testicular tissue and the inner mitochondrial ultra-microstructure were ameliorated, the level of mitochondrial membrane potential was elevated (P<0.01); the positive rate of apoptosis cell was reduced (P<0.01). The mRNA and protein expression of Bax, Cyt C, Apaf-1, Caspase-9 and Caspase-3 was dropped (P<0.01, P<0.05), the mRNA and protein expression of Bcl-2 elevated (P<0.05), and the average absorbance value of Cleaved Caspase-3 declined (P<0.01). CONCLUSION "Zhibian" (BL54)-toward- "Shuidao" (ST28) acupuncture may ameliorate mouse reproductive function by inhibiting mitochondrial apoptosis pathway, alleviating testicular tissue damage in the asthenospermia mice induced by cyclophosphamide.
Animals ; Male ; Mice ; Apoptosis ; Acupuncture Therapy ; Mitochondria/metabolism* ; Asthenozoospermia/genetics* ; Humans ; Testis/metabolism* ; Mice, Inbred C57BL ; Spermatozoa/metabolism* ; Acupuncture Points ; Sperm Motility ; Testosterone/blood* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Caspase 3/genetics* ; Follicle Stimulating Hormone/blood* ; Reproduction ; Cytochromes c/genetics* ; bcl-2-Associated X Protein/genetics* ; Apoptotic Protease-Activating Factor 1/genetics*

This study investigated the effects of Rehmanniae Radix Praeparata on striatal neuronal apoptosis in rats with attention deficit hyperactivity disorder(ADHD) based on the B-cell lymphoma-2(Bcl-2)/Bcl-2-associated X protein(Bax)/caspase-3 signaling pathway. Twenty-four 3-week-old male spontaneously hypertensive rats(SHR) were randomly divided into a model group, a methylphenidate group(2 mg·kg~(-1)·d~(-1)), and a Rehmanniae Radix Praeparata group(2.4 mg·kg~(-1)·d~(-1)). Age-matched male Wistar Kyoto(WKY) rats were used as the normal control group, with 8 rats in each group. The rats were administered by gavage for 28 days. Body weight and food intake were recorded for each group. The open field test and elevated plus maze test were used to assess hyperactivity and impulsive behaviors. Nissl staining was used to detect changes in striatal neurons and Nissl bodies. Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) fluorescence staining was used to detect striatal cell apoptosis. Western blot was employed to detect the expression levels of Bcl-2, Bax, and caspase-3 proteins in the striatum. The results showed that compared with the model group, Rehmanniae Radix Praeparata significantly reduced the total movement distance, average movement speed, and central area residence time in the open field test, and significantly reduced the ratio of open arm entries, open arm stay time, and head dipping in the elevated plus maze test. Furthermore, it increased the number of Nissl bodies in striatal neurons, significantly downregulated the apoptosis index, significantly increased Bcl-2 protein expression and the Bcl-2/Bax ratio, and reduced Bax and caspase-3 protein expression. In conclusion, Rehmanniae Radix Praeparata can reduce hyperactivity and impulsive behaviors in ADHD rats. Its mechanism may be related to the regulation of the Bcl-2/Bax/caspase-3 signaling pathway in the striatum, enhancing the anti-apoptotic capacity of striatal neurons.
Animals ; Male ; Apoptosis/drug effects* ; Rats ; Drugs, Chinese Herbal/administration & dosage* ; Caspase 3/genetics* ; Proto-Oncogene Proteins c-bcl-2/genetics* ; bcl-2-Associated X Protein/genetics* ; Rehmannia/chemistry* ; Attention Deficit Disorder with Hyperactivity/physiopathology* ; Signal Transduction/drug effects* ; Neurons/cytology* ; Rats, Inbred SHR ; Rats, Inbred WKY ; Humans ; Corpus Striatum/cytology* ; Plant Extracts

This study aims to elucidate the role and mechanism of clematichinenoside AR(CAR) in protecting bone marrow mesenchymal stem cells(BMSCs) from hypoxia-induced apoptosis. BMSCs were isolated by the bone fragment method and identified by flow cytometry. Cells were cultured under normal conditions(37℃, 5% CO_2) and hypoxic conditions(37℃, 90% N_2, 5% CO_2) and treated with CAR. The BMSCs were classified into eight groups: control(normal conditions), CAR(normal conditions + CAR), hypoxia 24 h, hypoxia 24 h + CAR, hypoxia 48 h, hypoxia 48 h + CAR, hypoxia 72 h, and hypoxia 72 h + CAR. The cell counting kit-8(CCK-8) assay and terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL) were employed to measure cell proliferation and apoptosis, respectively. The number of mitochondria and mitochondrial membrane potential were measured by MitoTracker®Red CM-H2XRo staining and JC-1 staining, respectively. The level of reactive oxygen species(ROS) was measured with the DCFH-DA fluorescence probe. The protein levels of B-cell lymphoma-2 associated X protein(BAX), caspase-3, and optic atrophy 1(OPA1) were determined by Western blot. The results demonstrated that CAR significantly increased cell proliferation. Compared with the control group, the hypoxia groups showed increased apoptosis rates, reduced mitochondria, elevated ROS levels, decreased mitochondrial membrane potential, upregulated expression of BAX and caspase-3, and downregulated expression of OPA1. In comparison to the corresponding hypoxia groups, CAR intervention significantly decreased the apoptosis rate, increased mitochondria, reduced ROS levels, elevated mitochondrial membrane potential, downregulated the expression of BAX and caspase-3, and upregulated the expression of OPA1. Therefore, it can be concluded that CAR may exert an anti-apoptotic effect on BMSCs under hypoxic conditions by regulating OPA1 to maintain mitochondrial homeostasis.
Mesenchymal Stem Cells/metabolism* ; Apoptosis/drug effects* ; Mitochondria/metabolism* ; Animals ; Rats ; Cell Hypoxia/drug effects* ; Homeostasis/drug effects* ; Reactive Oxygen Species/metabolism* ; Rats, Sprague-Dawley ; Membrane Potential, Mitochondrial/drug effects* ; Saponins/pharmacology* ; Caspase 3/genetics* ; Male ; bcl-2-Associated X Protein/genetics* ; Bone Marrow Cells/metabolism* ; Cell Proliferation/drug effects* ; Protective Agents/pharmacology* ; Cells, Cultured

This study integrates metabolomics and transcriptomics to explore the immediate effects of Angong Niuhuang Pills(ANP) in intervening traumatic brain injury(TBI) in rats. A TBI model was successfully established in rats using the optimized Feeney free-fall impact technique. Rats were randomly divided into sham operation(sham) group, model(Mod) group, positive drug(piracetam) group, ANP low-dose(ANP-L) group, and ANP high-dose(ANP-H) group according to a random number table. Nissl staining and immunofluorescence were used to count the number of Nissl bodies and detect B-cell lymphoma-2(Bcl-2) gene, caspase-3, and tumor protein 53(TP53) expression in brain tissue, and enzyme-linked immunosorbent assay(ELISA) was used to measure prostaglandin-endoperoxide synthase 2(PTGS2) level in rat brain tissue. Metabolomics and transcriptomics analyses were conducted for brain tissue from sham, Mod, and ANP-H groups. Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were carried out to indicate the mechanisms of ANP in the intervention of TBI. Integrative metabolomics and transcriptomics analysis revealed the metabolic pathways involved in ANP's intervention in TBI. The results showed that ANP significantly increased the number of Nissl bodies in TBI rat brain tissue, upregulated Bcl-2 expression, and downregulated the levels of caspase-3, TP53, and PTGS2. Compared to the Mod group, the ANP-H group significantly upregulated 12 differential metabolites(DMs) and downregulated 25 DMs. Five key metabolic pathways were identified, including glycerophospholipid metabolism, pyrimidine metabolism, glycine, threonine, and serine metabolism, arginine and proline metabolism, and D-amino acid metabolism. Transcriptomics identified 730 upregulated and 612 downregulated differentially expressed genes(DEGs). Enrichment analysis highlighted that biological functions related to inflammatory responses and apoptotic processes, and key signaling pathways, including phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt) and mitogen-activated protein kinase(MAPK) were significantly enriched. The data of transcriptomics and metabolomics pinpointed three key metabolic pathways, i.e., glycerophospholipid metabolism, pyrimidine metabolism, and glycine, threonine, and serine metabolism.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Brain Injuries, Traumatic/metabolism* ; Male ; Metabolomics ; Rats, Sprague-Dawley ; Transcriptome/drug effects* ; Cyclooxygenase 2/genetics* ; Brain/metabolism* ; Caspase 3/genetics* ; Humans ; Tumor Suppressor Protein p53/genetics*

This study aims to explore whether Albiziae Cortex-Tribuli Fructus can exert an anti-hepatic fibrosis effect by regulating the nuclear factor E2-related factor 2(Nrf2)/NOD-like receptor protein 3(NLRP3)/cysteine protease-1(caspase-1) pathway and analyze its potential mechanism. In the in vivo experiment, a mouse model of hepatic fibrosis was established by subcutaneous injection of carbon tetrachloride. The levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), collagen type Ⅳ(ColⅣ), laminin(LN), procollagen type Ⅲ(PCⅢ), and hyaluronic acid(HA) in the serum of mice were measured using a fully automated biochemical analyzer and ELISA. Hematoxylin and eosin(HE) and Masson staining were used to observe inflammation and collagen fiber deposition in the liver tissue. Western blot and RT-qPCR were employed to detect the protein and mRNA expression of collagen type Ⅰ(collagen Ⅰ), α-smooth muscle actin(α-SMA), Nrf2, NLRP3, gasdermin D(GSDMD), and caspase-1 in the hepatic tissue. In the in vitro experiment, human hepatic stellate cells(HSC-LX2) were pretreated with Nrf2 agonist or inhibitor, followed by the addition of blank serum, AngⅡ + blank serum, and AngⅡ + Albiziae Cortex-Tribuli Fructus-containing serum for intervention. Western blot was used to detect the protein expression of Nrf2, NLRP3, GSDMD, caspase-1, α-SMA, GSDMD-N, and apoptosis-associated speck-like protein(ASC) in cells. DCFH-DA fluorescence probe was used to detect the cellular ROS levels. The results from the in vivo experiment showed that, compared with the model group, Albiziae Cortex-Tribuli Fructus significantly reduced the serum levels of AST, ALT, ColⅣ, LN, PCⅢ, and HA, reduced the infiltration of inflammatory cells and collagen fiber deposition in the liver tissue, significantly upregulated the protein and mRNA expression of Nrf2 in the liver tissue, and significantly downregulated the protein and mRNA expression of collagen I, α-SMA, NLRP3, GSDMD, and caspase-1 in the liver tissue. The results from the in vitro experiment showed that Nrf2 activation decreased the protein expression of NLRP3, GSDMD, caspase-1, α-SMA, GSDMD-N, ASC, and ROS levels in HSC-LX2, while Nrf2 inhibition showed the opposite trend. Furthermore, Albiziae Cortex-Tribuli Fructus-containing serum directly decreased the expression of the above proteins and ROS levels. In conclusion, Albiziae Cortex-Tribuli Fructus can effectively improve hepatic fibrosis, and its mechanism of action may involve inhibiting pyroptosis through the regulation of the Nrf2/NLRP3/caspase-1 pathway.
Animals ; NF-E2-Related Factor 2/genetics* ; Liver Cirrhosis/genetics* ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Caspase 1/genetics* ; Male ; NLR Family, Pyrin Domain-Containing 3 Protein/genetics* ; Signal Transduction/drug effects* ; Humans ; Liver/metabolism* ; Mice, Inbred C57BL ; Plant Extracts ; Tribulus

Objective To explore the mechanism of lncRNA-BC200 (BC200) targeting the ubiquitination of Beta-site APP cleaving enzyme 1 (BACE1) and regulating the repair of nerve cell injury. Methods Mouse hippocampal neuron cell line HT22 was divided into four groups: control group, oxygen-glucose deprivation/reoxygenation(OGD/R) group, OGD/R+si-NC group and OGD/R+si-BC200 group. In order to further explore the relationship between BC200 and BACE1, HT22 cells were divided into four groups: OGD/R group, OGD/R+si-BC200 group, OGD/R+si-BC200+NC group and OGD/R+si-BC200+ BACE1 group. Twenty male C57BL/6J mice were randomly assigned to the following four groups: control group, middle cerebral artery occlusion (MCAO) group, MCAO+si-BC200 group and MCAO+si-BC200+BACE1 group. The mRNA expression levels of BC200 and BACE1 in cells were measured by real-time quantitative reverse transcription polymerase chain reaction. The expressions of c-caspase-3, B-cell lymphoma 2 (Bcl2), Bcl2 associated X protein(BAX) and BACE1 were detected by western blot, and the apoptotic cells were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test. Results Compared with the control group, the activity of HT22 cells in OGD/R group decreased significantly, and the percentage of apoptotic cells increased significantly. Compared with OGD/R+si-NC group, the activity of HT22 cells in OGD/R+si-BC200 group increased significantly, and the percentage of apoptotic cells decreased significantly. Compared with the control group, the expression of BACE1 protein in HT22 cells in OGD/R group was significantly enhanced. Compared with OGD/R+si-NC group, the expression of BACE1 protein in HT22 cells in OGD/R+si-BC200 group decreased significantly. It was observed that after OGD/R treatment, the ubiquitination level of BACE1 decreased significantly and the expression of BACE1 protein increased significantly. After transfection with si-BC200, the ubiquitination level of BACE1 protein increased significantly, while the expression of BACE1 protein decreased significantly. Compared with OGD/R+si-BC200+NC group, the percentage of apoptotic cells, the expression of c-caspase-3 and Bax protein in HT22 cells in OGD/R+si-BC200+BACE1 group increased significantly, and the expression of Bcl2 protein decreased significantly. Compared with the control group, the number of cerebral infarction areas and TUNEL positive cells in MCAO group increased significantly, and the survival number of neurons decreased significantly. Compared with the MCAO group, the number of cerebral infarction areas and TUNEL positive cells in MCAO+si-BC200 group decreased significantly, and the survival number of neurons increased significantly, while the addition of BACE1 reversed the improvement of si-BC200 transfection. Conclusion The combination of BC200 and BACE1 inhibit the ubiquitination of BACE1, and participate in mediating the expression enhancement of BACE1 induced by OGD/R. Specific blocking of BC200/BACE1 axis may be a potential therapeutic target to protect neurons from apoptosis induced by cerebral ischemia/reperfusion.
Animals ; Amyloid Precursor Protein Secretases/genetics* ; RNA, Long Noncoding/physiology* ; Aspartic Acid Endopeptidases/genetics* ; Male ; Neurons/pathology* ; Mice ; Mice, Inbred C57BL ; Apoptosis/genetics* ; Ubiquitination ; Cell Line ; Hippocampus/metabolism* ; bcl-2-Associated X Protein/genetics* ; Caspase 3/genetics* ; Infarction, Middle Cerebral Artery/metabolism*

OBJECTIVE: To study the expression of SPOP in patients with acute myeloid leukemia (AML) and its effect on proliferation, apoptosis and cycle of AML cells. METHODS: RT-qPCR was used to detect the expression of SPOP mRNA in bone marrow samples of patients with newly diagnosed AML and normal controls. The stable overexpression of SPOP in AML cell lines THP-1 and U937 were constructed by liposome transfection. The effect of SPOP on cell proliferation was detected by CCK-8, and the effect of SPOP on apoptosis and cell cycle was detected by flow cytometry. The expressions of anti-apoptotic protein Bcl-2 and apoptotic protein Bax, Caspase3 were detected by Western blot. RESULTS: The median expression level of SPOP mRNA in normal control group was 0.993 1(0.6303, 1.433), while that in AML group was 0.522 1(0.242 2, 0.723 7). The expression level of SPOP in AML group was significantly lower than that in normal control group ( P < 0.001). After the overexpression of SPOP, the proportion of apoptotic cells in the U937 overexpression group and THP-1 overexpression group was 10.9%±0.3% and 4.6%±015%, which were higher than 8.9%±0.3% and 3.0%±0.30% in the Empty Vector group, respectively (both P < 0.05). The expression of Caspase3 in U937 overexpression group and THP-1 overexpression group was 1.154±0.086 and 1.2±0.077, which were higher than 1 in Empty Vector group, respectively (both P < 0.05). The ratio of Bax/Bcl-2 in U937 overexpression group and THP-1 overexpression group was 1.328±0.057 and 1.669±0.15, which were higher than 1 in Empty Vector group, respectively (both P < 0.05). In the cell proliferation experiment, the number of cells in the U937 overexpression group and THP-1 overexpression group were both slightly lower than those in the Empty Vector group, but the differences were not statistically significant (P >0.05). In the cell cycle experiment, the proportion of G₁ cells in the U937 overexpression group and THP-1 overexpression group were both slightly higher than those in the Empty Vector group, but the differences were not statistically significant (P >0.05). CONCLUSION SPOP can promote the apoptosis of leukemic cells, and its mechanism may be related to down-regulation of Bcl-2 expression and up-regulation of Bax and Caspase3 expression.
Humans ; Leukemia, Myeloid, Acute/pathology* ; Apoptosis ; Repressor Proteins/genetics* ; Cell Proliferation ; Nuclear Proteins/genetics* ; Cell Cycle ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Caspase 3/metabolism* ; bcl-2-Associated X Protein/metabolism* ; U937 Cells ; Cell Line, Tumor ; RNA, Messenger/genetics*

OBJECTIVES: To explore the mechanism by which histone deacetylase 1 (HDAC1) regulates steroid-induced apoptosis of mouse osteocyte-like MLO-Y4 cells. METHODS: MLY-O4 cells were treated with 400 nmol/L trichostatin A (TSA) or 1 mmol/L dexamethasone for 24 h or transfected with a HDAC1-overexpressing vector prior to TSA or dexamethasone treatment. The changes in the expressions of HDAC1, SP1, cleaved caspase-3 and Bax, SP1 acetylation level, cell proliferation, and cell apoptosis were examined. The interaction between HDAC1 and SP1 was determined with immunoprecipitation assay and Western blotting. RESULTS: Treatment with dexamethasone significantly increased cell apoptosis, enhanced the expressions of cleaved caspase-3 and Bax, reduced HDAC1 expression, and suppressed proliferation of MLO-Y4 cells. Both TSA and dexamethasone obviously increased SP1 acetylation level and the expression of SP1 in MLO-Y4 cells. HDAC1 overexpression in the cells significantly attenuated the effect of TSA and dexamethasone, promoted cell proliferation, lowered the expressions of SP1, cleaved caspase-3 and Bax, and inhibited dexamethasone-induced cell apoptosis. Immunoprecipitation assay and Western blotting demonstrated the interaction between HDAC1 and SP1 in the cells. CONCLUSIONS HDAC1 inhibits dexamethasone-induced apoptosis and promotes proliferation of cultured mouse osteocytes by suppressing SP1 expression via promoting its deacetylation.
Animals ; Apoptosis/drug effects* ; Mice ; Histone Deacetylase 1/genetics* ; Osteocytes/drug effects* ; Sp1 Transcription Factor/metabolism* ; Acetylation ; Dexamethasone/pharmacology* ; Cell Proliferation/drug effects* ; Caspase 3/metabolism* ; Cell Line ; Hydroxamic Acids/pharmacology* ; bcl-2-Associated X Protein/metabolism*

This study aimed to investigate the effect of aucubin(AU) on injury of nucleus pulposus cells and extracellular matrix(ECM) degradation and its mechanism. The nucleus pulposus cell injury model was established by interleukin-1β(IL-1β) and treated with AU or phosphatidylinositol 3-kinase(PI3K) inhibitor LY294002. CCK-8 experiment was conducted to test cell proliferation. EdU staining method was employed to detect cell injury. Flow cytometry was used to detect cell apoptosis. Western blot was used to detect protein levels of cleaved-caspase-3, B-cell lymphoma(Bcl-2), Bcl-2 associated X protein(Bax), type Ⅱ collagen(collagen Ⅱ), aggregation proteoglycans(aggrecan), PI3K, and mammalian target of rapamycin(mTOR). qPCR was used to detect the rRNA level of 5S, 18S, and 28S. Ethynyluridine was used to label nascent RNA. The results showed that IL-1β could significantly cause injury of nucleus pulposus cells and increase the apoptosis rate of nucleus pulposus cells and the expression of apoptosis protein cleaved-caspase-3 and Bax. At the same time, IL-1β down-regulated the expression of anti-apoptotic protein Bcl-2 and collagen Ⅱ and aggrecan, the main components of ECM. On this basis, AU intervention could improve the injury of nucleus pulposus cells, reduce the apoptosis of nucleus pulposus cells and the expression of cleaved-caspase-3 and Bax, and increase the expression of Bcl-2, collagen Ⅱ, and aggrecan. Compared with IL-1β, AU could up-regulate the phosphorylation level of PI3K and mTOR, and LY294002 could reverse the injury of nucleus pulposus cells and improve ECM degradation induced by AU. In addition, AU also could save lowered rRNA levels of 5S, 18S, and 28S induced by IL-1β and improve RNA synthesis. PI3K inhibitor LY294002 intervention could reduce the promoting effect of AU on ribosome biogenesis. The above results suggest that AU can improve the injury of nucleus pulposus cells and ECM degradation, and its mechanism of action is related to its activation of the PI3K/mTOR pathway to promote ribosome biogenesis.
Nucleus Pulposus/cytology* ; Extracellular Matrix/drug effects* ; Animals ; Iridoid Glucosides/pharmacology* ; Apoptosis/drug effects* ; Interleukin-1beta/metabolism* ; Phosphatidylinositol 3-Kinases/genetics* ; Rats ; Cell Proliferation/drug effects* ; TOR Serine-Threonine Kinases/genetics* ; Rats, Sprague-Dawley ; Humans ; Signal Transduction/drug effects* ; Caspase 3/genetics* ; Proto-Oncogene Proteins c-bcl-2/genetics*

Caspase-2, a highly conserved member of the caspase family, is considered an initiator caspase that triggers apoptosis in response to some cellular stresses. Previous studies suggest that an intracellular multi-protein complex PIDDosome, induced by genotoxic stress, serves as a platform for caspase-2 activation. Due to caspase-2's inability to process effector caspases, however, the mechanism underlying caspase-2-mediated cell death upon PIDDosome activation remains unclear. Here, we conducted an unbiased genome-wide genetic screen and identified that the Bcl2 family protein BID is required for PIDDosome-induced, caspase-2-mediated apoptosis. PIDDosome-activated caspase-2 directly and functionally processes BID to signal the mitochondrial pathway for apoptosis induction. In addition, a designed chemical screen identified a compound, HUHS015, which specifically activates caspase-2-mediated apoptosis. HUHS015-stimulated apoptosis also requires BID but is independent of the PIDDosome. Through extensive structure-activity relationship efforts, we identified a derivative with a potency of ~60 nmol/L in activating caspase-2-mediated apoptosis. The HUHS015-series of compounds act as efficient agonists that directly target the interdomain linker in caspase-2, representing a new mode of initiator caspase activation. Human and mouse caspase-2 differ in two crucial residues in the linker, rendering a selectivity of the agonists for human caspase-2. The caspase-2 agonists are valuable tools to explore the physiological roles of caspase-2-mediated cell death and a base for developing small-molecule drugs for relevant diseases.
Caspase 2/genetics* ; Humans ; BH3 Interacting Domain Death Agonist Protein/metabolism* ; Apoptosis/drug effects* ; Death Domain Receptor Signaling Adaptor Proteins/metabolism* ; Animals ; Mice ; Cysteine Endopeptidases