Humans ; Osteosarcoma ; metabolism ; Signal Transduction ; physiology ; TOR Serine-Threonine Kinases ; metabolism

Necroptosis is one of the regulated cell death, which involves receptor interacting protein kinase (RIPK) 1/RIPK3/mixed lineage kinase domain like protein (MLKL) signaling pathway. Among them, MLKL is the final execution of necroptosis. The formation of RIPK1/RIPK3/MLKL necrosome induces the phosphorylated MLKL, and the activated MLKL penetrates into the membrane bilayer to form membrane pores, which damages the integrity of the membrane and leads to cell death. In addition to participating in necroptosis, MLKL is also closely related to other cell death, such as NETosis, pyroptosis, and autophagy. Therefore, MLKL is involved in the pathological processes of various diseases related to abnormal cell death pathways (such as cardiovascular diseases, neurodegenerative diseases and cancer), and may be a therapeutic target of multiple diseases. Understanding the role of MLKL in different cell death can lay a foundation for seeking various MLKL-related disease targets, and also guide the development and application of MLKL inhibitors.
Protein Kinases/metabolism* ; Necroptosis/physiology* ; Receptor-Interacting Protein Serine-Threonine Kinases ; Signal Transduction ; Pyroptosis ; Apoptosis

BubR1 gene is a homologue of the mitotic checkpoint gene Mad3 in budding yeast which is highly conserved in mammalian. BubR1 protein is a key component mediating spindle assembly checkpoint activation. BubR1 safeguards accurate chromosome segregation during cell division by monitoring kinetochore-microtubule attachments and kinetochore tension. There is a dose-dependent effect between the level of BubR1 expression and the function of spindle assembly checkpoint. BubR1-deficient would lead to mitotic progression with compromised spindle assembly checkpoint because cells become progressively aneuploid. Recently, it has been reported that BubR1 also plays important roles in meiotic, DNA damage response, cancer, infertility, and early aging. This review briefly summarizes the current progresses in studies of BubR1 function.
Cell Cycle Proteins ; genetics ; metabolism ; physiology ; Chromosome Segregation ; genetics ; physiology ; Kinetochores ; metabolism ; physiology ; Mitosis ; genetics ; physiology ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; physiology ; Saccharomycetales ; genetics ; physiology ; Spindle Apparatus ; genetics ; metabolism ; physiology

While several organs in mammals retain partial regenerative capability following tissue damage, the underlying mechanisms remain unclear. Recently, the Hippo signaling pathway, better known for its function in organ size control, has been shown to play a pivotal role in regulating tissue homeostasis and regeneration. Upon tissue injury, the activity of YAP, the major effector of the Hippo pathway, is transiently induced, which in turn promotes expansion of tissue-resident progenitors and facilitates tissue regeneration. In this review, with a general focus on the Hippo pathway, we will discuss its major components, functions in stem cell biology, involvement in tissue regeneration in different organs, and potential strategies for developing Hippo pathway-targeted regenerative medicines.
Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Homeostasis ; physiology ; Humans ; Phosphoproteins ; metabolism ; Protein-Serine-Threonine Kinases ; metabolism ; Regeneration ; physiology ; Signal Transduction ; physiology

Animals ; Eukaryotic Initiation Factors ; genetics ; metabolism ; Humans ; Phosphorylation ; physiology ; Proteomics ; Ribosomal Proteins ; genetics ; metabolism ; TOR Serine-Threonine Kinases ; genetics ; metabolism

Corynebacterium glutamicum SYPS-062 was an L-serine producing strain stored at our lab and could produce L-serine directly from sugar. We studied the effects of cofactors in one carbon unit metabolism-folate and VB12 on the cell growth, sucrose consumption and L-serine production by SYPS-062. In the same time, the metabolic flux distribution was determined in different conditions. The supplementation of folate or VB12 enhanced the cell growth, energy synthesis, and finally increased the flux of pentose phosphate pathway (HMP), whereas the carbon flux to L-serine was decreased. The addition of VB12 not only increased the ratio of L-serine synthesis pathway on G3P joint, but also caused the insufficiency of tricarboxylic acid cycle (TCA) flux, which needed more anaplerotic reaction flux to replenish TCA cycle, that was an important limiting factor for the further increasing of the L-serine productivity.
Citric Acid Cycle ; physiology ; Corynebacterium glutamicum ; metabolism ; Fermentation ; Folic Acid ; pharmacology ; Serine ; biosynthesis ; Vitamin B 12 ; pharmacology

OBJECTIVETo observe the expression of serine protease HtrA1 in human periodontal ligament tissue and to explore the effect of HtrA1 on the proliferation of human periodontal ligament cells (hPDLC).

METHODSSix human premolars and three human third molars(patient's ages ranging from 12 to 25, with intact root, without caries and/or periodontitis) were obtained in the Department of Maxillofacial Surgery of Wuhan University Hospital of Stomatology. Reverse transcription-PCR(RT-PCR) and immunohistochemistry analysis were applied to investigate the expression of HtrA1. Primary hPDLC were obtained by tissue-culture method in vitro. The proliferation of hPDLC was determined by methyl thiazolytetrazolium(MTT). Lentivirus-mediated over-expression and reduction of HtrA1 level was performed. An empty vector was used as negative control. On days 1, 3, 5, 7 and 9, the growth of hPDLC was characterized using cell counting kit-8(CCK-8) assay.

RESULTSRT-PCR data indicated that HtrA1 mRNA was expressed in human periodontal ligament tissue. Immunohistochemistry analysis showed HtrA1 was expressed in human periodontal ligament, mainly in the cytoplasm of hPDLC and the extracellular matrix. The MTT result suggested that the growth curve was consistent with the growth characteristics of hPDLC. The stable over-expression and knockdown cell lines was successfully established by lentivirus with more than 90% transfection efficiency. CCK-8 assay showed that HtrA1 over-expression inhibited the proliferation of hPDLC(0.897±0.060, 0.890±0.083, 1.631±0.038, 1.111±0.041, 1.110±0.189), while cell proliferation increased after down-regulation of HtrA1(0.329±0.021, 0.529±0.044, 0.973±0.056, 1.626±0.102, 2.344±0.198)(P<0.05).

CONCLUSIONSHtrA1 is expressed in human periodontal ligament tissue at both mRNA and protein levels, and may play an important role in regulating the proliferation of hPDLC.

Adolescent ; Adult ; Cell Count ; Cell Proliferation ; Cells, Cultured ; Child ; Down-Regulation ; Genetic Vectors ; High-Temperature Requirement A Serine Peptidase 1 ; Humans ; Lentivirus ; physiology ; Periodontal Ligament ; cytology ; metabolism ; RNA, Messenger ; metabolism ; Serine Endopeptidases ; genetics ; metabolism ; Transfection ; Young Adult

Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
Astrocytes/metabolism ; Cell Death ; Epilepsy/diet therapy/drug therapy/*metabolism/virology ; Humans ; Ketogenic Diet ; Protein Binding/physiology ; Protein Kinase Inhibitors/therapeutic use ; Receptors, Cannabinoid/metabolism ; Signal Transduction/*physiology ; Synapses/metabolism ; TOR Serine-Threonine Kinases/antagonists & inhibitors/*metabolism ; Temporal Lobe/metabolism

BackgroundRecent studies have indicated that autophagy is involved in sepsis-induced myocardial dysfunction. This study aimed to investigate the change of autophagy in cecal ligation and puncture (CLP)-induced myocardium dysfunction and its relationship with mammalian target of rapamycin (mTOR) pathway.

MethodsTotally, 12 rats were randomly divided into CLP group or sham-operated (SHAM) group. Cardiac tissues were harvested 18 h after CLP or sham operation. Pathology was detected by hematoxylin and eosin staining, cardiac functions by echocardiography, distribution of microtubule-associated protein light chain 3 type II (LC3II) by immunohistochemical staining, and autophagic vacuoles by transmission electron microscopy. Moreover, phosphorylation of mTOR (p-mTOR), phosphorylation of S6 kinase-1 (PS6K1), and LC3II and p62 expression were measured by western blotting. Pearson's correlation coefficient was used to analyze the correlation of two parameters.

ResultsThe results by pathology and echocardiography revealed that there was obvious myocardial injury in CLP rats (left ventricle ejection fraction: SHAM 0.76 ± 0.06 vs. CLP 0.59 ± 0.11, P < 0.01; fractional shortening: SHAM 0.51 ± 0.09 vs. CLP 0.37 ± 0.06, P < 0.05). We also found that the autophagy process was elevated by CLP, the ratio of LC3II/LC3I was increased (P < 0.05) while the expression of p62 was decreased (P < 0.05) in the CLP rats, and there were also more autophagosomes and autolysosomes in the CLP rats. Furthermore, the mTOR pathway in CLP myocardium was inhibited when compared with the sham-operated rats; p-mTOR (P < 0.01) and PS6K1 (P < 0.05) were both significantly suppressed following CLP challenge. Interestingly, we found that the mTOR pathway was closely correlated with the autophagy processes. In our study, while p-mTOR in the myocardium was significantly correlated with p62 (r = 0.66, P = 0.02), PS6K1 was significantly positively correlated with p62 (r = 0.70, P = 0.01) and negatively correlated with LC3II (r = -0.71, P = 0.01).

ConclusionsThe autophagy process in the myocardium was accelerated in CLP rats, which was closely correlated with the inhibition of the mTOR pathway.

Animals ; Autophagy ; physiology ; Cecum ; injuries ; Echocardiography ; Immunohistochemistry ; Ligation ; Male ; Microscopy, Electron, Transmission ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Sepsis ; metabolism ; TOR Serine-Threonine Kinases ; metabolism

The recent development of a prosaposin -/- mouse model has allowed the investigation of the role of prosaposin in the development of the male reproductive organs. A morphometric analysis of the male reproductive system of 37 days old mice revealed that prosaposin ablation produced a 30 % reduction in size and weight of the testes, 37 % of the epididymis, 75 % of the seminal vesicles and 60 % of the prostate glands. Light microscopy (LM) showed that smaller testis size from homozygous mutant mice was associated with reduced spermiogenesis. Both, dorsal and ventral lobules of the prostate glands were underdeveloped in the homozygous mutant. LM analysis also showed that prostatic alveoli were considerably smaller and lined by shorter epithelial cells in the homozygous mutant. Smaller tubular diameter and shorter undifferentiated epithelial cells were also observed in seminal vesicles and epididymis. In the efferent ducts of the homozygous mutant mice, the epithelium was composed exclusively of ciliated cells in contrast to the heterozygotes, which showed the presence of nonciliated cells. Radioimmunoassays demonstrated that testosterone levels were normal or higher in mice with the inactivated prosaposin gene. Immunostaining of prostate sections with an anti-androgen receptor antibody showed that the epithelial cells lining the alveoli express androgen receptor in both the heterozygous and homozygous tissue. Similarly, sections immunostained with antibodies to the phosphorylated MAPKs and Akts strongly reacted with tall prostatic secretory cells in prostate from heterozygous mouse. On the other hand, the epithelial cells in the homozygous prostate remained unstained or weakly stained. These findings demonstrate that inactivation of the prosaposin gene affected the development of the prostate gland and some components of the MAPK pathway.
Animals ; Glycoproteins ; metabolism ; Humans ; MAP Kinase Signaling System ; physiology ; Male ; Prostate ; growth & development ; metabolism ; Protein-Serine-Threonine Kinases ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-akt ; Saposins