mTORC2 Facilitates Liver Regeneration Through Sphingolipid-Induced PPAR-α-Fatty Acid Oxidation

BACKGROUND & AIMS

During liver regeneration after partial hepatectomy, the function and metabolic pathways governing transient lipid droplet accumulation in hepatocytes remain obscure. Mammalian target of rapamycin 2 (mTORC2) facilitates de novo synthesis of hepatic lipids. Under normal conditions and in tumorigenesis, decreased levels of triglyceride (TG) and fatty acids (FAs) are observed in the mTORC2-deficient liver. However, during liver regeneration, their levels increase in the absence of mTORC2.

METHODS

Rictor liver-specific knockout and control mice underwent partial hepatectomy, followed by measurement of TG and FA contents during liver regeneration. FA metabolism was evaluated by analyzing the expression of FA metabolism-related genes and proteins. Intraperitoneal injection of the peroxisome proliferator-activated receptor α (PPAR-α) agonist, p53 inhibitor, and protein kinase B (AKT) activator was performed to verify the regulatory pathways involved. Lipid mass spectrometry was performed to identify the potential PPAR-α activators.

RESULTS

The expression of FA metabolism-related genes and proteins suggested that FAs are mainly transported into hepatocytes during liver regeneration. The PPAR-α pathway is down-regulated significantly in the mTORC2-deficient liver, resulting in the accumulation of TGs. The PPAR-α agonist WY-14643 rescued deficient liver regeneration and survival in mTORC2-deficient mice. Furthermore, lipidomic analysis suggested that mTORC2 deficiency substantially reduced glucosylceramide (GluCer) content. GluCer activated PPAR-α. GluCer treatment in vivo restored the regenerative ability and survival rates in the mTORC2-deficient group.

CONCLUSIONS

Our data suggest that FAs are mainly transported into hepatocytes during liver regeneration, and their metabolism is facilitated by mTORC2 through the GluCer-PPAR-α pathway, thereby establishing a novel role for mTORC2 in lipid metabolism.

[Epidemiological characteristics of COVID-19 monitoring cases in Yinzhou district based on health big data platform]

Objective: To understand the epidemiological characteristics of COVID-19 monitoring cases in Yinzhou district based on health big data platform to provide evidence for the construction of COVID-19 monitoring system. Methods: Data on Yinzhou COVID-19 daily surveillance were collected. Information on patients' population classification, epidemiological history, COVID-19 nucleic acid detection rate, positive detection rate and confirmed cases monitoring detection rate were analyzed. Results: Among the 1 595 COVID-19 monitoring cases, 79.94% were community population and 20.06% were key population. The verification rate of monitoring cases was 100.00%. The total percentage of epidemiological history related to Wuhan city or Hubei province was 6.27% in total, and was 2.12% in community population and 22.81% in key population (P<0.001). The total COVID-19 nucleic acid detection rate was 18.24% (291/1 595), and 53.00% in those with epidemiological history and 15.92% in those without (P<0.001).The total positive detection rate was 1.72% (5/291) and the confirmed cases monitoring detection rate was 0.31% (5/1 595). The time interval from the first visit to the first nucleic acid detection of the confirmed monitoring cases and other confirmed cases was statistically insignificant (P>0.05). Conclusions: The monitoring system of COVID-19 based on the health big data platform was working well but the confirmed cases monitoring detection rate need to be improved.

p16 gene expression in pancreatic cancer tissue and its importance in diagnosis

The aim of this study was to assess the importance of p16 gene expressions in pancreatic cancer tissue for early diagnosis and treatment. Two groups were included in the study: an experimental group of 35 pancreatic cancer tissue specimens and a control group of 35 pancreatic cancer adjacent tissues collected during surgery. The expression of p16 gene in the two groups was observed using the immunohistochemical streptavidin peroxidase conjugated (S-P) method. The results were statistically interpreted using SPSS22.0 software. The positive expression rate of p16 in the experimental group was lower than that of the control group (p less than 0.05). Comparing the intensity of p16 gene expression, differentiation degree, clinical stage and metastases of nearby lymph nodes the differences had statistical significance (p less than 0.05). The intensity of p16 gene expression in high and medium differentiated pancreatic cancer group was higher than that of the low differentiated group. p16 gene expression in stages III and IV groups was lower than that in stages I and II groups. Differentiation degree, clinical stage, metastases of nearby lymph nodes and distant metastasss were negatively related with p16 gene expression (p less than 0.05). There was no correlation between age or gender and p16 gene expression. The decreased expression of p16 gene in pancreatic cancer tissue was negatively correlated with differentiation degree and clinical stage. Our results indicated that p16 can be used as a cue signal for diagnosing advanced pancreatic cancer.

An Isoquinolin-1(2H)-Imine Derivative Induces Cell Death via Generation of Reactive Oxygen Species and Activation of JNK in Human A549 Cancer Cells

Compound 11-benzoyl-10-chloro-7,9-difluoro-6-imino-2,3,4,6-tetrahydro-1H-pyrimido[1,2-b]isoquinoline-8-carbonitrile (HC6h) is a novel polyhalo 1,3-diazaheterocycle fused isoquinolin-1(2H)-imines derivative, which displays good anticancer activity and low toxicity in vivo. However, the underlying anticancer mechanisms have not previously been identified. The proliferation of A549 was assessed by MTT assay. The reactive oxygen species (ROS) level was assessed in A549 with a H₂ DCFDA probe. Mitochondrial membrane potential was measured using the JC-1 staining. Apoptosis were measured by annexin-V/PI assay and autophagy by acridine orange staining and GFP-LC3 fluorescence assay. The expression of autophagic and apoptotic proteins was determined by Western blot. The compound HC6h increased accumulation of vesicles, acridine orange-stained cells and LC3-II in A549 cells. Inhibition of compound HC6h-induced autophagy by bafilomycin A1 increased apoptosis. Compound HC6h enhanced activation of caspase-3, caspase-9 and PARP cleavage in A549 cells. Compound HC6h leads to the rapid generation of intracellular ROS. Moreover, compound HC6h induced phosphorylation of JNK and was conferred by the increased ROS levels. Furthermore, down-regulation of JNK attenuated autophagic and apoptotic effect in response to HC6h. The induction of ROS upon HC6h treatment leads to the activation of JNK that mediates autophagy and apoptosis in human A549 cancer cells. J. Cell. Biochem. 118: 4394-4403, 2017. © 2017 Wiley Periodicals, Inc.

Specific serology for emerging human coronaviruses by protein microarray

We present a serological assay for the specific detection of IgM and IgG antibodies against the emerging human coronavirus hCoV-EMC and the SARS-CoV based on protein microarray technology. The assay uses the S1 receptor-binding subunit of the spike protein of hCoV-EMC and SARS-CoV as antigens. The assay has been validated extensively using putative cross-reacting sera of patient cohorts exposed to the four common hCoVs and sera from convalescent patients infected with hCoV-EMC or SARS-CoV.

A candidate precursor to serous carcinoma that originates in the distal fallopian tube

The tubal fimbria is a common site of origin for early (tubal intraepithelial carcinoma or TIC) serous carcinomas in women with familial BRCA1 or 2 mutations (BRCA+). Somatic p53 tumour suppressor gene mutations in these tumours suggest a pathogenesis involving DNA damage, p53 mutation, and progressive loss of cell cycle control. We recently identified foci of strong p53 immunostaining-termed 'p53 signatures'-in benign tubal mucosa from BRCA+ women. To examine the relationship between p53 signatures and TIC, we compared location (fimbria vs ampulla), cell type (ciliated vs secretory), evidence of DNA damage, and p53 mutation status between the two entities. p53 signatures were equally common in non-neoplastic tubes from BRCA+ women and controls, but more frequently present (53%) and multifocal (67%) in fallopian tubes also containing TIC. Like prior studies of TIC, p53 signatures predominated in the fimbriae (80-100%) and targeted secretory cells (HMFG2 + /p73-), with evidence of DNA damage by co-localization of gamma-H2AX. Laser-capture microdissected and polymerase chain reaction-amplified DNA revealed reproducible p53 mutations in eight of 14 fully-analysed p53 signatures and all of the 12 TICs; TICs and their associated ovarian carcinomas shared identical mutations. In one case, a contiguous p53 signature and TIC shared the same mutation. Morphological intermediates between the two, with p53 mutations and moderate proliferative activity, were also seen. This is the first report of an early and distinct alteration in non-neoplastic upper genital tract mucosa that fulfils many requirements for a precursor to pelvic serous cancer. The p53 signature and its malignant counterpart (TIC) underline the significance of the fimbria, both as a candidate site for serous carcinogenesis and as a target for future research on the early detection and prevention of this disease.

The Catalytic and GAF Domains of the Rod cGMP Phosphodiesterase (PDE6) Heterodimer Are Regulated by Distinct Regions of Its Inhibitory γ Subunit

The central effector of visual transduction in retinal rod photoreceptors, cGMP phosphodiesterase (PDE6), is a catalytic heterodimer (alphabeta) to which low molecular weight inhibitory gamma subunits bind to form the nonactivated PDE holoenzyme (alphabetagamma(2)). Although it is known that gamma binds tightly to alphabeta, the binding affinity for each gamma subunit to alphabeta, the domains on gamma that interact with alphabeta, and the allosteric interactions between gamma and the regulatory and catalytic regions on alphabeta are not well understood. We show here that the gamma subunit binds to two distinct sites on the catalytic alphabeta dimer (K(D)(1) < 1 pm, K(D)(2) = 3 pm) when the regulatory GAF domains of bovine rod PDE6 are occupied by cGMP. Binding heterogeneity of gamma to alphabeta is absent when cAMP occupies the noncatalytic sites. Two major domains on gamma can interact independently with alphabeta with the N-terminal half of gamma binding with 50-fold greater affinity than its C-terminal, inhibitory region. The N-terminal half of gamma is responsible for the positive cooperativity between gamma and cGMP binding sites on alphabeta but has no effect on catalytic activity. Using synthetic peptides, we identified regions of the amino acid sequence of gamma that bind to alphabeta, restore high affinity cGMP binding to low affinity noncatalytic sites, and retard cGMP exchange with both noncatalytic sites. Subunit heterogeneity, multiple sites of gamma interaction with alphabeta, and positive cooperativity of gamma with the GAF domains are all likely to contribute to precisely controlling the activation and inactivation kinetics of PDE6 during visual transduction in rod photoreceptors.

cGMP binding to noncatalytic sites on mammalian rod photoreceptor phosphodiesterase is regulated by binding of its gamma and delta subunits

The binding of cGMP to the noncatalytic sites on two isoforms of the phosphodiesterase (PDE) from mammalian rod outer segments has been characterized to evaluate their role in regulating PDE during phototransduction. Nonactivated, membrane-associated PDE (PDE-M, alpha beta gamma2) has one exchangeable site for cGMP binding; endogenous cGMP remains nonexchangeable at the second site. Non-activated, soluble PDE (PDE-S, alpha beta gamma2 delta) can release and bind cGMP at both noncatalytic sites; the delta subunit is likely responsible for this difference in cGMP exchange rates. Removal of the delta and/or gamma subunits yields a catalytic alphabeta dimer with identical catalytic and binding properties for both PDE-M and PDE-S as follows: high affinity cGMP binding is abolished at one site (KD >1 microM); cGMP binding affinity at the second site (KD approximately 60 nM) is reduced 3-4-fold compared with the nonactivated enzyme; the kinetics of cGMP exchange to activated PDE-M and PDE-S are accelerated to similar extents. The properties of nonactivated PDE can be restored upon addition of gamma subunit. Occupancy of the noncatalytic sites by cGMP may modulate the interaction of the gamma subunit with the alphabeta dimer and thereby regulate cytoplasmic cGMP concentration and the lifetime of activated PDE during visual transduction in photoreceptor cells.

Growth regulation of ovarian cancer cell line HO-8910 by transforming growth factor beta 1 in vitro

OBJECTIVE

To further understand the role of growth regulation of human ovarian cancer cells by transforming growth factor (TGF) beta 1.

METHODS

The cell proliferation, cAMP synthesis, gene expression, and induction of programmed cell death (PCD) in human epithelial ovarian cancer cell line HO-8910 cells exposed to TGF beta 1 in vitro were studied.

RESULTS

TGF beta 1 inhibited cell growth and DNA synthesis, and induced G0/G1 arrest in cell cycle. It could also trigger PCD in cells. This induction of PCD may occur within G0/G1 phase. Meanwhile, the assay also showed that TGF beta 1 could inhibit the mRNA expression of c-myc, EGFR and TGF beta 1 genes in cells.

CONCLUSIONS

TGF beta 1 can not only act as an autocrine to inhibit cell proliferation, but also trigger PCD in HO-8910 cells. These functions may be fulfilled through some specific signal transduction pathways.

[A study on the anti-metastatic effects of CD3Ak cells in nude mice]

OBJECTIVE

To investigate whether cancer draining lymph node lymphocytes activated by CD3 McAB in vitro have anti-tumor effects in vivo.

METHODS

Nude mice with highly metastatic human ovarian cancer were treated with CD3 McAB activated killer cells (CD3AK) from human ovarian cancer draining lymph node lymphocytes. 31 experimental nude mice were divided into 4 groups; the cisplatin group (7 mice), the CD3AK cells group (7 mice), the combined treatment group (7 mice), and control group (10 mice). Treatment began on the 10th day after tumor transplantation for a total of 80 days.

RESULTS

The transplanted tumors disappeared in 1 mouse of CD3AK group, significant difference in the anti-metastatic effect was found between the CD3AK group (2/7 mice with metastasis) and the control group (8/10 mice with metastasis). Significant difference in average tumor volume was found between the CD3AK group (0.5788 +/- 0.2549) and the control group (1.5685 +/- 0.283). The tumor growth inhibition rate reached 63.1% in the CD3AK group. Significant difference in the serum level of progesterone was found between the CD3AK group (3.3843 +/- 0.5314) and the control group (6.3480 +/- 0.7615). Significant difference in the histiocyte increase in the lymph node sinuses was found between the CD3AK group (59/69) and the control group (55/94).

CONCLUSION

These results suggest that CD3AK cells appear to be effective in tumor growth inhibition, anti-metastasis and enhancing host immunologic function.

[Induction of apoptosis in human ovarian cancer cell line HO-8910 by transforming growth factor beta 1]

OBJECTIVE

To investigate the mechanism of inhibitory effects of Transforming Growth Factor beta 1 (TGF-beta 1) on human ovarian cancer cell in vitro.

METHODS

The possibility of induction of apoptosis in human ovarian cancer cell line HO-8910 cells after treatment with TGF-beta 1 was studied by using methods of DNA electrophoresis, P1-staining, TdT-mediated dUTP-x nick end labeling and flow cytometer assay (FCM); and the kinetic change of expression of c-myc was also studied by relative quantified RT-PCR.

RESULTS

DNA-strand nicks were present in cells after treatment with TGF-beta 1 at the final concentration of 20 ng/ml for 36 hours. The percent of labeled cells reached 75.55% on the time of 48 hours, PI staining-FCM assay also showed subdiploid peak of apoptotic cells at the same time. The typical apoptotic DNA ladder was present in genomic DNA preparation after treatment with TGF-beta 1 for 60 hours, meanwhile, the expression of c-myc in cells started to decrease beginning at treatment for 9 hours.

CONCLUSIONS

TGF-beta 1 can induce apoptosis in HO-8910; such an inductive effect may occur mainly in G0/G1 phase. The effects of TGF-beta 1 on the inhibited expression of c-myc and on the enhancement of cAMP concentration may also play important roles in the process of apoptotic induction.

3-Ketoglycoside-mediated metabolism of sucrose in E. coli as conferred by genes from Agrobacterium tumefaciens

Escherichia coli strains that did not have the ability to use sucrose as a sole carbon source gained this ability after receiving a cloned fragment of DNA from Agrobacterium tumefaciens. No invertase was detected in the sucrose-metabolizing E. coli, but evidence for the activity of certain enzymes, known to be produced by biotype 1 strains of Agrobacterium, were found. Evidence was found for the presence of D-glucoside 3-dehydrogenase (G3DH) and alpha-3-ketoglucosidase. The activity of enzyme extracts on 3-ketosucrose also indicated that 3-ketoglucose reductase, or some enzyme that acts on 3-ketoglucose, was present in the Suc+ E. coli as well. The fragment was found to complement a G3DH mutant of A. tumefaciens and was also found to confer chemotaxis towards sucrose in E. coli.

[Establishment and characterization of a model of highly metastatic human ovarian cancer transplanted subcutaneously into nude mice]

A model of highly metastatic human ovarian cancer transplanted subcutaneously into nude mice was established (NMSO). Although the NMSO transplanted tumors were passaged 23 times, they retained their highly metastatic behavior. A total of 57 adult Balc/c nude mice (8-14 weeks old) were inoculated (SC) with tumor, the transplantations were 100% successful and the average survival period was 159.9 days. 47 mice were dissected and 42 mice were found to have metastatic tumors. The earliest appearance of metastasis was 56 dys. 18 male nude mice all had metastasis. Histology and ultrastructure showed that the metastatic tumors retained their malignant features and secreting function of the original poorly differentiated human ovarian serous papillary cystadenocarcinoma. FCM analysis gave a 1.4 DNA index and the chromosome mode number was 54 (hyper-diploid), exhibiting the features of human carcinoma. The detection of correlative label material showed that most cancer cells were ER and PR positive. The use of NMSO model may lead to better understanding of the mechanism of metastasis and help search for anti-metastatic agents.