Guidance for life, cell death, and colorectal neoplasia by netrin dependence receptors

Netrin-1 in Post-stroke Neuroprotection: Beyond Axon Guidance Cue

BACKGROUND

Stroke, especially ischemic stroke, is a leading disease associated with death and long-term disability with limited therapeutic options. Neuronal death caused by vascular impairment, programmed cell death and neuroinflammation has been proven to be associated with increased stroke severity and poor stroke recovery. In light of this, a development of neuroprotective drugs targeting injured neurons is urgently needed for stroke treatment. Netrin-1, known as a bifunctional molecule, was originally described to mediate the repulsion or attraction of axonal growth by interacting with its different receptors. Importantly, accumulating evidence has shown that netrin-1 can manifest its beneficial functions to brain tissue repair and neural regeneration in different neurological disease models.

OBJECTIVE

In this review, we focus on the implications of netrin-1 and its possibly involved pathways on neuroprotection after ischemic stroke, through which a better understanding of the underlying mechanisms of netrin-1 may pave the way to novel treatments.

METHODS

Peer-reviewed literature was recruited by searching databases of PubMed, Scopus, Embase, and Web of Science till the year 2021.

CONCLUSION

There has been certain evidence to support the neuroprotective function of netrin-1 by regulating angiogenesis, autophagy, apoptosis and neuroinflammation after stroke. Netrin-1 may be a promising drug candidate in reducing stroke severity and improving outcomes.

Expression of PI3-K, PKB and GSK-3 β in the skeletal muscle tissue of gestational diabetes mellitus

OBJECTIVE

To analyze the expression of phosphatidylinositol 3 kinase (PI3-K), protein kinase B (PKB) and glycogen synthase kinase 3 beta (GSK-3 β) in skeletal muscle tissue of gestational diabetes mellitus (GDM).

METHODS

A total of 90 cases of pregnant women were divided into observation group and control group according to the occurrence of GDM with 45 cases in either, and the expression of PI3-K, PKB, GSK-3 β mRNA expression in skeletal muscle tissue was compared between two groups.

RESULTS

The total PI3-K p85 protein was significantly higher in the observation group compared with the control group, the activity of PI3-K was lower than that of the latter; The total PKB, GSK-3 β protein in skeletal tissue had no significant difference between two groups, while the serine phosphorylation levels of PKB and GSK-3β were significantly lower in observation group compared with the control group.

CONCLUSIONS

The downregulation of PI3-K, PKB and GSK-3βin skeletal tissue of GDM caused by phosphorylation dysfunction of signaling molecules is the reason for insulin resistance and transporter function decline which lead to GDM.

Gene expression changes consistent with neuroAIDS and impaired working memory in HIV-1 transgenic rats

BACKGROUND

A thorough investigation of the neurobiology of HIV-induced neuronal dysfunction and its evolving phenotype in the setting of viral suppression has been limited by the lack of validated small animal models to probe the effects of concomitant low level expression of multiple HIV-1 products in disease-relevant cells in the CNS.

RESULTS

We report the results of gene expression profiling of the hippocampus of HIV-1 Tg rats, a rodent model of HIV infection in which multiple HIV-1 proteins are expressed under the control of the viral LTR promoter in disease-relevant cells including microglia and astrocytes. The Gene Set Enrichment Analysis (GSEA) algorithm was used for pathway analysis. Gene expression changes observed are consistent with astrogliosis and microgliosis and include evidence of inflammation and cell proliferation. Among the genes with increased expression in HIV-1 Tg rats was the interferon stimulated gene 15 (ISG-15), which was previously shown to be increased in the cerebrospinal fluid (CSF) of HIV patients and to correlate with neuropsychological impairment and neuropathology, and prostaglandin D2 (PGD2) synthase (Ptgds), which has been associated with immune activation and the induction of astrogliosis and microgliosis. GSEA-based pathway analysis highlighted a broad dysregulation of genes involved in neuronal trophism and neurodegenerative disorders. Among the latter are genesets associated with Huntington's disease, Parkinson's disease, mitochondrial, peroxisome function, and synaptic trophism and plasticity, such as IGF, ErbB and netrin signaling and the PI3K signal transduction pathway, a mediator of neural plasticity and of a vast array of trophic signals. Additionally, gene expression analyses also show altered lipid metabolism and peroxisomes dysfunction. Supporting the functional significance of these gene expression alterations, HIV-1 Tg rats showed working memory impairments in spontaneous alternation behavior in the T-Maze, a paradigm sensitive to prefrontal cortex and hippocampal function.

CONCLUSIONS

Altogether, differentially regulated genes and pathway analysis identify specific pathways that can be targeted therapeutically to increase trophic support, e.g. IGF, ErbB and netrin signaling, and reduce neuroinflammation, e.g. PGD2 synthesis, which may be beneficial in the treatment of chronic forms of HIV-associated neurocognitive disorders in the setting of viral suppression.

TAGLN suppresses proliferation and invasion, and induces apoptosis of colorectal carcinoma cells

In order to find the correlation between transgelin gene (TAGLN) and colorectal carcinoma occurrence, we investigated the expression of TAGLN in colorectal carcinoma tissue samples and colorectal carcinoma LoVo cells. Meanwhile, the effects of TAGLN on the characteristics of LoVo cells were also examined. The expressions of TAGLN in colorectal carcinoma tissues, adjacent normal tissues, and LoVo cells were detected by the Western blot method. The recombinant plasmid pcDNA3.1-TAGLN was established and transfected into LoVo cells with the help of Lipofectamine™ 2000. At the same time, the TAGLN siRNA was transfected into LoVo cells in another group. Forty-eight hours later, the expressions of TAGLN in all groups were assayed by Western blot, and the cell viability was analyzed by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. The cell cycle and cell apoptosis were examined by flow cytometry, and the cell invasive ability was analyzed by Transwell invasion experiment. The effect of TALGN on the expression of matrix metalloproteinase 9 (MMP9) was detected by Western blot. Western blot analysis showed that the expressions of TALGN in colorectal carcinoma tissues and LoVo cells were significantly decreased compared with colorectal carcinoma adjacent normal tissues (p < 0.01). In the overexpression or RNAi experiments, the plasmid pcDNA3.1-TAGLN significantly enhanced TALGN expression (p < 0.01), and TAGLN siRNA significantly decreased TAGLN expression (p < 0.01) in LoVo cells 48 h after transfection. In addition, MTT assay indicated that the cell viability of LoVo cells in the pcDNA3.1-TAGLN transfection group was significantly lower than that in the untransfected control group (p < 0.05). Furthermore, the overexpression of TAGLN significantly lowered the cell proliferation index (p < 0.05) and improved cell apoptosis (p < 0.01) in LoVo cells. In Transwell invasive experiments, the cell number, which had migrated through the chamber membrane, significantly decreased in the pcDNA3.1-TAGLN transfection group (p < 0.05) and significantly increased in the TAGLN knockdown group (p < 0.05) compared to the untransfected control group. At the same time, the expression of MMP9 was notably inhibited in the pcDNA3.1-TAGLN transfection group (p < 0.01). The expressions of TAGLN were inhibited in colorectal carcinoma tissues and colorectal carcinoma LoVo cells. The study also demonstrated that TAGLN could attenuate the proliferation and invasive ability of LoVo cells and enhance LoVo cell apoptosis. Furthermore, the expression of MMP9 was also inhibited by TAGLN. All these results could bring us a new perspective for biological therapy in colorectal carcinoma.