Sphingolipids have been implicated in the etiology of chronic metabolic diseases. Here, we investigated whether sphingolipid biosynthesis is associated with the development of adipose tissues and metabolic diseases. SPTLC2, a subunit of serine palmitoyltransferase, was transcriptionally upregulated in the adipose tissues of obese mice and in differentiating adipocytes. Adipocyte-specific SPTLC2-deficient (aSPTLC2 KO) mice had markedly reduced adipose tissue mass. Fatty acids that were destined for the adipose tissue were instead shunted to liver and caused hepatosteatosis. This impaired fat distribution caused systemic insulin resistance and hyperglycemia, indicating severe lipodystrophy. Mechanistically, sphingosine 1-phosphate (S1P) was reduced in the adipose tissues of aSPTLC2 KO mice, and this inhibited adipocyte proliferation and differentiation via the downregulation of S1P receptor 1 and decreased activity of the peroxisome proliferator-activator receptor γ. In addition, downregulation of SREBP (sterol regulatory element-binding protein)-1c prevented adipogenesis of aSPTLC2 KO adipocytes. Collectively, our observations suggest that the tight regulation of de novo sphingolipid biosynthesis and S1P signaling plays an important role in adipogenesis and hepatosteatosis.

No abstract

No abstract

The human gastrointestinal tract harbors a magnitude of bacteria, which are collectively known as the gut microbiome. Research has demonstrated that the gut microbiome significantly impacts the health of its host and alters the host’s risk for various chronic diseases. Many factors, such as diet, could potentially be manipulated to alter the host gut microbiome and induce subsequent preventative and/or therapeutic effects. It has been established that diet partakes in the regulation and maintenance of the gut microbiome; however, specific crosstalk between the microbiome, gut, and host has not been clearly elucidated in relation to diet. In this review of the scientific literature, we outline current knowledge of the differential effects of major plant-derived dietary constituents (fiber, phytochemicals, vitamins, and minerals) on the diversity and composition of the gut microbiome.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is associated with systemic inflammation and results in the destruction of joints and cartilage. The pathogenesis of RA involves a complex inflammatory process resulting from the action of various proinflammatory cytokines and, therefore, many novel therapeutic agents to block cytokines or cytokine-mediated signaling have been developed. Here, we tested the preventive effects of a small peptide, AESIS-1, in a mouse model of collagen-induced arthritis (CIA) with the aim of identifying a novel safe and effective biological for treating RA. This novel peptide significantly suppressed the induction and development of CIA, resulting in the suppression of synovial inflammation and cartilage degradation in vivo. Moreover, AESIS-1 regulated JAK/STAT3-mediated gene expression in vitro. In particular, the gene with the most significant change in expression was suppressor of cytokine signaling 3 (Socs3), which was enhanced 8-fold. Expression of the STAT3-specific inhibitor, Socs3, was obviously enhanced dose-dependently by AESIS-1 at both the mRNA and protein levels, resulting in a significant reduction of STAT3 phosphorylation in splenocytes from severe CIA mice. This indicated that AESIS-1 regulated STAT3 activity by upregulation of SOCS3 expression. Furthermore, IL-17 expression and the frequency of Th17 cells were considerably decreased by AESIS-1 in vivo and in vitro. Collectively, our data suggest that the novel synthetic peptide AESIS-1 could be an effective therapeutic for treating RA via the downregulation of STAT3 signaling.

The objective of this study was to investigate the effects of a hypodermic injectable solution comprised of an LPM LB meso solution containing Melissa officinalis L. leaf extract (LPM) on the lipogenesis in the 3T3-L1 cells line. The lipid accumulation measured by oil red o staining in the 3T3-L1 adipocytes treated with LPM, which was reduced in a dose dependent manner and showed 91.7 to 62.9% compared to control group. Its effectiveness with a 50% solution was significantly higher than the hydroxycitric acid (positive control) treatment without showing cell cytotoxicity. In a quantitative real-time PCR, it was demonstrated that the LPM treatment appeared to upregulate the mRNA expression of the adipogenesis-related genes, which included the peroxisome proliferator-activated receptor gamma (50% concentration) while down-regulating the CCAATenhancer binding protein alpha (50% concentration) and the sterol regulatory element-binding protein 1c (10, 25, and 50% concentrations). The results from the current study suggest that the LPM could be useful biomaterials that can inhibit obesity in the 3T3-L1 cells, which could possibly be by regulating the specific adipogenic gene transcription factors.

Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TAT-Cre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TAT-Cre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TAT-Cre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.

Diets high in red meats, particularly meats cooked at high temperature, increase the risk of colon cancer due to a production of heterocyclic aromatic amines (HAAs). Of the identified HAAs, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is the most mass abundant colon carcinogen in charred meat or fish. Here, we comprehensively examined sex-dependent colon transcriptome signatures in response to PhIP treatment to identify biological discrepancies. Eight-week-old male and female C57BL/6N mice were intraperitoneally injected with PhIP (10 mg/kg of body weight) and colon tissues were harvested 24 h after PhIP injection, followed by colon transcriptomics analysis. A list of differentially expressed genes (DEGs) was utilized for computational bioinformatic analyses. Specifically, overrepresentation test using the Protein Analysis Through Evolutionary Relationships tool was carried out to annotate sex-dependent changes in transcriptome signatures after PhIP treatment. Additionally, the most significantly affected canonical pathways by PhIP treatment were predicted using the Ingenuity Pathway Analysis. As results, male and female mice presented different metabolic signatures in the colon transcriptome. In the male mice, oxidative phosphorylation in the mitochondrial respiratory chain was the pathway impacted the most; this might be due to a shortage of ATP for DNA repair. On the other hand, the female mice showed concurrent activation of lipolysis and adipogenesis. The present study provides the foundational information for future studies of PhIP effects on underlying sex-dependent mechanisms.