Obesity represents a major health challenge because it substantially increases the risk of metabolic diseases. Capsaicin, the major active ingredient of Capsicum spp., has been reported to possess anti-obesity activity. Hereon, the effect of capsaicin on glucose uptake and consumption in hepatocytes was extensively studied. Capsaicin was shown to accelerate the glucose uptake/consumption and the ATP production of hepatocytes. The elevation of intracellular Ca²⁺ was thought to be a potential mechanism. By transcriptome analysis, 78, 146 and 507 differentially expressed genes (DEGs) were identified between capsaicin and the control group for 4 h, 12 h and 24 h treatments. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that most of the DEGs were involved in canonical pathways, like MAPK and PI3K-AKT signaling pathways. Clustering analysis showed that many DEGs were associated with glucose and amino acid metabolism. The variation trend in genes related to glucose and amino acid metabolism (like CTH, VEGFA, PCK2 and IGFBP3) in the quantitative PCR (q-PCR) assay was consistent with the transcriptome data. These results demonstrated that capsaicin efficiently accelerated the glucose uptake and consumption of hepatocytes.

Protein components of C. militaris have been reported to possess various biological activities. In our previous research, a Cordyceps militaris-derived immunoregulatory protein (CMIP) was naturally isolated and showed the activity of inhibiting the metastasis of breast cancer cells. This study aimed to obtain recombinant CMIP (rCMIP) using recombinant expression and elucidate its ability to activate macrophages. Recombinant CMIP showed one band at approximately 15 kDa or 30 kDa, or two bands at 15 kDa and 30 kDa, under different denaturation conditions of electrophoresis. The cell binding assay showed that rCMIP selectively binds to the surface of macrophages. After adhesion, it did not induce the apoptosis of RAW 264.7 cells, but promoted their proliferation. Moreover, rCMIP significantly induced the expression of M1 macrophage polarization-related molecules. The mean fluorescence intensity (MFI) of CD 86 was enhanced by 2.1-fold and 3.2-fold under 0.64 μM and 1.6 μM of rCMIP treatment, respectively. Cytokines typically expressed in M1 macrophages, such as TNF-α, iNOS, IL-6, CCL 4, CCL 5 and CXCL 10, were also considerably induced by rCMIP, while the expression of cytokines in typical M2 macrophages, like Arg-1, CCL17 and CCL22, were not changed or slightly decreased. Under rCMIP treatment, the release of NO was also appreciably induced. In the present study, we reported cloning, expression and functional characterization of rCMIP, which was naturally isolated from the fruiting body of C. militaris in our previous study. The data imply that rCMIP possesses immunomodulatory activity in macrophages.