miR-590-5p affects chondrocyte proliferation, apoptosis, and inflammation by targeting FGF18 in osteoarthritis.

OBJECTIVE: To investigate the potential miRNA targeting FGF18, and its role in regulating the proliferation, apoptosis and inflammation in human primary chondrocytes. METHODS: The normal human chondrocytes were induced by IL-1ß to mimic OA in vitro. qPCR and Western blotting were performed to evaluate the expression of FGF18. Target Scan analysis was performed to predict the miRNA targeting FGF18. Then, the expression of miR-590-5p was quantified by qPCR in IL-1ß-induced chondrocytes. After transfection of miR-590-5p mimics or inhibitors, CCK-8 assay was conducted to determine the cell viability and apoptosis-related proteins, and cartilage degeneration related biomarkers were assayed by qPCR and Western blotting. The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 were determined by ELISA. The targeting relationship between miR-590-5p and FGF18 was assayed by luciferase reporter assay in IL-1ß-induced chondrocytes. RESULTS: Target Scan analysis predicted that FGF18 is directly targeted by miR-590-5p. miR-590-5p was up-regulated, whereas FGF18 expression was inhibited in IL-1ß-induced chondrocytes. miR-590-5p mimics reduced the expression of FGF18 protein, inhibited the cell viability of chondrocytes, and promoted secretion of inflammatory factors in chondrocytes, while miR-590-5p inhibitors increased FGF18 levels in IL-1ß-treated chondrocytes. Furthermore, expression of inflammatory factors in chondrocytes was reduced by miR-590-5p inhibitors. The luciferase reporter assay showed that miR-590-5p could target FGF18. CONCLUSIONS: miR-590-5p promotes OA progression by targeting FGF18, which serves as a potential therapeutic target for OA.

Evidence for immortality and autonomy in animal cancer models is often not provided, which causes confusion on key issues of cancer biology.

Modern research into carcinogenesis has undergone three phases. Surgeons and pathologists started the first phase roughly 250 years ago, establishing morphological traits of tumors for pathologic diagnosis, and setting immortality and autonomy as indispensable criteria for neoplasms. A century ago, medical doctors, biologists and chemists started to enhance "experimental cancer research" by establishing many animal models of chemical-induced carcinogenesis for studies of cellular mechanisms. In this second phase, the two-hit theory and stepwise carcinogenesis of "initiation-promotion" or "initiation-promotion-progression" were established, with an illustrious finding that outgrowths induced in animals depend on the inducers, and thus are not authentically neoplastic, until late stages. The last 40 years are the third incarnation, molecular biologists have gradually dominated the carcinogenesis research fraternity and have established numerous genetically-modified animal models of carcinogenesis. However, evidence has not been provided for immortality and autonomy of the lesions from most of these models. Probably, many lesions had already been collected from animals for analyses of molecular mechanisms of "cancer" before the lesions became autonomous. We herein review the monumental work of many predecessors to reinforce that evidence for immortality and autonomy is essential for confirming a neoplastic nature. We extrapolate that immortality and autonomy are established early during sporadic human carcinogenesis, unlike the late establishment in most animal models. It is imperative to resume many forerunners' work by determining the genetic bases for initiation, promotion and progression, the genetic bases for immortality and autonomy, and which animal models are, in fact, good for identifying such genetic bases.

Mussel polysaccharide α-D-glucan (MP-A) protects against non-alcoholic fatty liver disease via maintaining the homeostasis of gut microbiota and regulating related gut-liver axis signaling pathways.

We isolated and characterized a Mussel polysaccharide, α-D-glucan (MP-A), from Mytilus coruscus earlier. In this work, the pharmacological activity and mechanisms of MP-A as an oral supplement for non-alcoholic fatty liver disease (NAFLD) were explored. High fat diet (HFD) was utilized to induce NAFLD in Sprague Dawley male rats and MP-A (0.6 g/kg) was supplemented for 4 weeks. The results showed that MP-A supplementation reduced blood lipid levels, intrahepatic lipid accumulation and NAFLD activity score in HFD-fed rats. Additionally, the analysis of 16S rDNA sequencing on gut microbiota samples revealed that HFD could induce microbial dysbiosis. However, MP-A supplementation could remodel gut microbiota structure, inhibit LPS-TLR4-NF-κB pathway activation, and restrain subsequent inflammation factors secretion. Furthermore, MP-A regulated the lipid metabolism by promoting the production of short chain fatty acids and suppressing PPAR γ and SREBP-1c expression. Our results support that MP-A can prevent against NAFLD and act as an oral supplementation for hepatoprotection via modulating gut microbiota and related gut-liver axis signaling pathways.

Lower range of molecular weight of xanthan gum inhibits apoptosis of chondrocytes through MAPK signaling pathways.

LRWXG has previously been reported to have a protective effect on chondrocytes, preventing apoptosis induced by oxidative stress. In this study, we were aimed at determining whether LRWXG exerts its anti-apoptotic activity through the MAPK signaling pathways in chondrocytes. Our results show that, at the cellular level, apoptosis of chondrocytes in the groups treated by LRWXG decreases compared with groups treated by inhibitors alone and model group under conditions of oxidative stress in a dose-dependent manner. Mechanistically at the molecular level, LRWXG regulates the MAPK pathway induced by oxidative stress: The levels of phosphorylation of JNK and p38 proteins in the groups treated by LRWXG are lower than model group, while compared with corresponding groups of inhibitors, there are no significant difference; For other related proteins, LRWXG reduces the levels of the apoptosis-related proteins BAX and cleaved caspase-3, and increases the level of anti-apoptotic protein BCL2. In addition, LRWXG can significantly reduce the levels of inflammatory-related factors such as COX2, PEG2, TNFα and IL1ß, and inhibits the expression of MMPs, increasing the content of type II collagen. The results of this research strongly suggest that LRWXG exerts its anti-apoptotic activity via regulating the MAPK signaling pathways in vitro.

Evaluating the Remote Control of Programmed Cell Death, with or without a Compensatory Cell Proliferation.

Organisms and their different component levels, whether organelle, cellular or other, come by birth and go by death, and the deaths are often balanced by new births. Evolution on the one hand has built demise program(s) in cells of organisms but on the other hand has established external controls on the program(s). For instance, evolution has established death program(s) in animal cells so that the cells can, when it is needed, commit apoptosis or senescent death (SD) in physiological situations and stress-induced cell death (SICD) in pathological situations. However, these programmed cell deaths are not predominantly regulated by the cells that do the dying but, instead, are controlled externally and remotely by the cells' superior(s), i.e. their host tissue or organ or even the animal's body. Currently, it is still unclear whether a cell has only one death program or has several programs respectively controlling SD, apoptosis and SICD. In animals, apoptosis exterminates, in a physiological manner, healthy but no-longer needed cells to avoid cell redundancy, whereas suicidal SD and SICD, like homicidal necrosis, terminate ill but useful cells, which may be followed by regeneration of the live cells and by scar formation to heal the damaged organ or tissue. Therefore, "who dies" clearly differentiates apoptosis from SD, SICD and necrosis. In animals, apoptosis can occur only in those cell types that retain a lifelong ability of proliferation and never occurs in those cell types that can no longer replicate in adulthood. In cancer cells, SICD is strengthened, apoptosis is dramatically weakened while SD has been lost. Most published studies professed to be about apoptosis are actually about SICD, which has four basic and well-articulated pathways involving caspases or involving pathological alterations in the mitochondria, endoplasmic reticula, or lysosomes.

Lower range of molecular weight of xanthan gum inhibits cartilage matrix destruction via intrinsic bax-mitochondria cytochrome c-caspase pathway.

We have previously reported an application of lower range of molecular weight of xanthan gum (LRWXG) for inhibiting cartilage matrix destruction and preventing mitochondrial damage in rabbit osteoarthritis (OA) model. However, whether LRWXG exerts its anti-OA activity through intrinsic bax-mitochondria cytochrome c-caspase signaling pathway in OA still requires further study. To address this problem, the OA model was induced by anterior cruciate ligament transection (ACLT) in rabbit and then treated with LRWXG. The results showed that LRWXG could inhibit the loss of collagen in cartilage matrix, protect trabecular bone in subchondral, decrease the apoptosis of chondrocytes, down-regulate the expressions of active caspase-9, active caspase-3 and bax, and up-regulate the expression of bcl-2. In addition, LRWXG could up-regulate the expression of cyt-c in mitochondria, while down-regulate the expression of cyt-c in cytoplasm. These findings show that LRWXG inhibits cartilage degradation via an intrinsic bax-mitochondria cytochrome c-caspase pathway in OA.

The well-accepted notion that gene amplification contributes to increased expression still remains, after all these years, a reasonable but unproven assumption.

"Gene amplification causes overexpression" is a longstanding and well-accepted concept in cancer genetics. However, raking the whole literature, we find only statistical analyses showing a positive correlation between gene copy number and expression level, but do not find convincing experimental corroboration for this notion, for most of the amplified oncogenes in cancers. Since an association does not need to be an actual causal relation, in our opinion, this widespread notion still remains a reasonable but unproven assumption awaiting experimental verification.