[Nutritional support for critically ill patients with COVID-19].

Nutritional support is an indispensable part in the treatment of critically ill patients with coronavirus disease 2019 (COVID-19). Critically ill COVID-19 patients are often in a state of high inflammation, high stress, high catabolism, and their energy consumption increases significantly. All critically ill patients with COVID-19 should be screened for nutritional risk with NRS-2002 or Nutric tool in the early stage. If there is a risk of malnutrition, subjective global assessment (SGA) or Global Leadership Initiative on Malnutrition (GLIM) are further used for malnutrition assessment. After assessment, the daily energy, protein, electrolyte and liquid quantity needed by the patients should be determined according to the actual condition. Then, according to the degree of gastrointestinal function impairment in patients, the oral nutrition supplement, enteral nutrition, parenteral nutrition or their combination are selected for nutritional support. For patients with normal gastrointestinal function who require prone position ventilation or receive extracorporeal membrane oxygenation (ECMO) treatment, enteral nutrition is recommended as the first choice. In addition, in the process of nutrition implementation, it is necessary to closely monitor the adverse reactions such as abdominal distention, diarrhea, regurgitation, phlebitis and liver function damage, timely adjust the nutrition program to ensure the smooth implementation of nutritional support. Based on the metabolic characteristics of critically ill patients with COVID-19, this paper makes a summary and suggestion on the following perspectives such as nutritional risk screening and assessment, target amount of nutritional treatment, nutritional intervention and treatment, nutritional support of special populations, and common adverse reactions in nutritional support treatment, so as to provide reference for individualized nutritional support therapy of critically ill patients with COVID-19.

Expression of Halo-hFGF18 and study of its effect on differentiation of ATDC5 cells.

Fibroblast growth factor 18 (FGF18) is a member of the fibroblast growth factor family and important in cartilage growth and development. However, the mechanism by which FGF18 mediates its biological functions is still unclear. In our study, we expressed the rhFGF18 protein fused to a HaloTag, (Halo-rhFGF18). MTT assay results indicated that both rhFGF18 and Halo-rhFGF18 have similar biological activities in NIH3T3 cells. However, basic FGF and acidic FGF were more potent than both rhFGF18 and Halo-rhFGF18. Confocal imaging data indicated that the red fluorescence labeled Halo-rhFGF18 strongly bound to ATDC5 cells and stimulated their proliferation and differentiation, which suggests that glycosaminoglycans may be involved in mediating the biological effects of rhFGF18 in ATDC5 cells. Moreover, western blot results demonstrated that, in ATDC5 cells, ERK1/2 signaling is activated upon stimulation with rhFGF18. Our results may open doors for the use of rhFGF18 as a drug to promote cartilage growth.

Highly efficient production of functional recombinant human fibroblast growth factor 22 in E. coli and its protective effects on H2O2-lesioned L02 cells.

In the 22 member mammalian FGF family, FGF22 belongs to FGF7 subfamily, and its effects are largely confined to the brain and skin. To explore the functions of FGF22 on other tissues and develop a large-scale production of recombinant human FGF22 (rhFGF22) without a fusion tag, a plasmid encoding human FGF22 (pET3a-rhFGF22) was used to express rhFGF22 in E. coli BL21 (DE3) pLysS. A large amount of rhFGF22 inclusion body protein was obtained. A two-step denaturing method successfully solubilized rhFGF22, and it was refolded and then purified in one step via heparin affinity chromatography. A yield of 105 mg rhFGF22 with a purity of up to 95% was obtained from 100 g wet bacteria. It was found that the rhFGF22 had biological activity, since it effectively attenuated H2O2-induced human hepatic L02 cell death. Analysis by qRT-PCR and Western blot demonstrated that rhFGF22 protects L02 cells from H2O2-induced oxidative damage via suppression of mitochondrial apoptosis pathways. In conclusion, the strategy described in this paper may provide a novel means to solve the production of insoluble rhFGF22 and shine new light on its translational potential.

FGF18 inhibits MC3T3­E1 cell osteogenic differentiation via the ERK signaling pathway.

Fibroblast growth factor (FGF) 18 is a member of the FGF family and serves a key role in skeletal growth and development. The present study investigated the effect of FGF18 on pre­osteoblast MC3T3-E1 cells and the signaling pathways involved by performing an alkaline phosphatase (ALP) assay and reverse transcription­quantitative polymerase chain reaction. MC3T3­E1 cells incubated in a culture medium supplemented with FGF18 exhibited increased viability when compared with the untreated control cells. In addition, ALP activity was decreased in MC3T3­E1 cells treated with FGF18 plus an osteogenic medium (OM) for 7 and 14 days when compared with untreated and OM­treated controls. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) results demonstrated that the expression of osteoblastic­associated genes was significantly repressed in FGF18 plus OM­treated MC3T3­E1 cells, including ALP, collagen type I, osteocalcin, bone sialo protein and osterix. These results suggested that the expression levels of genes associated with osteogenesis were mainly repressed. In addition, combined treatment of MC3T3­E1 cells with OM and FGF18 led to a significant reduction in mineral deposition when compared with the OM­only treated group. Furthermore, FGF18 activated the extracellular signal­regulated kinase pathway in MC3T3­E1 cells, which may have been responsible for the observed decrease in the expression of osteoblastic­associated genes. In conclusion, the results suggest that FGF18 may be involved in MC3T3­E1 cell proliferation and osteoblastic differentiation.

High-yield of biologically active recombinant human fibroblast growth factor-16 in E. coli and its mechanism of proliferation in NCL-H460 cells.

Fibroblast growth factor-16 (FGF16) is a member of FGF9 subfamily, which plays key role in promoting mitosis and cell survival, and also involved in embryonic development, cell growth, tissue repair, morphogenesis, tumor growth, and invasion. However, the successful high-yield purification of recombinant human fibroblast growth factor-16 (rhFGF16) protein has not been reported. In addition, lung cancer is a major cause of cancer-related deaths, which threats people's lives and its incidence has continued to rise. Learning pathways or proteins, which involved in lung tumor progression will contribute to the development of early diagnosis and targeted therapy. FGF16 promoted proliferation and invasion behavior of SKOV-3 ovarian cancer cells, whose function may be similar in lung cancer. The hFGF16 was cloned into pET-3d and expressed in Escherichia coli BL21 (DE3) pLysS. Finally, obtained two forms of FGF16 that exhibited remarkable biological activity and the purity is over 95%, meanwhile, the yield of soluble 130 mg/100 g and insoluble 240 mg/100 g. Experiments demonstrated FGF16 could promote proliferation of NCL-H460 cells by activating Akt, Erk1/2, and p38 MAPK signaling, whereas JNK had no significant effect. In total, this optimized expression strategy enables significant quantity and activity of rhFGF16, thereby meeting its further pharmacological and clinical usages.

Fibroblast growth factor 18 promotes proliferation and migration of H460 cells via the ERK and p38 signaling pathways.

Recently, fibroblast growth factor 18 (FGF18) expression was reported to be upregulated in colon cancer and ovarian cancer, and increased expression of FGF18 mRNA and protein is associated with tumor progression and poor overall survival in patients; however, its role in lung cancer remains to be explored. In the present study, the effect and underlying molecular mechanisms of FGF18 on H460 cells were investigated. Cell proliferation and cell cycle alterations were detected using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and flow cytometry. A wound healing assay was conducted to detect cell migration. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to measure extracellular signal-regulated kinase (ERK), p38 and matrix metalloproteinase 26 (MMP26) expression. Knockdown of FGF18 using short interfering RNA (siRNA-FGF18) suppressed H460 cell proliferation, inhibited cell migration via the downregulation of MMP26 levels, with siRNA-FGF18 additionally inhibiting the ERK and p38 signaling pathway. The present study indicates that FGF18 serves an essential role in the growth and migration of non-small cell lung cancer (NSCLC) cells by regulating the ERK, p38 signaling pathways and MMP26 protein levels, suggesting that FGF18 may be a potential molecular drug target for the treatment NSCLC.

High production in E. coli of biologically active recombinant human fibroblast growth factor 20 and its neuroprotective effects.

Fibroblast growth factor 20 (FGF20) has a wide range of biological activities; its expression is most pronounced in neural tissues where it has functions in development and neuroprotection. Given these activities, interest in the clinical applications of FGF20 is rising, which will lead to increasing demand for active recombinant human FGF20 (rhFGF20). To improve the production of rhFGF20, an artificial gene encoding fgf20 was cloned into pET3a and expressed in E. coli BL21(DE3)pLysS. By optimizing induction conditions, we successfully induced large amounts of insoluble rhFGF20. Following solubilization and refolding of the rhFGF20 from inclusion bodies, it was purified by HiTrap heparin affinity chromatography to a purity of over 96% with a yield of 218 mg rhFGF20/100 g wet cells. The purified rhFGF20 could stimulate proliferation of both NIH 3T3 cells and PC-12 cells, measured by the MTT assay. In a model of Aß25-35-induced apoptosis on PC-12 cells, rhFGF20 had a clear protective effect. RT-PCR and Western blot analysis of apoptosis-related genes and proteins revealed that the FGF20-derived protective mechanism was likely due to the relief of endoplasmic reticulum stress (ER stress). In conclusion, the approach described here may be a better means to produce active rhFGF20 in good quantity, thereby allowing for its future pharmacological and clinical use.

Expression of functional recombinant human fibroblast growth factor 8b and its protective effects on MPP⁺-lesioned PC12 cells.

Human fibroblast growth factor 8b (FGF8b) was expressed based on a baculovirus expression vector system (BEVS) and identified as having a protective effect on Parkinson's disease. Immunoblotting demonstrated that rhFGF8b proteins were recognized by a human anti-FGF8b antibody. The multiplicity of infection and timing of harvest had a significant effect on protein yield and protein quality. Our results indicated that the rhFGF8b was first detectable at 36 h postinfection and reached a maximum at 60 h. A multiplicity of infection (MOI) of 8 pfu/mL was suitable for harvest. The target protein was purified by heparin-affinity chromatography. In vitro methylthiazol tetrazolium (MTT) assays demonstrated that the purified rhFGF8b could significantly stimulate proliferation of NIH3T3 cells. Furthermore, to elucidate the effect of rhFGF8b on Parkinson's disease, we used FGF8b pretreatment on a cell model of Parkinson's disease. The results indicated that rhFGF8b prevented necrosis and apoptosis of 1-METHYL-4-phenyl pyridine (MPP(+)) treated PC12 cells. Moreover, the effect of FGF8b on messenger RNA (mRNA) levels of apoptosis and ERS genes was investigated to clarify the molecular mechanisms of FGF8b. The results suggest that FGF8b exerts neuroprotective effects by alleviating endoplasmic reticulum (ER) stress during PD. These results suggest that FGF8b may be a promising candidate therapeutic drug for neurodegenerative diseases related to ER stress.