Lung cancer (LC) is one of the most serious malignant tumors, which has the fastest growing morbidity and mortality worldwide. A role of the lung microbiota in LC pathogenesis has been analyzed, but a comparable role of the gut microbiota has not yet been investigated. In this study, the gut microbiota of 30 LC patients and 30 healthy controls were examined via next-generation sequencing of 16S rRNA and analyzed for diversity and biomarkers. We found that there was no decrease in significant microbial diversity (alpha diversity) in LC patients compared to controls ( P observed = 0.1422), while the composition (beta diversity) differed significantly between patients and controls (phylum [stress = 0.153], class [stress = 0.16], order [stress = 0.146], family [stress = 0.153]). Controls had a higher abundance of the bacterial phylum Actinobacteria and genus Bifidobacterium , while patients with LC showed elevated levels of Enterococcus . These bacteria were found as possible biomarkers for LC. A decline of normal function of the gut microbiome in LC patients was also observed. These results provide the basic guidance for a systematic, multilayered assessment of the role of the gut microbiome in LC, which has a promising potential for early prevention and targeted intervention.

Osteoarthritis is a common cause of functional deterioration in older adults and is an immense burden on the aging population. Altered chondrogenesis is the most important pathophysiological process involved in the development of osteoarthritis. However, the molecular mechanism underlying the regulation of chondrogenesis in patients with osteoarthritis requires further elucidation, particularly with respect to the role of microRNAs. MiR-21 expression in cartilage specimens was examined in 10 patients with knee osteoarthritis and 10 traumatic amputees. The effect of miR-21 on chondrogenesis was also investigated in a chondrocyte cell line. The effect of miR-21 on the expression of growth differentiation factor 5 (GDF-5) was further assessed by luciferase reporter assay and western blot. We found that endogenous miR-21 is upregulated in osteoarthritis patients, and overexpression of miR-21 could attenuate the process of chondrogenesis. Furthermore, we identified GDF-5 as the direct target of miR-21 during the regulation of chondrogenesis. Our data suggest that miR-21 has an important role in the pathogenesis of osteoarthritis and is a potential therapeutic target.

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