Members of the archaeal phylum Bathyarchaeota are widespread and abundant in the energy-deficient marine subsurface sediments. However, their life strategies have remained largely elusive. Here, we provide genetic evidence that some lineages of Bathyarchaeota are acetogens, being capable of homoacetogenesis, a metabolism so far restricted to the domain Bacteria. Metabolic reconstruction based on genomic bins assembled from the metagenome of deep-sea subsurface sediments shows that the metabolism of some lineages of Bathyarchaeota is similar to that of bona fide bacterial homoacetogens, by having pathways for acetogenesis and for the fermentative utilization of a variety of organic substrates. Heterologous expression and activity assay of the acetate kinase gene ack from Bathyarchaeota, demonstrate further the capability of these Bathyarchaeota to grow as acetogens. The presence and expression of bathyarchaeotal genes indicative of active acetogenesis was also confirmed in Peru Margin subsurface sediments where Bathyarchaeota are abundant. The analyses reveal that this ubiquitous and abundant subsurface archaeal group has adopted a versatile life strategy to make a living under energy-limiting conditions. These findings further expand the metabolic potential of Archaea and argue for a revision of the role of Archaea in the carbon cycle of marine sediments.

Early brain injury (EBI) plays a key role in determining the prognosis of patients suffering from subarachnoid hemorrhage (SAH). Resveratrol, a natural polyphenol, serves a neuroprotection function on EBI after SAH. However, the potential mechanism of resveratrol on EBI remains to be elucidated. Akt, also known as protein kinase B, and mammalian target of rapamycin (mTOR), the downstream protein of Akt, play key roles in cell survival and apoptosis, cell cycle regulation, and cellular protein homeostasis. In the present study, we examined the effect of resveratrol on EBI and their potential relationship with the Akt/mTOR pathway, autophagy, and apoptosis. Rats received intraperitoneal administration of resveratrol or vehicle immediately after establishing SAH model. We found that mortality and brain edema were significantly lower, whereas the neurological score was higher for resveratrol-treated rats. HE staining showed that resveratrol significantly reduced the neuronal pyknosis and swelling in the resveratrol-treated rats compared with SAH rats. The results were assessed by western blot, reverse transcription-PCR , and immunohistochemistry and immunofluorescence at 24 h after injury to determine changes in the expression of the Akt/mTOR signaling pathway, autophagy, and apoptosis proteins. Western blot analysis showed that the expression of beclin-1, LC3-II, LC3-II/LC3-I, and Bcl-2 was increased in resveratrol-treated rats, whereas the expression of p-Akt, p-mTOR, p62, cleaved caspase-3, caspase-9, and Bcl-2-associated X protein was decreased. Immunohistochemistry analysis of beclin-1, LC3-B treated with resveratrol alone or in combination with 3-methyladenine (autophagy inhibitor) suggested that resveratrol induced the autophagy process and the inhibitor blocked the occurrence of autophagy, and also increased the number of terminal deoxynucleotidyl transferase-mediated digoxigenin-DUTP-biotin nick-end labeling (+) cells. Taken together, these findings indicate that resveratrol exerts neuroprotective effects on EBI after SAH by regulating autophagy and apoptosis mediated by the Akt/mTOR pathway.

No abstract

No abstract

Human fibroblast-like synoviocytes play a vital role in joint synovial inflammation in rheumatoid arthritis (RA). Proinflammatory cytokines induce fibroblast-like synoviocyte activation and dysfunction. The inflammatory mediator Krüppel-like factor 4 is upregulated during inflammation and plays an important role in endothelial and macrophage activation during inflammation. However, the role of Krüppel-like factor 4 in fibroblast-like synoviocyte activation and RA inflammation remains to be defined. In this study, we identify the notion that Krüppel-like factor 4 is higher expressed in synovial tissues and fibroblast-like synoviocytes from RA patients than those from osteoarthritis patients. In vitro, the expression of Krüppel-like factor 4 in RA fibroblast-like synoviocytes is induced by proinflammatory cytokine tumor necrosis factor-α. Overexpression of Krüppel-like factor 4 in RA fibroblast-like synoviocytes robustly induced interleukin-6 production in the presence or absence of tumor necrosis factor-α. Conversely, knockdown of Krüppel-like factor 4 markedly attenuated interleukin-6 production in the presence or absence of tumor necrosis factor-α. Krüppel-like factor 4 not only can bind to and activate the interleukin-6 promoter, but also may interact directly with nuclear factor-kappa B. These results suggest that Krüppel-like factor 4 may act as a transcription factor mediating the activation of fibroblast-like synoviocytes in RA by inducing interleukin-6 expression in response to tumor necrosis factor-α.