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Sirtuin6 (SIRT6), a member of the sirtuins protein family, plays multiple complex roles in cancer. Here, we report that elevated SIRT6 expression was correlated with clinicopathological parameters such as T and N classification in non-small cell lung cancer (NSCLC) patient tumors. SIRT6 overexpression in NSCLC cell lines increased extracellular signal-regulated kinase (p-ERK)1/2 phosphorylation, activated matrix metalloproteinase 9 (MMP9) and promoted tumor cell migration and invasion. Upon treatment with a specific mitogen-activated protein kinase (MEK) 1/2 inhibitor, these effects were abolished. Our results demonstrate SIRT6 upregulation in NSCLC for the first time and suggest a functional role for SIRT6 in promoting migration and invasion through ERK1/2/MMP9 signaling. SIRT6 may serve as a potential therapeutic target in NSCLC and its utility as a prognostic indicator warrants further study.

The lipid droplet (LD) is a cellular organelle that stores neutral lipids in cells and has been linked with metabolic disorders. Caenorhabditis elegans has many characteristics which make it an excellent animal model for studying LDs. However, unlike in mammalian cells, no LD structure-like/resident proteins have been identified in C. elegans, which has limited the utility of this model for the study of lipid storage and metabolism. Herein based on three lines of evidence, we identified that MDT-28 and DHS-3 previously identified in C. elegans LD pro-teome were two LD structure-like/resident proteins. First, MDT-28 and DHS-3 were found to be the two most abundant LD proteins in the worm. Second, the proteins were specifically localized to LDs and we identified the domains responsible for this targeting in both proteins. Third and most importantly, the depletion of MDT-28 induced LD clustering while DHS-3 deletion reduced triacylglycerol content (TAG). We further characterized the proteins finding that MDT-28 was ubiquitously expressed in the intestine, muscle, hypodermis, and embryos, whereas DHS-3 was expressed mainly in intestinal cells. Together, these two LD structure-like/resident proteins provide a basis for future mechanistic studies into the dynamics and functions of LDs in C. elegans.

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Background The lack of knowledge regarding the pathogenesis and host immune response during SARS-CoV-2 infection has limited the development of effective treatments. Thus, we longitudinally investigated the dynamic changes in peripheral blood lymphocyte subsets and parallel changes in cytokine levels in COVID-19 patients with different disease severities to further address disease pathogenesis. Methods A total of 67 patients (10 moderate, 38 severe and 19 critical cases) with COVID-19 admitted to a tertiary care hospital in Wuhan from February 8th to April 6th, 2020 were retrospectively studied. Dynamic data of lymphocyte subsets and inflammatory cytokines were collected. Results On admission, compared with moderate cases, severe and critical cases showed significantly decreased levels of total lymphocytes, T lymphocytes, CD4+ T cells, CD8+ T cells, B cells and NK cells. IL-6 and IL-10 were significantly higher in the critical group. During the following hospitalization period, most of the lymphocyte subsets in the critical group began to recover to levels comparable to those in the severe group from the fourth week after illness onset, except for NK cells, which recovered after the sixth week. A sustained decrease in the lymphocyte subsets and an increase in IL-6 and IL-10 were observed in the nonsurvivors until death. There was a strong negative correlation between IL-6 and IL-10 and total lymphocytes, T lymphocytes, CD4+ T cells, CD8+ T cells and NK cells. Conclusions A sustained decrease in lymphocyte subsets, especially CD4+ T cells and NK cells, interacting with proinflammatory cytokine storms was associated with severe disease and poor prognosis in COVID-19.

Background Acute fibrinous and organizing pneumonia (AFOP) is a rare histologic interstitial pneumonia pattern characterized by the intra-alveolar fibrin deposition and organizing pneumonia. Its clinical characteristics are still not well known and there is no consensus on treatment yet. Case presentation We report two female cases in their fifties diagnosed with AFOP confirmed by a second lung biopsy. Case 1 was idiopathic AFOP with manifestation of 6-week fever, dyspnea, and cough, while case 2 was secondary to systemic lupus erythematosus and fever was the major symptom. Their chest CT scans revealed bilateral multiple consolidations, predominantly in the lower lobes. Both cases were initially diagnosed with pneumonia, but did not improve after treatment with broad-spectrum antibiotics. In both cases, transbronchial biopsy and bronchoalveolar lavage fluid examination were inconclusive and the pathological diagnosis was confirmed by percutaneous lung biopsy. Both patients had a good clinical response to prednisone. Conclusions We report two rare AFOP cases to highlight the importance of awareness of this disease. We further perform the most comprehensive review to date in AFOP, including 150 patients since 2002. Consolidation was the most common imaging pattern, followed by ground-glass opacity and nodules. A lung biopsy is required for a definitive diagnosis. Corticosteroids is recommended as the most effective therapy, but treatment options should depend on the etiology and disease severity.

Lipid droplets (LDs) are the main fat storing sites in almost all species from bacteria to humans. The perilipin family has been found as LD proteins in mammals, Drosophila, and a couple of slime molds, but no bacterial LD proteins containing sequence conservation were identified. In this study, we reported that the hydroxysteroid dehydrogenase (HSD) family was found on LDs across all organisms by LD proteomic analysis. Imaging experiments confirmed LD targeting of three representative HSD proteins including ro01416 in RHA1, DHS-3 in C. elegans, and 17β-HSD11 in human cells. In C. elegans, 17β-HSD11 family proteins (DHS-3, DHS-4 and DHS-19) were localized on LDs in distinct tissues. In intestinal cells of C. elegans, DHS-3 targeted to cytoplasmic LDs, while DHS-9 labeled nuclear LDs. Furthermore, the N-terminal hydrophobic domains of 17β-HSD11 family were necessary for their targeting to LDs. Last, 17β-HSD11 family proteins induced LD aggregation, and deletion of DHS-3 in C. elegans caused lipid decrease. Independent of their presumptive catalytic sites, 17β-HSD11 family proteins regulated LD dynamics and lipid metabolism through affecting the LD-associated ATGL, which was conserved between C. elegans and humans. Together, these findings for HSDs provide a new insight not only into the mechanistic studies of the dynamics and functions of LDs in multiple organisms, but also into understanding the evolutionary history of the organelle.

CUE domain-containing 2 (CUEDC2) is a multi-functional protein, which regulates cell cycle, growth factor signaling and inflammation. We found that CUEDC2 was low in lung adenocarcinoma cell lines and lung adenocarcinoma tissues at both mRNA and protein levels. Low levels of CUEDC2 were correlated with a shorter survival time in patients with lung adenocarcinoma (p = 0.004). CUEDC2 expression was correlated with tumor T classification (P = 0.001) at clinical stage (P = 0.001) and tumor size (P = 0.033). Multivariate analysis suggested that CUEDC2 expression is an independent prognostic indicator for patients with lung adenocarcinoma. Ectopic expression of CUEDC2 decreased cell proliferation in vitro and inhibited tumor growth in nude mice in vivo. Knockdown of endogenous CUEDC2 by short hairpin RNAs (shRNAs) increased tumor growth. Inhibition of proliferation by CUEDC2 was associated with inactivation of the PI3K/Akt pathway, induction of p21 and down-regulation of cyclin D1. Our results suggest that decreased expression of CUEDC2 contributes to tumor growth in lung adenocarcinoma, leading to a poor clinical outcome.