[Preliminary study of the relationship between novel coronavirus pneumonia and liver function damage: a multicenter study]

Objective: To analyze the clinical characteristics of cases of novel coronavirus pneumonia and a preliminary study to explore the relationship between different clinical classification and liver damage. Methods: Consecutively confirmed novel coronavirus infection cases admitted to seven designated hospitals during January 23, 2020 to February 8, 2020 were included. Clinical classification (mild, moderate, severe, and critical) was carried out according to the diagnosis and treatment program of novel coronavirus pneumonia (Trial Fifth Edition) issued by the National Health Commission. The research data were analyzed using SPSS19.0 statistical software. Quantitative data were expressed as median (interquartile range), and qualitative data were expressed as frequency and rate. Results: 32 confirmed cases that met the inclusion criteria were included. 28 cases were of mild or moderate type (87.50%), and four cases (12.50%) of severe or critical type. Four cases (12.5%) were combined with one underlying disease (bronchial asthma, coronary heart disease, malignant tumor, chronic kidney disease), and one case (3.13%) was simultaneously combined with high blood pressure and malignant tumor. The results of laboratory examination showed that the alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (ALB), and total bilirubin (TBil) for entire cohort were 26.98 (16.88 ~ 46.09) U/L and 24.75 (18.71 ~ 31.79) U/L, 39.00 (36.20 ~ 44.20) g/L and 16.40 (11.34 ~ 21.15) μmol/L, respectively. ALT, AST, ALB and TBil of the mild or moderate subgroups were 22.75 (16.31 ~ 37.25) U/L, 23.63 (18.71 ~ 26.50) U/L, 39.70 (36.50 ~ 46.10) g/L, and 15.95 (11.34 ~ 20.83) μmol/L, respectively. ALT, AST, ALB and TBil of the severe or critical subgroups were 60.25 (40.88 ~ 68.90) U/L, 37.00 (20.88 ~ 64.45) U/L, 35.75 (28.68 ~ 42.00) g/L, and 20.50 (11.28 ~ 25.00) μmol/L, respectively. Conclusion: The results of this multicenter retrospective study suggests that novel coronavirus pneumonia combined with liver damage is more likely to be caused by adverse drug reactions and systemic inflammation in severe patients receiving medical treatment. Therefore, liver function monitoring and evaluation should be strengthened during the treatment of such patients.

[The study of atmospheric particulate matters and IFN-γDNA methylation in CD4⁺ T cells from patients with AR children]

Objective:To investigate the possible effects of meteorological and environmental factors on AR of children and IFN-γgene specific DNA methylation levels in CD4⁺ T cells of patients with AR. Method:Undergoing follow-up on 35 pediatric AR patients (6-12 years). Data on daily sulfur dioxide (SO₂), nitrogen dioxide (NO₂), particulate matter of diameter smaller than 10 micrometer (PM-10) and particulate matter of diameter smaller than 2.5 micrometer (PM2.5), the average of ozone (O₃) per 8 hours was available as average values derived from the data of 6 state controlled monitoring stations distributed across Pudong district, Shanghai. We quantified IFN-γ (interferon-γ) gene specific DNA methylation levels in CD4⁺ T cells from 35 patients with AR and 30 healthy controls. mRNA levels of IFN-γ gene were measured by real-time reverse transcriptase-PCR. Methods of personal exposure assessment of PM2.5 and PM10 were measured. Result:Compared with control, IFN-γ promoter region was hypermethylated in AR CD4⁺ T cells (P<0.05). Of all observed CpG sites in IFN-γ promoter region, there were significant differences in CpG⁻²⁹⁹, CpG⁺¹¹⁹, CpG⁺¹⁶⁸ (P=0.004, P=0.029, P=0.035). IFN-γ mRNA expression was significantly increase in CD4⁺ T cells (P<0.05). The level of IFN-γ mRNA expression was negatively correlated to mean level of methylation in IFN-γ promoter region. After adjusting, level of long exposure PM2.5 was positively correlated with level of methylation in IFN-γ promoter region. Conclusion:Level of methylation in IFN-γ promoter region may be affected by long exposure PM2.5.

Molecular characterization and functional analysis of sheep thyroid transcription factor-1

Thyroid transcription factor-1 (TTF-1), a member of the Nkx2 family of homeodomain-containing proteins, is involved in binding to and in activating the promoters of several important genes in the thyroid, lungs, and brain, and in regulating expression of these tissue-specific genes. We investigated potential roles of sheep (Ovis aries) TTF-1 in regulating cell fate and organ morphogenesis and in controlling puberty and reproductive capability of females. We amplified and cloned the sheep TTF-1 full-length DNA for the first time, analyzed its functional domains and regions, predicted molecular structure of its homeodomain and DNA-binding sites, and examined its expression in pituitary, brain, thyroid gland, ovary, and hypothalamus. We found that sheep TTF-1 has a high degree of homologous identity with that of other mammals, and it has several important domains including domain N, DNA-binding domain, domain C, TN-domain, domain I, and NK2-SD. The DNA-binding domain of sheep TTF-1 has 10 potential DNA-binding sites and is a novel mammalian homeodomain that shows considerable sequence homology with the corresponding rat homeodomain. Several functional regions in sheep TTF-1 share high sequence identity with rat TTF-1, indicating that these regions may have the same activity as in the rat. Expression of TTF-1 in several specific tissues implies that sheep TTF-1 in involved in sheep sexual development and reproductive capability. These results suggest a role of sheep TTF-1 in enhancing sheep reproduction performance and we propose it as a candidate gene for selection.

Identification of a transparent mutant tiger barb Puntius tetrazona and its use for in vivo observation of a Pleistophora sp. (Microsporidia) infection

A transparent mutant tiger barb Puntius tetrazona was identified and characterized by its transparent body, which allows clear visualization of internal organs. Hybridization of this mutant with the albino variant produces a transparent and albinoid double phenotype, and the transparency of this mutant is controlled by a recessive allele. Light microscopic and ultrastructural examinations show that in contrast to normal individuals, transparent mutants lack iridophores, and light penetrates unimpeded through the body. Pleistophora sp. infection was observed in vivo, allowing live observation of parasite dissemination and the consequent pathological alterations in the fish body as well as the simultaneous acquisition of data on the dynamics and spatial pattern of pathogenic invasion. It is superior to common fish models, as dynamic experimental data can be obtained from individual fish.

Role of interaction of mannan-binding protein with meprins at the initial step of complement activation in ischemia/reperfusion injury to mouse kidney

Ischemia/reperfusion (I/R) is an important cause of acute renal failure. Recent studies have shown that the complement system mediated by the mannan-binding protein (MBP), which is a C-type serum lectin recognizing mannose, fucose and N-acetylglucosamine residues, plays a critical role in the pathogenesis of ischemic acute renal failure. MBP causes complement activation through the MBP lectin pathway and a resulting complement component, C3b, is accumulated on the brush borders of kidney proximal tubules in a renal I/R-operated mouse kidney. However, the initial step of the complement activation has not been studied extensively. We previously identified both meprins α and β, highly glycosylated zinc metalloproteases, localized on kidney proximal tubules as endogenous MBP ligands. In the present study, we demonstrated that serum-type MBP (S-MBP) and C3b were co-localized with meprins on both the cortex and the medulla in the renal I/R-operated mouse kidney. S-MBP was indicated to interact with meprins in vivo in the I/R-operated mouse kidney and was shown to initiate the complement activation through the interaction with meprins in vitro. Taken together, the present study strongly suggested that the binding of S-MBP to meprins triggers the complement activation through the lectin pathway and may cause the acute renal failure due to I/R on kidney transplantation and hemorrhagic shock.

Characterization of metallothioneins (MT-I and MT-II) in the yak

The cDNA-encoding sequences for yak metallothionein isoforms I (MT-I) and II (MT-II) were amplified and cloned by reverse-transcription PCR to characterize the nucleotide sequence and protein structure of metallothionein in the yak. The cDNA sequences of MT-I and MT-II were subjected to BLAST searching at the National Center for Biotechnology Information, and the results indicated that the nucleotide sequences of yak MT-I and MT-II, when compared among different species of mammals, are highly conserved. The yak open reading frames have a length of 183 nucleotides, which encode for yak MT-I and MT-II proteins of 61 AA, respectively. Analysis of hydrophobicity, trans-membrane region, and signal peptides suggested that metallothioneins of the yak are nonsecretory proteins. There were several conserved tripeptide sequences, such as C-X-C, C-C-X-C-C, and C-X-X-C (X designates AA excluding cysteine in MT-I and MT-II), and they are highly conserved in their evolution. By homologous comparative modeling, we predicted the molecular spatial structures of yak MT-I and MT-II, which are composed of alpha- and beta-domains that are linked by the conserved tripeptide Lys(30)-Lys(31)-Ser(32) (KKS).

The expression and the regulatory role of OX40 and 4-1BB heterodimer in activated human T cells

OX40 and 4-1BB are members of the tumor necrosis factor (TNF) family of costimulatory receptors whose signaling is important for differential immune responses mediated by CD4+ or CD8+ T cells. Although activated T cells may acquire OX40/4-1BB double-positive phenotype and signaling from each receptor is expected to influence cell functions, the relevance between OX40 and 4-1BB has never been investigated before. While we were investigating the expression of OX40 and 4-1BB on activated human T cells, we found that they colocalize. The study of receptor gene–transfected cells showed that both receptors coendocytose and the complex of OX40 and 4-1BB was detected by specific ligands or antibodies (Abs). The heterodimer of OX40 and 4-1BB was identified by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) under nonreduced conditions and was associated with the tumor receptor–associated factor (TRAF) family proteins in a unique manner. Furthermore, the stimulation of OX40/4-1BB rendered cells sensitive to apoptosis induced by TNF-α that accompanied reduced activation of nuclear factor-κB (NF-κB). Finally, the OX40/4-1BB stimulation repressed the mitogen response in activated CD25+CD4+ T cells and preactivated CD8+ T cells. Thus, the OX40/4-1BB heterodimer appears to represent a unique regulatory receptor in activated T cells.

The modulation of CD40 ligand signaling by transmembrane CD28 splice variant in human T cells

The role of CD40 ligand (CD40L)/CD40 signaling in T cell–dependent B cell differentiation and maturation has been amply documented. The mechanism of CD40 signaling in B cells has been well established, whereas the signaling mechanism of CD40L in T cell costimulation remains unknown. In this study we show that CD28i, a transmembrane splice variant of CD28 costimulatory receptor, complexes with CD40L in human T cells. The cross-linking of CD40L resulted in the coendocytosis of CD28i with CD40L. The tyrosine phosphorylation of CD28i followed the cross-linking of CD40L, and the overexpression of CD28i augmented the c-Jun NH₂-terminal kinase, p21-activated kinase 2, and nuclear factor κB activation. These data indicate that CD28i, by functioning as a signaling adaptor, transduces CD40L signaling as well as CD28 signaling in human T cells.

CD28 T cell costimulatory receptor function is negatively regulated by N-linked carbohydrates

CD28 is a cell surface glycoprotein expressed on T cells that modulates immune responses through its ability to transduce costimulatory signals. Even though nearly 50% of the molecular mass of CD28 is N-glycan, the physiological significance of CD28 glycosylation is at present unknown. In this report, we have investigated the function of hypoglycosylated wildtype CD28 and its splice variant, CD28i. When N-glycosylation was prevented through point mutations in N-glycosylation sites in CD28, or reduced by glycosidase inhibitors, the binding of CD28 to CD80 significantly increased. Stimulation of hypoglycosylated CD28 induced IL-2 promoter activity greater than that induced through the stimulation of wildtype CD28. Unlike hypoglycosylated wildtype CD28, hypoglycosylation of CD28i did not alter CD28i functions. Our data indicate that N-glycans of CD28 negatively regulate CD28/CD80 interactions, resulting in diminished CD28 signaling. It is also suggested that N-glycans regulate the density of CD28 clustering upon ligation with CD80/CD86. The results support the hypothesis that the N-glycosylation negatively regulates CD28-mediated T cell adhesion and costimulation.

Bone marrow-derived cells as progenitors of lung alveolar epithelium

We assessed the capacity of plastic-adherent cultured bone marrow cells to serve as precursors of differentiated parenchymal cells of the lung. By intravenously delivering lacZ-labeled cells into wild-type recipient mice after bleomycin-induced lung injury, we detected marrow-derived cells engrafted in recipient lung parenchyma as cells with the morphological and molecular phenotype of type I pneumocytes of the alveolar epithelium. At no time after marrow cell injection, did we detect any engraftment as type II pneumocytes. In addition, we found that cultured and fresh aspirates of bone marrow cells can express the type I pneumocyte markers, T1α and aquaporin-5. These observations challenge the current belief that adult alveolar type I epithelial cells invariably arise from local precursor cells and raise the possibility of using injected marrow-derived cells for therapy of lung diseases characterized by extensive alveolar damage.

TRAIL expression in vascular smooth muscle

TRAIL is a cell-associated tumor necrosis factor-related apoptosis-inducing ligand originally identified in immune cells. The ligand has the capacity to induce apoptosis after binding to cell surface receptors. To examine TRAIL expression in murine vascular tissue, we employed in situ hybridization and immunohistochemistry. In these studies, we found that TRAIL mRNA and protein were specifically localized throughout the medial smooth muscle cell layer of the pulmonary artery. Notably, a similar pattern of expression was observed in the mouse aorta. Consistent with these findings, we found that cultures of primary human aorta and pulmonary artery smooth muscle cells express abundant TRAIL mRNA and protein. We also found that these cells and endothelial cells undergo cell lysis in response to exogenous addition of TRAIL. Last, we confirmed that TRAIL specifically activated a death program by confirming poly(ADP ribose) polymerase cleavage. Overall, we believe that these findings are relevant to understanding the factors that regulate cell turnover in the vessel wall.

Molecular characterization of the mouse Fas ligand promoter in airway epithelial cells

Constitutively expressed Fas ligand in several distinct epithelial cell types appears to protect tissues by inducing apoptosis of Fas(+) immune cells during inflammatory reactions. To study the transcriptional regulation of Fas ligand gene in airway epithelial cells, a 618-bp 5'-flanking region of mouse Fas ligand gene was cloned, sequenced, and the transcriptional start site was determined by using 5'-RACE. Deletion analysis, gel mobility shift assays and site-directed mutagenesis indicated that a CCAAT box located -214 bp upstream from the transcription start site served as a major positive regulatory cis-element in an airway epithelial cell line. This element was not required for constitutive Fas ligand expression in Sertoli cells. Furthermore, the activity of the site did not involve the NF-Y protein complex or c/EBP protein family. UV-cross linking proteins to this element indicated that a approximately 23-kDa transcription factor bound to the Fas ligand promoter CCAAT box and, thus, likely plays an important role in the regulation of Fas ligand expression in airway epithelial cells.