Nur77 induced by HIF-1α mediates vascular remodeling in hypoxic pulmonary hypertension.

Nur77 is a member of the NR4A subfamily of orphan nuclear receptors that is expressed and has a function within the immune system. This study aimed to investigate the role of Nur77 in hypoxic pulmonary hypertension. SPF male SD rats were exposed in hypobaric chamber simulating 5000 m high altitude for 0, 3, 7, 14, 21 or 28 days. Rat pulmonary artery smooth muscle cells (RPASMCs) were cultured under normoxic conditions (5% CO2-95% ambient air) or hypoxic conditions (5% O2 for 6 h, 12 h, 24 h, 48 h). Hypoxic rats developed pulmonary arterial remodeling and right ventricular hypertrophy with significantly increased pulmonary arterial pressure. The levels of Nur77, HIF-1α and PNCA were upregulated in pulmonary arterial smooth muscle from hypoxic rats. Silencing of either Nur77 or HIF-1α attenuated hypoxia-induced proliferation. Silencing of HIF-1α down-regulated Nur77 protein level, but Nur77 silence did not reduce HIF-1α. Nur77 was not con-immunoprecipitated with HIF-1α. This study demonstrated that Nur77 acted as a downstream regulator of HIF-1α under hypoxia, and plays a critical role in the hypoxia-induced pulmonary vascular remodeling, which is regulated by HIF-1α. Nur77 maybe a novel target of HPH therapy.

Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells.

BACKGROUND: Thymosin alpha 1 (Tα1) had been used in the treatment of viral infections as an immune response modifier for many years. However, clinical benefits and the mechanism of Tα1 treatment for COVID-19 patients are still unclear. METHODS: We retrospectively reviewed the clinical outcomes of 76 severe COVID-19 cases admitted to 2 hospitals in Wuhan, China, from December 2019 to March 2020. The thymus output in peripheral blood mononuclear cells from COVID-19 patients was measured by T-cell receptor excision circles (TRECs). The levels of T-cell exhaustion markers programmed death-1 (PD-1) and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) on CD8+ T cells were detected by flow cytometry. RESULTS: Compared with the untreated group, Tα1 treatment significantly reduced the mortality of severe COVID-19 patients (11.11% vs 30.00%, P = .044). Tα1 enhanced blood T-cell numbers in COVID-19 patients with severe lymphocytopenia. Under such conditions, Tα1 also successfully restored CD8+ and CD4+ T-cell numbers in elderly patients. Meanwhile, Tα1 reduced PD-1 and Tim-3 expression on CD8+ T cells from severe COVID-19 patients compared with untreated cases. It is of note that restoration of lymphocytopenia and acute exhaustion of T cells were roughly parallel to the rise of TRECs. CONCLUSIONS: Tα1 treatment significantly reduced mortality of severe COVID-19 patients. COVID-19 patients with counts of CD8+ T cells or CD4+ T cells in circulation less than 400/µL or 650/µL, respectively, gained more benefits from Tα1. Tα1 reversed T-cell exhaustion and recovered immune reconstitution through promoting thymus output during severe acute respiratory syndrome-coronavirus 2 infection.

Acute Penicillium marneffei infection stimulates host M1/M2a macrophages polarization in BALB/C mice.

BACKGROUND: Penicillium marneffei (P. marneffei) is a thermally dimorphic fungus pathogen that causes fatal infection. Alveolar macrophages are innate immune cells that have critical roles in protection against pulmonary fungal pathogens and the macrophage polarization state has the potential to be a deciding factor in disease progression or resolution. The aim of this study was to investigate mouse alveolar macrophage polarization states during P. marneffei infection. RESULTS: We used enzyme-linked immunosorbent (ELISA) assays, quantitative real-time PCR (qRT-PCR), and Griess, arginase activity to evaluate the phenotypic markers of alveolar macrophages from BALB/C mice infected with P. marneffei. We then treated alveolar macrophages from infected mice with P. marneffei cytoplasmic yeast antigen (CYA) and investigated alveolar macrophage phenotypic markers in order to identify macrophage polarization in response to P. marneffei antigens. Our results showed: i) P. marneffei infection significantly enhanced the expression of classically activated macrophage (M1)-phenotypic markers (inducible nitric oxide synthase [iNOS] mRNA, nitric oxide [NO], interleukin-12 [IL-12], tumor necrosis factor-alpha [TNF-α]) and alternatively activated macrophage (M2a)-phenotypic markers (arginase1 [Arg1] mRNA, urea) during the second week post-infection. This significantly decreased during the fourth week post-infection. ii) During P. marneffei infection, CYA stimulation also significantly enhanced the expression of M1 and M2a-phenotypic markers, consistent with the results for P. marneffei infection and CYA stimulation preferentially induced M1 subtype. CONCLUSIONS: The data from the current study demonstrated that alveolar macrophage M1/M2a subtypes were present in host defense against acute P. marneffei infection and that CYA could mimic P. marneffei to induce a host immune response with enhanced M1 subtype. This could be useful for investigating the enhancement of host anti-P. marneffei immune responses and to provide novel ideas for prevention of P. marneffei-infection.

Case report: Streptococcus pneumoniae pneumonia characterized by diffuse centrilobular nodules in both lungs.

Background: Streptococcus pneumoniae (S. pneumoniae) is the most common pathogen in community-acquired pneumonia (CAP) and takes the form of lobar pneumonia as typical computed tomography (CT) findings. Various patterns of radiological manifestation have also been reported in patients with S. pneumoniae pneumonia; however, the appearance of diffuse centrilobular nodules in both lungs is rarely reported. Case presentation: We report the case of a patient with a history of chronic lymphocytic leukemia (CLL) for 9 years who presented with new-onset fever, cough, excess sputum, and shortness of breath for 1 week. He was given intravenous antibacterial (cephalosporin) treatment for 4 days, but his condition did not improve and dyspnea became more serious. The chest CT indicated diffuse centrilobular nodules in both lungs at admission. Patient's bronchoalveolar (BAL) fluid was sent for metagenomic next-generation sequencing, which only supported a diagnosis of S. pneumoniae infection. His condition improved gradually after antimicrobial treatment (moxifloxacin) and a follow-up CT showed that the diffuse centrilobular nodules in both lungs were absorbed completely. Conclusion: This case highlights a rare CT presentation of S. pneumoniae pneumonia that should alert clinicians, so as to avoid taking unnecessary treatment measures.

Clinical characteristics, risk factors, and cardiac manifestations of cancer patients with COVID-19.

Coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been associated with cardiovascular features, which may be deteriorated in patients with cancer. However, cardiac outcomes of cancer patients with COVID-19 have not been closely examined. We retrospectively assessed 1,244 patients with COVID-19 from February 1 to August 31, 2020 (140 cancer and 1,104 noncancer patients). Demographic and clinical data were obtained and compared between cancer and noncancer groups. Including the cardiac biomarkers, we also analyzed laboratory findings between these two groups. Risk factors for in-hospital mortality were identified by multivariable Cox regression models. For cancer group, 56% were in severe and critical status with more diabetes and immune deficiency, whereas the proportion was 10% for noncancer group. Patients with cancer had increased levels of leukocyte, neutrophil count, and blood urea nitrogen (BUN) (all P < 0.01), whereas lymphocyte count was significantly lower (P < 0.001). The most common solid tumor types were gastrointestinal cancer (26%), lung cancer (21%), and breast and reproductive cancer (both 19%). There is a rising for cardiac biomarkers, including pro-B-type natriuretic peptide (Pro-BNP), sensitive troponin I (cTnI), myoglobin (MYO), creatine kinase-MB (CK-MB), as well as D-Dimer in COVID-19 cancer population, especially in deceased subjects with cancer. The 30-day in-hospital mortality in cancer group was dramatically raised than that in noncancer group (12.9% vs. 4.0%, P < 0.01). In multivariable Cox regression models, fever, disease severity status, and underlying diseases were risk factors for mortality. COVID-19 patients with cancer relate to deteriorating conditions and poor cardiac outcomes accompanied by a high in-hospital mortality, which warrants more aggressive treatment.NEW & NOTEWORTHY Our study indicates that the 30-day mortality is higher in COVID-19 patients with cancer; more COVID-19 patients with cancer are in severe and critical status; age, respiratory rate, neutrophil count, AST, BUN, MYO, Pro-BNP, disease severity status, underlying diseases, and fever are risk factors for in-hospital mortality among COVID-19 cancer cases; COVID-19 patients with cancer display severely impaired myocardium, damaged heart function, and imbalanced homeostasis of coagulation; what is more, those with both cancer and CVD have more significantly increased Pro-BNP and D-Dimer level.

[Cigarette smoke extract down-regulates expression of histone deacetylase 2 and increases inflammatory cytokines releasing from murine C2C12 skeletal muscle myocytes].

OBJECTIVE: To observe changes of inflammatory mediators, histone deacetylase 2 (HDAC2) and nuclear factor κB (NF-κB) in murine C2C12 skeletal muscle myocytes after exposed to cigarette smoke. METHODS: Murine C2C12 skeletal muscle myocytes were cultured and treated with cigarette smoke extract (CSE). MTT assay was used to detect the effect of CSE on cell proliferation to determine appropriate concentration of CSE. The C2C12 cells cultured for 6-7 days were planted in six-well plates, and divided into control group, (6.25, 12.50, 25.0) mL/L CSE groups. The cells were cultured for 24 hours. The levels of interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) in the supernatant were measured by ELISA. The mRNA level of HDAC2 was determined by real-time quantitative PCR. The protein level of HDAC2 was detected by Western blotting. HDAC2/NF-κB compound was determined by the method of co-immunoprecipitation. RESULTS: MTT assay showed that CSE at the concentration of 50 mL/L inhibited proliferation of C2C12 cells. After 24-hour treatment with CSE, IL-8 and TNF-α releasing from C2C12 cells increased and the level of HDAC2 mRNA and protein were reduced, which were CSE dose-dependent. Co-immunoprecipitation confirmed that HDAC2/NF-κB compound existed in the CSE-exposed C2C12 cells. CONCLUSION: CSE can down-regulate the expression of HDAC2 and increase inflammatory cytokines releasing from C2C12 cells.

[Erythromycin restores oxidative stress-induced corticosteroid responsiveness of human THP-1 cells by up-regulating the expression of histone deacetylase 2].

OBJECTIVE: To investigate the effect of erythromycin (EM) on corticosteroid insensitivity of human THP-1 cells induced by cigarette smoke extract (CSE) and its mechanism. METHODS: THP-1 cells were treated with EM followed by CSE stimulation. Histone deacetylase-2 (HDAC2) short interference RNA (HDAC2-siRNA) was transfected into the cells using Lipofectamine(TM); 2000. Interleukin-8 (IL-8) level in supernatants was measured by ELISA and HDAC2 expression was determined by real-time quantitative PCR (qRT-PCR) and Western blotting. RESULTS: The inhibition ratio of IL-8 in the EM group was significantly higher than that in the CSE group, but lower than that in the control group (P<0.05). The half-maximal inhibitory concentration of dexamethasone (IC50;-Dex) in the EM group was lower than that in the CSE group, but higher than that in the control group (P<0.05). The expression of HDAC2 protein in the EM group was higher than that in the CSE group, but lower than that in the control group (P<0.05). Besides, HDAC2 mRNA and HDAC2 protein expressions were lower in the HDAC2-siRNA group than in the scrambled oligonucleotide (SC) group. EM could reverse HDAC2 mRNA and HDAC2 protein reduction induced by HDAC2-siRNA (P<0.05). CONCLUSION: Corticosteroid sensitivity of THP-1 cells could be reduced by CSE. EM could reverse the corticosteroid insensitivity by up-regulating the expression of HDAC2 protein.

Penicillium marneffei infection within an osteolytic lesion in an HIV-negative patient.

Penicillium marneffei is a thermally dimorphic pathogenic fungus that causes systemic infection similar to disseminated cryptococcosis. P. marneffei is endemic in Southeast Asia, usually infecting HIV-infected individuals; infection of HIV-negative individuals is extremely rare. Here, we describe a disseminated P. marneffei infection within an osteolytic lesion in an HIV-negative patient. A 40-year-old Chinese woman presented with intermittent fever, generalized lymphadenopathy, and a skin rash. Following a sternum biopsy, the patient was diagnosed with P. marneffei infection. An emission computed tomography bone scan revealed the presence of increased radioactivity in the left clavicle and sternum, indicative of an osteolytic lesion. In addition to reporting this very rare case, we also present a brief review of the literature, highlighting the differences in clinical manifestations between HIV-positive and HIV-negative patients infected with P. marneffei as it applies to our case.