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1.
Entropy (Basel) ; 23(5)2021 Apr 23.
Article in English | MEDLINE | ID: covidwho-1202198

ABSTRACT

Complex modeling has received significant attention in recent years and is increasingly used to explain statistical phenomena with increasing and decreasing fluctuations, such as the similarity or difference of spike protein charge patterns of coronaviruses. Different from the existing covariance or correlation coefficient methods in traditional integer dimension construction, this study proposes a simplified novel fractional dimension derivation with the exact Excel tool algorithm. It involves the fractional center moment extension to covariance, which results in a complex covariance coefficient that is better than the Pearson correlation coefficient, in the sense that the nonlinearity relationship can be further depicted. The spike protein sequences of coronaviruses were obtained from the GenBank and GISAID databases, including the coronaviruses from pangolin, bat, canine, swine (three variants), feline, tiger, SARS-CoV-1, MERS, and SARS-CoV-2 (including the strains from Wuhan, Beijing, New York, German, and the UK variant B.1.1.7) which were used as the representative examples in this study. By examining the values above and below the average/mean based on the positive and negative charge patterns of the amino acid residues of the spike proteins from coronaviruses, the proposed algorithm provides deep insights into the nonlinear evolving trends of spike proteins for understanding the viral evolution and identifying the protein characteristics associated with viral fatality. The calculation results demonstrate that the complex covariance coefficient analyzed by this algorithm is capable of distinguishing the subtle nonlinear differences in the spike protein charge patterns with reference to Wuhan strain SARS-CoV-2, which the Pearson correlation coefficient may overlook. Our analysis reveals the unique convergent (positive correlative) to divergent (negative correlative) domain center positions of each virus. The convergent or conserved region may be critical to the viral stability or viability; while the divergent region is highly variable between coronaviruses, suggesting high frequency of mutations in this region. The analyses show that the conserved center region of SARS-CoV-1 spike protein is located at amino acid residues 900, but shifted to the amino acid residues 700 in MERS spike protein, and then to amino acid residues 600 in SARS-COV-2 spike protein, indicating the evolution of the coronaviruses. Interestingly, the conserved center region of the spike protein in SARS-COV-2 variant B.1.1.7 shifted back to amino acid residues 700, suggesting this variant is more virulent than the original SARS-COV-2 strain. Another important characteristic our study reveals is that the distance between the divergent mean and the maximal divergent point in each of the viruses (MERS > SARS-CoV-1 > SARS-CoV-2) is proportional to viral fatality rate. This algorithm may help to understand and analyze the evolving trends and critical characteristics of SARS-COV-2 variants, other coronaviral proteins and viruses.

2.
Crit Care ; 25(1): 50, 2021 02 06.
Article in English | MEDLINE | ID: covidwho-1068599

ABSTRACT

BACKGROUND: Although the immune function of neutrophils in sepsis has been well described, the heterogeneity of neutrophils remains unclear during the process of sepsis. METHODS: In this study, we used a mouse CLP model to simulate the clinical scenario of patients with sepsis, neutrophil infiltration, abnormal distribution and dysfunction was analyzed. LPS was used to stimulate neutrophils in vitro to simulate sepsis; single-cell gene sequencing technology was used to explore the immunological typing. To explore the immunological function of immunosuppressive neutrophils, PD-L1 knockout neutrophils were cocultured with lymphocytes from wild-type mice. RESULTS: We found that neutrophils presented variant dysfunction at the late stage of sepsis, including inhibition of apoptosis, seriously damaged chemotaxis and extensive infiltration into the tissues. Single-cell RNA sequencing revealed that multiple subclusters of neutrophils were differentiated after LPS stimulation. The two-dimensional spatial distribution analysis showed that Foxp3+ T cells were much closer to Ly-6G than the CD4+ and CD8+ cells, indicating that infiltrated neutrophils may play immunomodulatory effect on surrounding T-regs. Further observations showed that LPS mediates PD-L1 over expression through p38α-MSK1/-MK2 pathway in neutrophils. The subsets of highly expressed PD-L1 exert immunosuppressive effect under direct contact mode, including inhibition of T cell activation and induction of T cell apoptosis and trans-differentiation. CONCLUSIONS: Taken together, our data identify a previously unknown immunosuppressive subset of neutrophils as inhibitory neutrophil in order to more accurately describe the phenotype and characteristics of these cells in sepsis.


Subject(s)
Genetic Heterogeneity , Neutrophils/classification , Sepsis/blood , Animals , Disease Models, Animal , Leukocyte Count/methods , Leukocyte Count/statistics & numerical data , Mice , Mice, Inbred C57BL , Neutrophils/physiology , Polymerase Chain Reaction/methods , Sepsis/genetics
3.
Eur J Med Chem ; 205: 112687, 2020 Nov 01.
Article in English | MEDLINE | ID: covidwho-679980

ABSTRACT

The novel coronavirus, 2019-nCoV, has quickly spread across the world and pose serious threat to public health because it can infect people very easily. The major clinical symptoms of 2019-nCoV infection include fever, dry cough, myalgia, fatigue, and diarrhea. The 2019-nCoV belongs to the betacoronavirus family, and gene sequencing results demonstrate that it is a single-stranded RNA virus, closely related to Severe Acute Respiratory Syndrome CoV (SARS-CoV) and Middle East Respiratory Syndrome CoV (MERS-CoV). It has been observed that the virus invades human body mainly through binding to angiotensin-converting enzyme 2 (ACE2) receptors similar to SARS-CoV and the main protease (Mpro) acts as a critical protease for digesting the polyprotein into functional polypeptides during the replication and transcription process of 2019-nCoV. In this review, we summarized the real-time information of 2019-nCoV treatment methods and mainly focused on the chemical drugs including lopinavir/ritonavir, chloroquine, hydroxychloroquine, arbidol, remdesivir, favipiravir and other potential innovative active molecules. Their potential targets, activity, clinical status and side effects are described. In addition, Traditional Chinese Medicine (TCM), Convalescent plasma therapy (CPT) and biological reagents available, as well as the promising vaccine candidates against 2019-nCoV are also discussed.


Subject(s)
Antiviral Agents/therapeutic use , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , COVID-19 , Coronavirus Infections/therapy , Humans , Immunization, Passive , Immunotherapy/methods , Medicine, Chinese Traditional , Pandemics
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