ABSTRACT
The emerging of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak is associated with high morbidity and mortality rates globally. One of the most prominent characteristics of coronavirus disease-19 (COVID-19) is lymphopenia, which is in contrast to other viral infections. This controversy might be explained by the evaluation of impaired innate and adaptive immune responses, during the SARS-CoV-2 infection. During the innate immune response, poly-ADP-ribose polymerase hyperactivated due to virus entry and extensive DNA damage sequentially, leading to nicotinamide adenine dinucleotide (NAD)+ depletion, adenosine triphosphate depletion, and finally cell death. In contrast to the immune response against viral infections, cytotoxic T lymphocytes decline sharply in SARS-CoV-2 infection which might be due to infiltration and trapping in the lower respiratory tract. In addition, there are more factors proposed to involve in lymphopenia in COVID-19 infection such as the role of CD38, which functions as NADase and intensifies NAD depletion, which in turn affects NAD+-dependent Sirtuin proteins, as the regulators of cell death and viability. Lung tissue sequestration following cytokine storm supposed to be another reason for lymphopenia in COVID-19 patients. Protein 7a, as one of the virus-encoded proteins, induces apoptosis in various organ-derived cell lines. These mechanisms proposed to induce lymphopenia, although there are still more studies needed to clarify the underlying mechanisms for lymphopenia in COVID-19 patients.
ABSTRACT
The role of two-pore channel type 2 (TPC2, encoded by tcpn2)-mediated Ca2+ release was recently characterized in zebrafish during establishment of the early spinal circuitry, one of the key events in the coordination of neuromuscular activity. Here, we extend our study to investigate the in vivo role of TPC2 in the regulation of caudal primary motor neuron (CaP) axon extension. We used a combination of TPC2 knockdown with a translation-blocking morpholino antisense oligonucleotide (MO), TPC2 knockout via the generation of a tpcn2dhkz1a mutant line of zebrafish using CRISPR/Cas9 gene-editing and pharmacological inhibition of TPC2 via incubation with bafilomycin A1 (an H+-ATPase inhibitor) or trans-ned-19 (an NAADP receptor antagonist), and showed that these treatments attenuated CaP Ca2+ signaling and inhibited axon extension. We also characterized the expression of an arc1-like transcript in CaPs grown in primary culture. MO-mediated knockdown of ARC1-like in vivo led to attenuation of the Ca2+ transients in the CaP growth cones and an inhibition of axon extension. Together, our new data suggest a link between ARC1-like, TPC2 and Ca2+ signaling during axon extension in zebrafish.
Subject(s)
Calcium Channels , Zebrafish , Animals , Axons/metabolism , Calcium/metabolism , Motor Neurons/metabolism , Zebrafish/genetics , Zebrafish/metabolismABSTRACT
Objective@#To study the distribution of natural killer (NK) cells and the CD38 positive subpopulations in different tissues in rheumatoid arthritis (RA) patients and the mechanism of CD38 agonist.@*Methods@#The levels of NK cells, CD38 positive subpopulation and NK cell surface chemokine receptors (CXCR3, CCR5), as well as granzyme B and perforin were detected by flow cytometry in peripheral blood and knee synovial fluid. The isolated cells were then cultured in vitro and divided into 3 groups, namely blank control group, IB4 stimulation group (Anti-CD38 mAb), IL-2 and IB4 co-stimulation group. And the concentration of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in culture supernatants was determined by enzyme linked immunosorbent assay (ELISA). Liposome CD38-siRNA was transfected into peripheral blood lymphocytes of RA patients, and transfection efficiency was detected by reverse transcription-polymerase chain reaction (RT-PCR). The effect of CD38 and CD38-siRNA silencing on the expression of phospholipase C-gamma 1 (PLC-γ1) protein in the peripheral blood lymphocytes of RA was detected by Western blot.@*Results@#The expression of CCR5 and CXCR3 in NK cells in peripercal NK cells of RA was significantly higher than that in normal healthy subjects (P<0.05). The two chemokine receptors (CXCR3, CCR5) were mainly expressed in CD38+ NK cell subsets. The levels of granzyme B and perforin in synovial lymphocytes cells were significantly higher than those in peripheral blood lymphocytes (P<0.05). The secretion of IL-6 and TNF-α in synovial and peripheral blood lymphocytes cells existed significant difference only in IL-2 and IB4 co-stimulation group (P<0.05). The levels of PLC-γ1 protein in the peripheral blood lymphocytes of RA patients was significantly decreased than that in the blank control group after the treatment with CD38-siRNA (P<0.05).@*Conclusions@#The synovial NK cells are more lethal than the peripheral NK cells in the RA patients. CD38 might mediate the phosphorylation of intracellular proteins via the Protain kinase C (PKC) pathway. Blocking CD38 molecules can reduce the phosphorylation level of intracellular proteins. CD38 maybe involved in the mechanism of chemotaxis and killing capability of NK cells.
ABSTRACT
Objective To study the distribution of natural killer (NK) cells and the CD38 positive subpopulations in different tissues in rheumatoid arthritis (RA) patients and the mechanism of CD38 agonist.Methods The levels of NK cells,CD38 positive subpopulation and NK cell surface chemokine receptors (CXCR3,CCRS),as well as granzyme B and perforin were detected by flow cytometry in peripheral blood and knee synovial fluid.The isolated cells were then cultured in vitro and divided into 3 groups,namely blank control group,IB4 stimulation group (Anti-CD38 mAb),IL-2 and IB4 co-stimulation group.And the concentration of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in culture supernatants was determined by enzyme linked immunosorbent assay (ELISA).Liposome CD38-siRNA was transfected into peripheral blood lymphocytes of RA patients,and transfection efficiency was detected by reverse transcription-polymerase chain reaction (RT-PCR).The effect of CD38 and CD38-siRNA silencing on the expression of phospholipase C-gamma 1 (PLC-γ1) protein in the peripheral blood lymphocytes of RA was detected by Western blot.Results The expression of CCR5 and CXCR3 in NK cells in peripercal NK cells of RA was significantly higher than that in normal healthy subjects (P ＜ 0.05).The two chemokine receptors (CXCR3,CCRS) were mainly expressed in CD38 + NK cell subsets.The levels of granzyme B and perforin in synovial lymphocytes cells were significantly higher than those in peripheral blood lymphocytes (P ＜0.05).The secretion of IL-6 and TNF-α in synovial and peripheral blood lymphocytes cells existed significant difference only in IL-2 and IB4 co-stimulation group (P ＜0.05).The levels of PLC-γ1 protein in the peripheral blood lymphocytes of RA patients was significantly decreased than that in the blank control group after the treatment with CD38-siRNA (P ＜ 0.05).Conclusions The synovial NK cells are more lethal than the peripheral NK cells in the RA patients.CD38 might mediate the phosphorylation of intracellular proteins via the Protain kinase C (PKC) pathway.Blocking CD38 molecules can reduce the phosphorylation level of intracellular proteins.CD38 maybe involved in the mechanism of chemotaxis and killing capability of NK cells.
