Intrinsic ADRB2 inhibition improves CAR-T cell therapy efficacy against prostate cancer.

Chimeric antigen receptor (CAR)-T cell therapy has shown limited success in patients with solid tumors. Recent in vitro and in vivo data have shown that adrenoceptor beta-2 (ADRB2) is a novel checkpoint receptor that inhibits T cell-mediated anti-tumor responses. To inhibit ADRB2-mediated inhibitory signaling, we downregulated ADRB2 in CAR-T (shß2-CAR-T) cells via RNA interference, assessed different parameters, and compared them with conventional second-generation CAR-T cells. ADRB2 knockdown CAR-T cells exhibited enhanced cytotoxicity against prostate cancer cell lines in vitro, by increasing CD69, CD107a, GzmB, IFN-γ, T-bet, and GLUT-1. Additionally, ADRB2 deficiency led to improved proliferation, increased CD8/CD4 T cell ratio, and decreased apoptosis in CAR-T cells. shß2-CAR-T cells expressed more Bcl-2 and led to the generation of more significant proportions of T central memory cells. Finally, the ZAP-70/NF-κB signaling axis was shown to be responsible for the improved functions of novel CAR-T cells. In tumor-bearing mice, shß2-CAR-T cells performed better than conventional CAR-T cells in eradicating prostate tumors. The study provides the basis for future clinical and translational CAR-T cell research to focus on adrenergic stress-mediated challenges in the tumor microenvironment of stressed tumors.

Purinergic Receptor P2Y6 Is a Negative Regulator of NK Cell Maturation and Function.

NK cells are critical innate immune cells that target the tumor cells and cancer-initiating cells and clear viruses by producing cytokines and cytotoxic granules. However, the role of the purinergic receptor P2Y6 in the NK cells remains largely unknown. In this study, we discovered that the expression of P2Y6 was decreased upon the activation of the NK cells. Moreover, in the P2Y6-deficient mice, we found that the deficiency of P2Y6 promoted the development of the NK precursor cells into immature NK and mature NK cells. We also found that the P2Y6 deficiency increased, but the P2Y6 receptor agonist UDP or UDP analog 5-OMe-UDP decreased the production of IFN-γ in the activated NK cells. Furthermore, we demonstrated that the P2Y6-deficient NK cells exhibited stronger cytotoxicity in vitro and antimetastatic effects in vivo. Mechanistically, P2Y6 deletion promoted the expression of T-bet (encoded by Tbx21), with or without the stimulation of IL-15. In the absence of P2Y6, the levels of phospho-serine/threonine kinase and pS6 in the NK cells were significantly increased upon the stimulation of IL-15. Collectively, we demonstrated that the P2Y6 receptor acted as a negative regulator of the NK cell function and inhibited the maturation and antitumor activities of the NK cells. Therefore, inhibition of the P2Y6 receptor increases the antitumor activities of the NK cells, which may aid in the design of innovative strategies to improve NK cell-based cancer therapy.

ß2-Adrenergic Receptor Mediated Inhibition of T Cell Function and Its Implications for CAR-T Cell Therapy.

The microenvironment of most tumors is complex, comprising numerous aspects of immunosuppression. Several studies have indicated that the adrenergic system is vital for controlling immunological responses. In the context of the tumor microenvironment, nor-adrenaline (NA) is poured in by innervating nerves and tumor tissues itself. The receptors for nor-adrenaline are present on the surfaces of cancer and immune cells and are often involved in the activation of pro-tumoral signaling pathways. Beta2-adrenergic receptors (ß2-ARs) are an emerging class of receptors that are capable of modulating the functioning of immune cells. ß2-AR is reported to activate regulatory immune cells and inhibit effector immune cells. Blocking ß2-AR increases activation, proliferation, and cytokine release of T lymphocytes. Moreover, ß2-AR deficiency during metabolic reprogramming of T cells increases mitochondrial membrane potential and biogenesis. In the view of the available research data, the immunosuppressive role of ß2-AR in T cells presents it as a targetable checkpoint in CAR-T cell therapies. In this review, we have abridged the contemporary knowledge about adrenergic-stress-mediated ß2-AR activation on T lymphocytes inside tumor milieu.

P2Y6 Deficiency Enhances Dendritic Cell-Mediated Th1/Th17 Differentiation and Aggravates Experimental Autoimmune Encephalomyelitis.

Dendritic cells (DCs) are essential APCs and play a crucial role in initiating and regulating the adaptive immune response. In this study, we have reported that P2Y6, a member of G protein-coupled receptors, inhibits the maturation and activation of DCs via suppressing the activation of the transcription factor NF-κB. Furthermore, loss of P2Y6 does not impact T cells homeostasis in the steady-state. However, in vitro studies show that P2Y6 signaling inhibits the production of IL-12 and IL-23 and the polarization of Th1 and Th17 subsets mediated by DCs. In addition, we find that mice lacking P2Y6 develop more severe experimental autoimmune encephalomyelitis compared with wild-type mice. Our results indicate that P2Y6 functions as a pivotal regulator on DC maturation, and the loss of P2Y6 results in the aggravated experimental autoimmune encephalomyelitis, which suggests that P2Y6 may play a pivotal role in the pathogenesis of autoimmune diseases.

Obeticholic Acid Derivative, T-2054 Suppresses Osteoarthritis via Inhibiting NF-κB-Signaling Pathway.

Osteoarthritis (OA), a degenerative joint disorder, has been reported as the most common cause of disability worldwide. The production of inflammatory cytokines is the main factor in OA. Previous studies have been reported that obeticholic acid (OCA) and OCA derivatives inhibited the release of proinflammatory cytokines in acute liver failure, but they have not been studied in the progression of OA. In our study, we screened our small synthetic library of OCA derivatives and found T-2054 had anti-inflammatory properties. Meanwhile, the proliferation of RAW 264.7 cells and ATDC5 cells were not affected by T-2054. T-2054 treatment significantly relieved the release of NO, as well as mRNA and protein expression levels of inflammatory cytokines (IL-6, IL-8 and TNF-α) in LPS-induced RAW 264.7 cells. Moreover, T-2054 promoted extracellular matrix (ECM) synthesis in TNF-α-treated ATDC5 chondrocytes. Moreover, T-2054 could relieve the infiltration of inflammatory cells and degeneration of the cartilage matrix and decrease the levels of serum IL-6, IL-8 and TNF-α in DMM-induced C57BL/6 mice models. At the same time, T-2054 showed no obvious toxicity to mice. Mechanistically, T-2054 decreased the extent of p-p65 expression in LPS-induced RAW 264.7 cells and TNF-α-treated ATDC5 chondrocytes. In summary, we showed for the first time that T-2054 effectively reduced the release of inflammatory mediators, as well as promoted extracellular matrix (ECM) synthesis via the NF-κB-signaling pathway. Our findings support the potential use of T-2054 as an effective therapeutic agent for the treatment of OA.

Anti-inflammatory activity of extensively hydrolyzed casein is mediated by granzyme B.

OBJECTIVE: Nutritional factors such as extensively hydrolyzed casein (eHC) have been proposed to exert anti-inflammatory activity and affect clinical outcomes such as tolerance development in cow's milk allergy. Granzyme B (GrB) induces apoptosis in target cells and also controls the inflammatory response. Whether eHC could affect the activity of granzyme B and play a role in GrB-mediated inflammatory responses in vitro was unknown. METHODS: The activity of GrB was measured using the substrate Ac-IEPD-pNA. Inflammatory responses were induced with GrB in HCT-8 and THP-1 cells, and pro-inflammatory cytokines were determined at the transcriptional and protein level. RESULTS: GrB could induce the expression of IL-1ß in HCT-8 cells, and IL-8 and MCP-1 in THP-1 cells, respectively. Interestingly, GrB acted synergistically on LPS-induced inflammation in HCT-8 cells and eHC reduced pro-inflammatory responses in both GrB and LPS-mediated inflammation. Further analyses revealed that eHC could inhibit the biological activities and cytotoxic activities of GrB and then could reduce GrB-mediated inflammatory response. CONCLUSION: The results from the current study suggest that anti-inflammatory activity of extensively hydrolyzed casein is, to a certain extent, mediated through modulation of granzyme B activity and responses.

Knockout of P2Y12 aggravates experimental autoimmune encephalomyelitis in mice via increasing of IL-23 production and Th17 cell differentiation by dendritic cells.

Experimental autoimmune encephalomyelitis (EAE), a common model of multiple sclerosis (MS), is mainly mediated by CD4+ T cells with demyelination and neurodegeneration of central nervous system (CNS). The loss of P2Y12 receptor might be associated with the pathogenesis of MS/EAE, but its potential mechanism is still not clear. In this study, more severe EAE developed in P2Y12-knockout (P2Y12-KO) mice compared to WT mice. Knockout of P2Y12 increased expression of IL-17A in the sera and proportion of Th17 cells in spleen and CNS. However, in vitro studies showed that P2Y12 did not influence cell differentiation and proliferation of CD4+ T cells. In bone marrow-derived dendritic cells (BMDCs), loss of P2Y12 significantly increased the production of IL-23 in contrast to the wild-type (WT) BMDCs. FACS analysis indicated that the culture supernatant from P2Y12-deficient DCs promoted more naïve CD4+ T cells to differentiate into Th17 cells. Our finding demonstrated that genetic deletion of P2Y12 receptor broke the balance of Th subtypes by affecting the cytokine profile of BMDCs and resulted in the aggravated EAE, which suggested that P2Y12 may be a potential target in treating MS.

Toll-like receptor-triggered calcium mobilization protects mice against bacterial infection through extracellular ATP release.

Extracellular ATP (eATP), released as a "danger signal" by injured or stressed cells, plays an important role in the regulation of immune responses, but the relationship between ATP release and innate immune responses is still uncertain. In this study, we demonstrated that ATP was released through Toll-like receptor (TLR)-associated signaling in both Escherichia coli-infected mice and lipopolysaccharide (LPS)- or Pam3CSK4-treated macrophages. This ATP release could be blocked completely only by N-ethylmaleimide (NEM), not by carbenoxolone (CBX), flufenamic acid (FFA), or probenecid, suggesting the key role of exocytosis in this process. Furthermore, LPS-induced ATP release could also be reduced dramatically through suppressing calcium mobilization by use of U73122, caffeine, and thapsigargin (TG). In addition, the secretion of interleukin-1ß (IL-1ß) and CCL-2 was enhanced significantly by ATP, in a time- and dose-dependent manner. Meanwhile, macrophage-mediated phagocytosis of bacteria was also promoted significantly by ATP stimulation. Furthermore, extracellular ATP reduced the number of invading bacteria and protected mice from peritonitis by activating purinergic receptors. Mechanistically, phosphorylation of AKT and ERK was overtly increased by ATP in antibacterial immune responses. Accordingly, if we blocked the P2X- and P2Y-associated signaling pathway by using suramin and pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid), tetrasodium salt (PPADS), the ATP-enhanced immune response was restrained significantly. Taken together, our findings reveal an internal relationship between danger signals and TLR signaling in innate immune responses, which suggests a potential therapeutic significance of calcium mobilization-mediated ATP release in infectious diseases.

Co-delivery of LIGHT expression plasmid enhances humoral and cellular immune responses to HIV-1 Nef in mice.

The immunogenicity and efficacy of a DNA vaccine can be greatly enhanced when a gene adjuvant is used. LIGHT, a member of TNF superfamily, can function as a costimulatory molecule for human naïve T cells to proliferate and can be a potential gene adjuvant. In the current study, the eukaryotic expression plasmid pcDNA-nef was constructed by inserting a full-length nef gene into pcDNA3.1(+), and an in vitro transfection experiment suggested that the nef gene could be expressed successfully in mammalian cells. BALB/c mice were immunized with HIV-1 nef DNA vaccine plasmids alone or in combination with LIGHT expression plasmids, and the specific humoral and cellular immune responses were measured. The data showed that HIV-1 nef DNA vaccine plasmids could induce anti-Nef antibodies, Nef-specific lymphocyte proliferation and CTL activity, whereas stronger specific immune responses were induced in mice when co-immunizing with HIV-1 nef DNA vaccine plasmids and LIGHT expression plasmids, suggesting that the eukaryotic expression vector encoding HIV-1 nef is capable of inducing specific immune responses towards HIV-1 Nef and that LIGHT could be considered as a gene adjuvant for HIV-1 DNA vaccination.

shRNA-mediated gene silencing of HDAC11 empowers CAR-T cells against prostate cancer.

Epigenetic mechanisms are involved in several cellular functions, and their role in the immune system is of prime importance. Histone deacetylases (HDACs) are an important set of enzymes that regulate and catalyze the deacetylation process. HDACs have been proven beneficial targets for improving the efficacy of immunotherapies. HDAC11 is an enzyme involved in the negative regulation of T cell functions. Here, we investigated the potential of HDAC11 downregulation using RNA interference in CAR-T cells to improve immunotherapeutic outcomes against prostate cancer. We designed and tested four distinct short hairpin RNA (shRNA) sequences targeting HDAC11 to identify the most effective one for subsequent analyses. HDAC11-deficient CAR-T cells (shD-NKG2D-CAR-T) displayed better cytotoxicity than wild-type CAR-T cells against prostate cancer cell lines. This effect was attributed to enhanced activation, degranulation, and cytokine release ability of shD-NKG2D-CAR-T when co-cultured with prostate cancer cell lines. Our findings reveal that HDAC11 interference significantly enhances CAR-T cell proliferation, diminishes exhaustion markers PD-1 and TIM3, and promotes the formation of T central memory TCM populations. Further exploration into the underlying molecular mechanisms reveals increased expression of transcription factor Eomes, providing insight into the regulation of CAR-T cell differentiation. Finally, the shD-NKG2D-CAR-T cells provided efficient tumor control leading to improved survival of tumor-bearing mice in vivo as compared to their wild-type counterparts. The current study highlights the potential of HDAC11 downregulation in improving CAR-T cell therapy. The study will pave the way for further investigations focused on understanding and exploiting epigenetic mechanisms for immunotherapeutic outcomes.

Modulating Cholesterol Metabolism via ACAT1 Knockdown Enhances Anti-B-Cell Lymphoma Activities of CD19-Specific Chimeric Antigen Receptor T Cells by Improving the Cell Activation and Proliferation.

CD19-specific CAR-T immunotherapy has been extensively studied for the treatment of B-cell lymphoma. Recently, cholesterol metabolism has emerged as a modulator of T lymphocyte function and can be exploited in immunotherapy to increase the efficacy of CAR-based systems. Acetyl-CoA acetyltransferase 1 (ACAT1) is the major cholesterol esterification enzyme. ACAT1 inhibitors previously shown to modulate cardiovascular diseases are now being implicated in immunotherapy. In the present study, we achieved knockdown of ACAT1 in T cells via RNA interference technology by inserting ACAT1-shRNA into anti-CD19-CAR-T cells. Knockdown of ACAT1 led to an increased cytotoxic capacity of the anti-CD19-CAR-T cells. In addition, more CD69, IFN-γ, and GzmB were expressed in the anti-CD19-CAR-T cells. Cell proliferation was also enhanced in both antigen-independent and antigen-dependent manners. Degranulation was also improved as evidenced by an increased level of CD107a. Moreover, the knockdown of ACAT1 led to better anti-tumor efficacy of anti-CD19 CAR-T cells in the B-cell lymphoma mice model. Our study demonstrates novel CAR-T cells containing ACAT1 shRNA with improved efficacy compared to conventional anti-CD19-CAR-T cells in vitro and in vivo.

Exogenous IL-2 delays memory precursors generation and is essential for enhancing memory cells effector functions.

To investigate the impact of paracrine IL-2 signals on memory precursor (MP) cell differentiation, we activated CD8 T cell in vitro in the presence or absence of exogenous IL-2 (ex-IL-2). We assessed memory differentiation by transferring these cells into virus-infected mice. Both conditions generated CD8 T cells that participate in the ongoing response and gave rise to similar memory cells. Nevertheless, when transferred into a naive host, T cells activated with ex-IL-2 generated a higher frequency of memory cells displaying increased functional memory traits. Single-cell RNA-seq analysis indicated that without ex-IL-2, cells rapidly acquire an MP signature, while in its presence they adopted an effector signature. This was confirmed at the protein level and in a functional assay. Overall, ex-IL-2 delays the transition into MP cells, allowing the acquisition of effector functions that become imprinted in their progeny. These findings may help to optimize the generation of therapeutic T cells.

GPR97 depletion aggravates imiquimod-induced psoriasis pathogenesis via amplifying IL-23/IL-17 axis signal pathway.

Skin psoriasis is defined as receiving external stimulation to activate skin dendritic cells (DCs) which can release interleukin 23 (IL-23) to interlink the innate and adaptive immunity as well as induce T helper 17 (Th17) cell differentiation leading to elevated production of interleukin 17 (IL-17) for keratinocytes over production. This autoimmune loop in psoriasis pathogenesis is influenced by G protein-coupled receptor (GPCR) signalling transduction, and in particular, function of adhesion molecule GPR97 in psoriasis endures to be utterly addressed. In this research, our team allocated GPR97 depletion (GPR97-/-), GPR97 conditional depletion on dendritic cell (DC-cKO), and keratin 14-conditional knockout (K14-cKO) mice models to explore the function of GPR97 which influences keratinocytes and skin immunity. It was found that significantly aggravated psoriasis-like lesion in GPR97-/- mice. In addition, hyperproliferative keratinocytes as well as accumulation of DCs and Th17 cells were detected in imiquimod (IMQ)-induced GPR97-/- mice, which was consistent with the results in DC-cKO and K14-cKO psoriasis model. Additional investigations indicated that beclomethasone dipropionate (BDP), an agonist of GPR97, attenuated the psoriasis-like skin disease and restricted HaCaT cells abnormal proliferation as well as Th17 cells differentiation. Particularly, we found that level of NF-κB p65 was increased in GPR97-/- DCs and BDP could inhibit p65 activation in DCs. Role of GPR97 is indispensable and this adhesion receptor may affect immune cell enrichment and function in skin and alter keratinocytes proliferation as well as differentiation in psoriasis.

Unexpected role for granzyme K in CD56bright NK cell-mediated immunoregulation of multiple sclerosis.

Functional NK cell deficiencies are associated with autoimmune diseases, including multiple sclerosis. NK cells can promote or inhibit adaptive immunity via either cytokine production or cytotoxicity toward immature dendritic cells and activated T cells. In humans, this immunoregulatory role resides in the CD56(bright) NK cell subset, which is selectively expanded by daclizumab, a CD25-blocking Ab that suppresses multiple sclerosis-associated inflammation. The objective of this study was to investigate the molecular mechanisms underlying the cytotoxicity of NK cells toward activated T cells. We demonstrated that NK cells induce caspase-independent apoptosis that requires NK cell degranulation and causes mitochondrial dysfunction in activated T cells. Although both granzyme A and granzyme K (GrK) can mediate this form of apoptosis, quantitatively we observed preferential transfer of GrK to target cells. Consequently, gene silencing of GrK in the NK-92 cell line, which retains functional characteristics of CD56(bright) NK cells, profoundly inhibited the ability of NK-92 cells to kill activated syngeneic T cells. Finally, we demonstrated that daclizumab treatment significantly enhanced this newly defined mechanism of cytotoxicity by CD56(bright) NK cells. Our study describes the important physiological role that GrK plays in immunoregulation of adaptive immunity in humans and indicates that therapeutic exploitation of this pathway is beneficial in controlling autoimmunity.

In Situ Synchrotron XRD Characterization of Piezoelectric Al1-xScxN Thin Films for MEMS Applications.

Aluminum scandium nitride (Al1-xScxN) film has drawn considerable attention owing to its enhanced piezoelectric response for micro-electromechanical system (MEMS) applications. Understanding the fundamentals of piezoelectricity would require a precise characterization of the piezoelectric coefficient, which is also crucial for MEMS device design. In this study, we proposed an in situ method based on a synchrotron X-ray diffraction (XRD) system to characterize the longitudinal piezoelectric constant d33 of Al1-xScxN film. The measurement results quantitatively demonstrated the piezoelectric effect of Al1-xScxN films by lattice spacing variation upon applied external voltage. The as-extracted d33 had a reasonable accuracy compared with the conventional high over-tone bulk acoustic resonators (HBAR) devices and Berlincourt methods. It was also found that the substrate clamping effect, leading to underestimation of d33 from in situ synchrotron XRD measurement while overestimation using Berlincourt method, should be thoroughly corrected in the data extraction process. The d33 of AlN and Al0.9Sc0.1N obtained by synchronous XRD method were 4.76 pC/N and 7.79 pC/N, respectively, matching well with traditional HBAR and Berlincourt methods. Our findings prove the in situ synchrotron XRD measurement as an effective method for precise piezoelectric coefficient d33 characterization.

Co-expression of IL-4/IL-15-based inverted cytokine receptor in CAR-T cells overcomes IL-4 signaling in immunosuppressive pancreatic tumor microenvironment.

The efficacy of CAR-T cell therapy has been hindered by several factors that are intrinsic to the tumor microenvironment. Many strategies are being employed to overcome these barriers and improve immunotherapies efficacy. Interleukin (IL)- 4 is a cytokine released by tumor cells inside the tumor microenvironment and it can oppose T cell effector functions via engagement with the IL-4 receptor on the surface of T cells. To overcome IL-4-mediated immunosuppressive signals, we designed a novel inverted cytokine receptor (ICR). Our novel CAR construct (4/15NKG2D-CAR), consisted of an NKG2D-based chimeric antigen receptor, co-expressing IL-4R as an extracellular domain and IL-15R as a transmembrane and intracellular domain. In this way, IL-4R inhibitory signals were converted into IL-15R activation signals downstream. This strategy increased the efficacy of NKG2D-CAR-T cells in the pancreatic tumor microenvironment in vitro and in vivo. 4/15NKG2D-CAR-T cells exhibited increased activation, degranulation, cytokine release, and cytotoxic ability of NKG2D-CAR-T cells against IL-4+ pancreatic cell lines. Furthermore, 4/15NKG2D-CAR-T cells exhibited more expansion, less exhaustion, and an increased percentage of less differentiated T cell phenotypes in vitro when compared with NKG2D-CAR-T cells. That is why IL-4R/IL-15R-modified CAR-T cells eradicated more tumors in vivo and outperformed NKG2D-CAR-T cells. Thus, we report here a novel NKG2D-CAR-T cells that could overcome IL-4-mediated immunosuppression in solid tumors.

GPR116 receptor regulates the antitumor function of NK cells via Gαq/HIF1α/NF-κB signaling pathway as a potential immune checkpoint.

BACKGROUND: NK cell is one of innate immune cells and can protect the body from cancer-initiating cells. It has been reported that GPR116 receptor is involved in inflammation and tumors. However, the effect of GPR116 receptor on the NK cells remains largely unclear. RESULTS: We discovered that GPR116-/- mice could efficiently eliminate pancreatic cancer through enhancing the proportion and function of NK cells in tumor. Moreover, the expression of GPR116 receptor was decreased upon the activation of the NK cells. Besides, GPR116-/- NK cells showed higher cytotoxicity and antitumor activity in vitro and in vivo by producing more GzmB and IFNγ than wild-type (WT) NK cells. Mechanistically, GPR116 receptor regulated the function of NK cells via Gαq/HIF1α/NF-κB signaling pathway. Furthermore, downregulation of GPR116 receptor promoted the antitumor activity of NKG2D-CAR-NK92 cells against pancreatic cancer both in vitro and in vivo. CONCLUSIONS: Our data indicated that GPR116 receptor had a negatively effect on NK cell function and downregulation of GPR116 receptor in NKG2D-CAR-NK92 cells could enhance the antitumor activity, which provides a new idea to enhance the antitumor efficiency of CAR NK cell therapy.

Isoprenaline and salbutamol inhibit pyroptosis and promote mitochondrial biogenesis in arthritic chondrocytes by downregulating ß-arrestin and GRK2.

Rheumatoid arthritis and osteoarthritis overlap many molecular mechanisms of cartilage destruction. Wear and tear in cartilage is chondrocyte-mediated, where chondrocytes act both as effector and target cells. In current study, role of ß2-AR was studied in chondrocytes both in vitro and in vivo. High grade inflammation in vitro and in vivo disease models led to decline in anti-inflammatory ß2-AR signaling and use of ß2-AR agonist attenuated arthritis symptoms. Detailed analysis in chondrocytes revealed that Isoprenaline (ISO) and Salbutamol (SBT) increased cell viability and relative Bcl-2 expression, meanwhile, decreased proteins levels of TNF-α, IL-6 and IL-8 in arthritic chondrocytes when compared with control, respectively. SBT preserved physiological concentration of antioxidant enzymes (CAT, POD, SOD and GSH) in cartilage homogenates and ISO inhibited IL-1ß-mediated genotoxicity in arthritic chondrocytes. Moreover, ß2-AR agonist increased mitochondrial biogenesis and proteoglycan biosynthesis by upregulating the gene expression of PGC1-α, NRF2 and COL2A1, Acan, respectively. ISO and SBT inhibited extracellular matrix (ECM) degradation by downregulating the gene expression of MMP1, MMP3, MMP9 and ADAMTS5 in vitro and in vivo study. In mechanism, ß2-AR agonists decreased ß-arrestin and GRK2 pathway, and as a result mice receiving SBT did not exhibit severe disease. Hence our data suggest ß2-AR agonist administered at disease onset can inhibit receptor internalization by downregulating the expression of ß-arrestin and GRK2 in chondrocytes.

An overview of viral mutagenesis and the impact on pathogenesis of SARS-CoV-2 variants.

Viruses are submicroscopic, obligate intracellular parasites that carry either DNA or RNA as their genome, protected by a capsid. Viruses are genetic entities that propagate by using the metabolic and biosynthetic machinery of their hosts and many of them cause sickness in the host. The ability of viruses to adapt to different hosts and settings mainly relies on their ability to create de novo variety in a short interval of time. The size and chemical composition of the viral genome have been recognized as important factors affecting the rate of mutations. Coronavirus disease 2019 (Covid-19) is a novel viral disease that has quickly become one of the world's leading causes of mortality, making it one of the most serious public health problems in recent decades. The discovery of new medications to cope with Covid-19 is a difficult and time-consuming procedure, as new mutations represent a serious threat to the efficacy of recently developed vaccines. The current article discusses viral mutations and their impact on the pathogenicity of newly developed variants with a special emphasis on Covid-19. The biology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), its mutations, pathogenesis, and treatment strategies are discussed in detail along with the statistical data.