S-Allyl-L-cysteine (SAC) inhibits copper-induced apoptosis and cuproptosis to alleviate cardiomyocyte injury.

Cardiomyocyte injury is closely related to various myocardial diseases, and S-Allyl-L-cysteine (SAC) has been found to have myocardial protective effects, but its mechanism is currently unclear. Meanwhile, copper also has various physiological functions, and this study found that copper inhibited cell viability in a concentration and time-dependent manner, and was associated with multiple modes of death. Elesclomol plus CuCl2 (ES + Cu) significantly inhibited cell viability, and this effect could only be blocked by copper chelator TTM, indicating that "ES + Cu" induced cuproptosis in cardiomyocytes. SAC reduced the inhibitory effects of high concentration copper and "ES + Cu" on cell viability in a concentration and time-dependent manner, indicating that SAC plays a cardioprotective role under stress. Further mechanism study showed that high concentration of copper significantly induced cardiomyocyte apoptosis and increased the levels of LDH, MDA and ROS, while SAC inhibited the apoptosis and injury of cardiomyocytes induced by copper. "ES + Cu" significantly increased intracellular copper levels and decreased the expression of FDX1, LIAS, Lip-DLST and Lip-DLAT; FDX1 siRNA did not affect the expression of LIAS, but further reduced the expression of Lip-DLST and Lip-DLAT; SAC did not affect the expression of these genes, but enhanced the effect of "ES + Cu" in down-regulating these gene expression and restored intracellular copper levels. In addition, "ES + Cu" reduced ATP production, weakened the activity of mitochondrial complex I and III, inhibited cell viability, and increased the contents of injury markers LDH, MDA, CK-MB and cTnI, while SAC significantly improved mitochondrial function injury and cardiomyocyte injury induced by "ES + Cu". Therefore, SAC can inhibit apoptosis and cuproptosis to play a cardioprotective role.

Monocytic myeloid-derived suppressor cells regulate T-cell responses against vaccinia virus.

Vaccinia virus (VV) can potently activate NK- and T-cell responses, leading to efficient viral control and generation of long-lasting protective immunity. However, immune responses against viral infections are often tightly controlled to avoid collateral damage and systemic inflammation. We have previously shown that granulocytic myeloid-derived suppressor cells (g-MDSCs) can suppress the NK-cell response to VV infection. It remains unknown what regulates T-cell responses to VV infection in vivo. In this study, we first showed that monocytic MDSCs (m-MDSCs), but not g-MDSCs, from VV-infected mice could directly suppress CD4+ and CD8+ T-cell activation in vitro. We then demonstrated that defective recruitment of m-MDSCs to the site of VV infection in CCR2-/- mice enhanced VV-specific CD8+ T-cell response and that adoptive transfer of m-MDSCs into VV-infected mice suppressed VV-specific CD8+ T-cell activation, leading to a delay in viral clearance. Mechanistically, we further showed that T-cell suppression by m-MDSCs is mediated by indication of iNOS and production of NO upon VV infection, and that IFN-γ is required for activation of m-MDSCs. Collectively, our results highlight a critical role for m-MDSCs in regulating T-cell responses against VV infection and may suggest potential strategies using m-MDSCs to modulate T-cell responses during viral infections.

NK cell-extrinsic IL-18 signaling is required for efficient NK-cell activation by vaccinia virus.

NK cells are important for the control of vaccinia virus (VV) in vivo. Recent studies have shown that multiple pathways are required for effective activation of NK cells. These include both TLR-dependent and -independent pathways, as well as the NKG2D activating receptor that recognizes host stress-induced NKG2D ligands. However, it remains largely unknown what controls the upregulation of NKG2D ligands in response to VV infection. In this study using C57BL/6 mice, we first showed that IL-18 is critical for NK-cell activation and viral clearance. We then demonstrated that IL-18 signaling on both NK cells and DCs is required for efficient NK-cell activation upon VV infection in vitro. We further showed in vivo that efficient NK-cell activation in response to VV is dependent on DCs and IL-18 signaling in non-NK cells, suggesting an essential role for NK cell-extrinsic IL-18 signaling in NK-cell activation. Mechanistically, IL-18 signaling in DCs promotes expression of Rae-1, an NKG2D ligand. Collectively, our data reveal a previously unrecognized role for NK cell-extrinsic IL-18 signaling in NK-cell activation through upregulation of NKG2D ligands. These observations may provide insights into the design of effective NK-cell-based therapies for viral infections and cancer.

Both NK cell-intrinsic and -extrinsic STAT1 signaling are required for NK cell response against vaccinia virus.

NK cells play an important role in innate immune control of the infection with vaccinia virus (VV). However, it remains incompletely defined how the activation of NK cells in response to VV is regulated. In this study, we showed that STAT1 was critical for NK cell activation upon VV infection and the subsequent clearance of VV infection in vivo. We further demonstrated that STAT1 signaling in both NK and accessory cells such as dendritic cells was required for efficient NK cell activation upon VV infection. Mechanistically, STAT1 signaling in dendritic cells promoted the expression of NKG2D ligands, which is required for NK cell activation via the NKG2D pathway. Taken together, our data suggest that STAT1 mediates anti-VV effect by promoting NK cell activation through both NK-intrinsic and extrinsic mechanisms and may provide insights into the design of effective NK cell-based therapies for viral infections.

Heparan sulfate, an endogenous TLR4 agonist, promotes acute GVHD after allogeneic stem cell transplantation.

Graft-versus-host disease (GVHD) remains the most common cause of nonrelapse-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although T-cell depletion and intensive immunosuppression are effective in the control of GVHD, they are often associated with higher rates of infection and tumor recurrence. In this study, we showed that heparan sulfate (HS), an extracellular matrix component, can activate Toll-like receptor 4 on dendritic cells in vitro, leading to the enhancement of dendritic cell maturation and alloreactive T-cell responses. We further demonstrated in vivo that serum HS levels were acutely elevated at the onset of clinical GVHD in mice after allo-HSCT. Treatment with the serine protease inhibitor α1-antitrypsin decreased serum levels of HS, leading to a reduction in alloreactive T-cell responses and GVHD severity. Conversely, an HS mimetic that increased serum HS levels accelerated GVHD. In addition, in patients undergoing allo-HSCT for hematologic malignancies, serum HS levels were elevated and correlated with the severity of GVHD. These results identify a critical role for HS in promoting acute GVHD after allo-HSCT, and they suggest that modulation of HS release may have therapeutic potential for the control of clinical GVHD.

NK cell response to vaccinia virus is regulated by myeloid-derived suppressor cells.

NK cells are critical for the innate immune control of poxviral infections. Previous studies have shown that NK cells are efficiently activated in response to infection with vaccinia virus (VV), the most studied member of the poxvirus family. However, it remains unknown whether the activation of NK cells in response to VV infection is tightly regulated. In this study, we showed that myeloid-derived suppressor cells (MDSCs) rapidly accumulated at the site of VV infection. In vivo depletion of MDSCs led to enhanced NK cell proliferation, activation, and function in response to VV infection. This was accompanied by an increase in mortality and systemic IFN-γ production. We further demonstrated that the granulocytic-MDSC (G-MDSC) subset was responsible for the suppression on NK cells and that this suppression was mediated by reactive oxygen species. These results indicate that G-MDSCs can negatively regulate NK cell activation and function in response to VV infection and suggest that manipulation of G-MDSCs could represent an attractive strategy for regulating NK cell activities for potential therapeutic benefits.

The development and function of memory regulatory T cells after acute viral infections.

Natural CD4+CD25+Foxp3+ regulatory T cells (Tregs) are critical for the control of immune responses to pathogens. However, most studies have focused on chronic infections, in which pathogen-specific Tregs contribute to pathogen persistence and, in some cases, concomitant immunity. How Tregs behave and function following acute infections remains largely unknown. In this article, we show that pathogen-specific Tregs can be activated and expand upon acute viral infections in vivo. The activated Tregs then contract to form a memory pool after resolution of the infection. These memory Tregs expand rapidly upon a secondary challenge, secrete large amounts of IL-10, and suppress excessive immunopathological conditions elicited by recall expansion of non-Tregs via an IL-10-dependent mechanism. Our work reveals a memory Treg population that develops after acute viral infections and may help in the design of effective strategies to circumvent excessive immunopathological effects.

Stem-like CD8+ T cells in cancer.

Stem-like CD8+ T cells (TSL) are a subset of immune cells with superior persistence and antitumor immunity. They are TCF1+ PD-1+ and important for the expansion of tumor specific CD8+ T cells in response to checkpoint blockade immunotherapy. In acute infections, naïve CD8+ T cells differentiate into effector and memory CD8+ T cells; in cancer and chronic infections, persistent antigen stimulation can lead to T cell exhaustion. Recent studies have highlighted the dichotomy between late dysfunctional (or exhausted) T cells (TLD) that are TCF1- PD-1+ and self-renewing TCF1+ PD-1+ TSL from which they derive. TCF1+ TSL cells are considered to have stem cell-like properties akin to memory T cell populations and can give rise to cytotoxic effector and transitory T cell phenotypes (TTE) which mediate tumor control. In this review, we will discuss recent advances made in research on the formation and expansion of TSL, as well as distinct niches required for their differentiation and maintenance in the setting of cancer. We will also discuss potential strategies to generate these cells, with clinical implications for stemness enhancement in vaccine design, immune checkpoint blockade (ICB), and adoptive T cell therapies.

Postinfusion PD-1+ CD8+ CAR T cells identify patients responsive to CD19 CAR T-cell therapy in non-Hodgkin lymphoma.

ABSTRACT: Chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Robust biomarkers and a complete understanding of CAR T-cell function in the postinfusion phase remain limited. Here, we used a 37-color spectral flow cytometry panel to perform high dimensional single-cell analysis of postinfusion samples in 26 patients treated with CD28 costimulatory domain containing commercial CAR T cells for NHL and focused on computationally gated CD8+ CAR T cells. We found that the presence of postinfusion Programmed cell death protein 1 (PD-1)+ CD8+ CAR T cells at the day 14 time point highly correlated with the ability to achieve complete response (CR) by 6 months. Further analysis identified multiple subtypes of CD8+ PD-1+ CAR T cells, including PD-1+ T cell factor 1 (TCF1)+ stem-like CAR T cells and PD-1+ T-cell immunoglobulin and mucin-domain containing-3 (TIM3)+ effector-like CAR T cells that correlated with improved clinical outcomes such as response and progression-free survival. Additionally, we identified a subset of PD-1+ CD8+ CAR+ T cells with effector-like function that was increased in patients who achieved a CR and was associated with grade 3 or higher immune effector cell-associated neurotoxicity syndrome. Here, we identified robust biomarkers of response to CD28 CAR T cells and highlight the importance of PD-1 positivity in CD8+ CAR T cells after infusion in achieving CR.

Myeloid-derived suppressor cells regulate natural killer cell response to adenovirus-mediated gene transfer.

The attendant innate and adaptive immune responses to viral vectors have posed a significant hurdle for clinical application of viral vector-mediated gene therapy. Previous studies have shown that natural killer (NK) cells play a critical role in innate immune elimination of adenoviral vectors in the liver. However, it is not clear how the NK cell response to adenoviral vectors is regulated. In this study, we identified a role for granulocytic myeloid-derived suppressor cells (G-MDSCs) in this process. We show that in vivo administration of adenoviral vectors results in rapid accumulation of G-MDSCs early during adenoviral infection. In vivo depletion of both MDSC populations, but not monocytic MDSCs (M-MDSCs) alone, resulted in accelerated clearance of adenoviral vectors in the liver. This was accompanied by enhanced NK cell proliferation and activation, suggesting a role for MDSCs, probably G-MDSCs, in suppressing NK cell activation and function in vivo. We further demonstrate in vitro that G-MDSCs, but not M-MDSCs, are responsible for the suppression of NK cell activation. In addition, we show that adenoviral infection activated G-MDSCs to produce higher levels of reactive oxygen species (ROS) and that G-MDSC-mediated suppression of NK cells is mediated by ROS, specifically, H(2)O(2). This study demonstrates for the first time that the NK cell response to adenoviral vectors is negatively regulated by G-MDSCs and suggests that G-MDSC-based strategies could potentially improve the outcome of viral vector-mediated gene therapy.

Intrinsic IL-21 signaling is critical for CD8 T cell survival and memory formation in response to vaccinia viral infection.

CD4 T cell help plays an important role in promoting CD8 T cell immunity to pathogens. In models of infection with vaccinia virus (VV) and Listeria monocytogenes, CD4 T cell help is critical for the survival of activated CD8 T cells during both the primary and memory recall responses. Still unclear, however, is how CD4 T cell help promotes CD8 T cell survival. In this study, we first showed that CD4 T cell help for the CD8 T cell response to VV infection was mediated by IL-21, a cytokine produced predominantly by activated CD4 T cells, and that direct action of IL-21 on CD8 T cells was critical for the VV-specific CD8 T cell response in vivo. We next demonstrated that this intrinsic IL-21 signaling was essential for the survival of activated CD8 T cells and the generation of long-lived memory cells. We further revealed that IL-21 promoted CD8 T cell survival in a mechanism dependent on activation of the STAT1 and STAT3 pathways and subsequent upregulation of the prosurvival molecules Bcl-2 and Bcl-x(L). These results identify a critical role for intrinsic IL-21 signaling in CD8 T cell responses to an acute viral infection in vivo and may help design effective vaccine strategies.

Toll-like receptor 8-mediated activation of murine plasmacytoid dendritic cells by vaccinia viral DNA.

Plasmacytoid dendritic cells (pDCs) play a critical role in antiviral immunity through their ability to produce large amounts of type I IFNs. Activation of pDCs upon viral infection has been shown to be dependent on MyD88 and mediated by Toll-like receptors (TLR) 7 and 9, which sense viral ssRNA and CpG DNA, respectively. In this study, we showed that murine pDC recognition of vaccinia virus (VV), a dsDNA virus, was MyD88-dependent but TLR9-independent. Using HEK293 cells transfected with murine TLR7 or TLR8 and a NF-kappaB luciferase reporter, we demonstrated that stimulation of TLR8-, but not TLR7-, transfected cells with either VV or VV DNA resulted in substantial NF-kappaB activation, and that siRNA-mediated knockdown of TLR8 expression in pDCs led to a complete ablation of VV-induced type I IFN production. We further identified that the VV genome was rich in poly(A)/T sequences, and synthetic poly(A) and poly T oligodeoxynucleotides were capable of activating pDCs in a TLR8-dependent manner. In vivo, TLR8-MyD88-dependent pDC activation played a critical role in innate immune control of VV infection. Collectively, our data are unique in demonstrating that TLR8 is required for sensing poly(A)/T-rich DNA in pDCs, and that murine TLR8 is functional in the context of a viral infection.

Direct TLR2 signaling is critical for NK cell activation and function in response to vaccinia viral infection.

Natural killer (NK) cells play an essential role in innate immune control of poxviral infections in vivo. However, the mechanism(s) underlying NK cell activation and function in response to poxviruses remains poorly understood. In a mouse model of infection with vaccinia virus (VV), the most studied member of the poxvirus family, we identified that the Toll-like receptor (TLR) 2-myeloid differentiating factor 88 (MyD88) pathway was critical for the activation of NK cells and the control of VV infection in vivo. We further showed that TLR2 signaling on NK cells, but not on accessory cells such as dendritic cells (DCs), was necessary for NK cell activation and that this intrinsic TLR2-MyD88 signaling pathway was required for NK cell activation and played a critical role in the control of VV infection in vivo. In addition, we showed that the activating receptor NKG2D was also important for efficient NK activation and function, as well as recognition of VV-infected targets. We further demonstrated that VV could directly activate NK cells via TLR2 in the presence of cytokines in vitro and TLR2-MyD88-dependent activation of NK cells by VV was mediated through the phosphatidylinositol 3-kinase (PI3K)-extracellular signal-regulated kinase (ERK) pathway. Taken together, these results represent the first evidence that intrinsic TLR signaling is critical for NK cell activation and function in the control of a viral infection in vivo, indicate that multiple pathways are required for efficient NK cell activation and function in response to VV infection, and may provide important insights into the design of effective strategies to combat poxviral infections.

NKG2D is required for NK cell activation and function in response to E1-deleted adenovirus.

Despite high transduction efficiency in vivo, the application of recombinant E1-deleted adenoviral vectors for in vivo gene therapy has been limited by the attendant innate and adaptive immune responses to adenoviral vectors. NK cells have been shown to play an important role in innate immune elimination of adenoviral vectors in vivo. However, the mechanisms underlying NK cell activation and function in response to adenoviral vectors remain largely undefined. In this study, we showed that NK cell activation upon adenoviral infection was dependent on accessory cells such as dendritic cells and macrophages and that cell contact-dependent signals from the accessory cells are necessary for NK cell activation. We further demonstrated that ligands of the NK activating receptor NKG2D were upregulated in accessory cells upon adenoviral infection and that blockade of NKG2D inhibited NK cell activation upon adenoviral infection, leading to a delay in adenoviral clearance in vivo. In addition, NKG2D was required for NK cell-mediated cytolysis on adenovirus-infected targets. Taken together, these results suggest that efficient NK cell activation and function in response to adenoviral infection is critically dependent on the NKG2D pathway, which understanding may assist in the design of effective strategies to improve the outcome of adenovirus-mediated gene therapy.

How Does Social Capital Affect Residents' Waste-Separation Behavior? Evidence from China.

The increasing amount of waste produced has been a challenge for human health and the environment, causing a call for effective waste management measures in which household waste separation is of great significance. Although an expanding body of literature has examined the impact of social capital on individual waste-separation behavior, few studies have explicitly discussed the endogeneity problem and the influence mechanisms. Accordingly, our study investigates the effect of social capital on waste-separation behavior and corresponding mechanisms using a national survey dataset of China. The study also reveals the heterogeneity of the influence of individual characteristics on waste-separation behavior. Our results demonstrate that social capital casts a significant positive impact on waste-separation behavior, providing opportunities for individuals' social learning and strengthening the reputation effect. The heterogeneous effects of social capital reveal that women, higher-educated individuals, and political party members present better waste-separation behavior. Besides, the impact of social capital varies between urban and rural areas and among different age groups. Our study provides empirical evidence for policy making of household waste-separation management in developing countries from the perspective of informal institutions.

miR-142-5p Encapsulated by Serum-Derived Extracellular Vesicles Protects against Acute Lung Injury in Septic Rats following Remote Ischemic Preconditioning via the PTEN/PI3K/Akt Axis.

This study intends to investigate the effects of miR-142-5p encapsulated by serum-derived extracellular vesicles (EVs) on septic acute lung injury (ALI) following remote ischemic preconditioning (RIPC) through a PTEN-involved mechanism. ALI was induced in rats by lipopolysaccharide (LPS) injection, 24 h before which RIPC was performed via the left lower limb. Next, the binding affinity between miR-142-5p and PTEN was identified. EVs were isolated from serum and injected into rats. The morphology of lung tissues, pulmonary edema, and inflammatory cell infiltration into lung tissues were then assessed, and TNF-α and IL-6 levels in serum and lung tissues were measured. The results indicated that RIPC could attenuate ALI in sepsis. miR-142-5p expression was increased in serum, lung tissues, and serum-derived EVs of ALI rats following RIPC. miR-142-5p could target PTEN to activate the PI3K/Akt signaling pathway. miR-142-5p shuttled by serum-derived EVs reduced pulmonary edema, neutrophil infiltration, and TNF-α and IL-6 levels, thus alleviating ALI in LPS-induced septic rats upon RIPC. Collectively, serum-derived EVs-loaded miR-142-5p downregulated PTEN and activated PI3K/Akt to inhibit ALI in sepsis following RIPC, thus highlighting potential therapeutic molecular targets against ALI in sepsis.

A critical role for direct TLR2-MyD88 signaling in CD8 T-cell clonal expansion and memory formation following vaccinia viral infection.

Recent advances have suggested a crucial role of the innate immunity in shaping adaptive immune responses. How activation of innate immunity promotes adaptive T-cell responses to pathogens in vivo is not fully understood. It has been thought that Toll-like receptor (TLR)-mediated control of adaptive T-cell responses is mainly achieved by the engagement of TLRs on antigen-presenting cells to promote their maturation and function. In this study, we showed that direct TLR2-myeloid differentiating factor 88 (MyD88) signaling in CD8 T cells was also required for their efficient clonal expansion by promoting the survival of activated T cells on vaccinia viral infection in vivo. Effector CD8 T cells that lacked direct TLR2-MyD88 signaling did not survive the contraction phase to differentiate into long-lived memory cells. Furthermore, we observed that direct TLR2 ligation on CD8 T cells promoted CD8 T-cell proliferation and survival in vitro in a manner dependent on the phosphatidylinositol 3-kinase (PI3K)-Akt pathway activation and that activation of Akt controlled memory cell formation in vivo. These results identify a critical role for intrinsic TLR2-MyD88 signaling and PI3K-Akt pathway activation in CD8 T-cell clonal expansion and memory formation in vivo and could lead to the development of new vaccine approaches.

Induction of type I IFN is required for overcoming tumor-specific T-cell tolerance after stem cell transplantation.

Tumor-specific T-cell tolerance represents one major mechanism of tumor-induced immune evasion. Myeloablative chemotherapy with stem cell transplantation may offer the best chance of achieving a state of minimal residual disease and, thus, minimize tumor-induced immune evasion. However, studies have shown that tumor-specific T-cell tolerance persists after transplantation. Here, we showed that CD4(+)CD25(+) regulatory T (T(Reg)) cells play a critical role in tumor-specific CD8(+) T-cell tolerance after transplantation. Removal of T(Reg) cells from the donor lymphocyte graft did not overcome this tolerance because of rapid conversion of donor CD4(+)CD25(-) T cells into CD4(+)CD25(+)Foxp3(+) T(Reg) cells in recipients after transplantation, and depletion of T(Reg) cells in recipients was necessary for the reversal of tumor-specific tolerance. These results suggest that strategies capable of overcoming T-cell tolerance in recipients are required to promote antitumor immunity after transplantation. Toward this goal, we showed that dendritic cell (DC) vaccines coadministered with the TLR9 ligand, CpG could effectively overcome tumor-specific tolerance, leading to significant prolongation of tumor-free survival after transplantation. We further showed that CpG-induced type I interferon was critical for the reversal of tumor-specific tolerance in vivo. Collectively, these results may suggest effective immunotherapeutic strategies for treating cancer after stem cell transplantation.

γδT Cells Are Required for CD8+ T Cell Response to Vaccinia Viral Infection.

Vaccinia virus (VV) is the most studied member of the poxvirus family, is responsible for the successful elimination of smallpox worldwide, and has been developed as a vaccine vehicle for infectious diseases and cancer immunotherapy. We have previously shown that the unique potency of VV in the activation of CD8+ T cell response is dependent on efficient activation of the innate immune system through Toll-like receptor (TLR)-dependent and -independent pathways. However, it remains incompletely defined what regulate CD8+ T cell response to VV infection. In this study, we showed that γδT cells play an important role in promoting CD8+ T cell response to VV infection. We found that γδT cells can directly present viral antigens in the context of MHC-I for CD8+ T cell activation to VV in vivo, and we further demonstrated that cell-intrinsic MyD88 signaling in γδT cells is required for activation of γδT cells and CD8+ T cells. These results illustrate a critical role for γδT cells in the regulation of adaptive T cell response to viral infection and may shed light on the design of more effective vaccine strategies based on manipulation of γδT cells.

Targeting Tumor-Associated Macrophages in Cancer Immunotherapy.

Tumor-associated macrophages (TAMs) represent the most abundant leukocyte population in most solid tumors and are greatly influenced by the tumor microenvironment. More importantly, these macrophages can promote tumor growth and metastasis through interactions with other cell populations within the tumor milieu and have been associated with poor outcomes in multiple tumors. In this review, we examine how the tumor microenvironment facilitates the polarization of TAMs. Additionally, we evaluate the mechanisms by which TAMs promote tumor angiogenesis, induce tumor invasion and metastasis, enhance chemotherapeutic resistance, and foster immune evasion. Lastly, we focus on therapeutic strategies that target TAMs in the treatments of cancer, including reducing monocyte recruitment, depleting or reprogramming TAMs, and targeting inhibitory molecules to increase TAM-mediated phagocytosis.