Coexpression of Inhibitory Receptors Enriches for Activated and Functional CD8 T Cells in Murine Syngeneic Tumor Models.

Exhausted T cells have been described in cancer patients and murine tumor models largely based on their expression of various inhibitory receptors. Understanding of the functional attributes of these cells is limited. Here, we report that among CD8 T cells in commonly used syngeneic tumor models, the coexpression of inhibitory receptors PD-1, LAG3, and TIM3 defined a group of highly activated and functional effector cells.

Anti-PD-L1 Treatment Results in Functional Remodeling of the Macrophage Compartment.

Checkpoint inhibitors like anti-PD1/PD-L1 have demonstrated significant therapeutic efficacy in a subset of patients partly through reinvigoration of CD8 T cells. However, their impact on myeloid cells remains largely unknown. Here, we report that anti-PD-L1 treatment favorably impacts the phenotype and function of tumor macrophages by polarizing the macrophage compartment toward a more proinflammatory phenotype.

TGFβ attenuates tumour response to PD-L1 blockade by contributing to exclusion of T cells.

Therapeutic antibodies that block the programmed death-1 (PD-1)-programmed death-ligand 1 (PD-L1) pathway can induce robust and durable responses in patients with various cancers, including metastatic urothelial cancer. However, these responses only occur in a subset of patients. Elucidating the determinants of response and resistance is key to improving outcomes and developing new treatment strategies.

MAP Kinase Inhibition Promotes T Cell and Anti-tumor Activity in Combination with PD-L1 Checkpoint Blockade.

Targeted inhibition of mitogen-activated protein kinase (MAPK) kinase (MEK) can induce regression of tumors bearing activating mutations in the Ras pathway but rarely leads to tumor eradication. Although combining MEK inhibition with T-cell-directed immunotherapy might lead to more durable efficacy, T cell responses are themselves at least partially dependent on MEK activity. We show here that MEK inhibition did profoundly block naive CD8(+) T cell priming in tumor-bearing mice, but actually increased the number of effector-phenotype antigen-specific CD8(+) T cells within the tumor.

The immunoreceptor TIGIT regulates antitumor and antiviral CD8(+) T cell effector function.

Tumors constitute highly suppressive microenvironments in which infiltrating T cells are "exhausted" by inhibitory receptors such as PD-1. Here we identify TIGIT as a coinhibitory receptor that critically limits antitumor and other CD8(+) T cell-dependent chronic immune responses. TIGIT is highly expressed on human and murine tumor-infiltrating T cells, and, in models of both cancer and chronic viral infection, antibody coblockade of TIGIT and PD-L1 synergistically and specifically enhanced CD8(+) T cell effector function, resulting in significant tumor and viral clearance, respectively.

Oral tetrahydrobiopterin improves the beneficial effect of adenoviral-mediated eNOS gene transfer after induction of hindlimb ischemia.

We tested the hypothesis that oral supplementation with the endothelial nitric oxide synthase (eNOS) cofactor tetrahydrobiopterin (BH(4)) improved the therapeutic efficacy of eNOS gene transfer in the ischemic rat hindlimb. BH(4) or vehicle were begun 1 week before induction of hindlimb ischemia, whereas recombinant adenovirus containing bovine eNOS cDNA (AdeNOS) or vehicle [phosphate-buffered saline (PBS)] was infused intra-arterially into the ischemic hindlimb 10 days after induction of ischemia. Rats receiving co-treatment with dietary BH(4) and eNOS gene transfer (the [eNOS, +BH(4)] group) had greater eNOS expression, phospho-eNOS expression (Ser(1177)), Ca(2+)-dependent NOS activity, and nitrite + nitrate concentrations in the ischemic gastrocnemius than did rats receiving AdeNOS alone.

Oxidized low-density lipoprotein induces apoptosis in endothelial progenitor cells by inactivating the phosphoinositide 3-kinase/Akt pathway.

We tested the hypothesis that oxidized low-density lipoprotein (oxLDL)-induced inactivation of Akt within endothelial progenitor cells (EPCs) is mediated at the level of phosphoinositide 3-kinase (PI3K), specifically by nitrosylation of the p85 subunit of PI3K, and that this action is critical in provoking oxLDL-induced EPC apoptosis. Hypercholesterolemic ApoE null mice had a significant reduction of the phosphorylated Akt (p-Akt)/Akt ratio in EPCs, as well as a greater percentage of apoptosis in these cells than EPCs isolated from wild-type (WT) C57Bl/6 mice. EPCs were isolated from WT spleen and exposed to oxLDL in vitro.

Endothelial nitric oxide synthase affects both early and late collateral arterial adaptation and blood flow recovery after induction of hind limb ischemia in mice.

Objective: The goals of this study were to determine if endothelial nitric oxide synthase (eNOS) affects both early and late collateral arterial adaptation and blood flow recovery after severe limb ischemia in a mouse model and to determine if eNOS-derived NO is necessary for recruitment of chemokine (C-X-C motif) receptor 4 (CXCR4)(+) vascular endothelial growth factor receptor-1 (VEGFR1)(+) hemangiocytes to the site of ischemia.

Methods: Two studies were completed. In the first, hind limb ischemia was induced by unilateral femoral artery excision in three groups: C57Bl6 (wild-type), eNOS(-/-), and C57Bl/6 mice treated with N(G)-nitro-L-arginine methyl ester (L-NAME) from 1 day before excision through day 3 after excision (early L-NAME group).

Cellular and molecular mechanism regulating blood flow recovery in acute versus gradual femoral artery occlusion are distinct in the mouse.

Background: Most current animal models of hindlimb ischemia use acute arterial occlusion that does not accurately reflect the pathogenesis of gradual arterial occlusion in humans. We, therefore, developed the first mouse model of gradual arterial occlusion and tested the hypothesis that the mechanisms regulating blood flow recovery are critically dependent on the rate of arterial occlusion.

Methods: Gradual arterial occlusion was induced by placing ameroid constrictors on the proximal and distal left femoral artery, and ligating the femoral arterial branches (n = 36).

The pattern of MyoD and contractile protein localization in primary epaxial myotome reflects the dynamic progression of nascent myoblast differentiation.

The localization of contractile and regulatory proteins in early stages of epaxial primary myotome development was analyzed by immunofluorescence microscopy. Contractile proteins that appear in an ordered sequence in the rostro-caudal axis of somite development were found to reiterate that sequence in the dorso-medial-to-ventro-lateral axis of primary epaxial myotome development. Pair-wise localization of MyoD-titin, desmin-titin, and desmin-myosin defined three zones extending from the dermomyotome dorso-medial lip (DML) into the primary myotome layer.