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Con A hepatitis is regarded as a T cell–mediated model of acute liver injury. Mincle is a C-type lectin receptor that is critical in the immune response to mycobacteria and fungi but does not have a well-defined role in preclinical models of non-pathogen–mediated inflammation. Because Mincle can ligate the cell death ligand SAP130, we postulated that Mincle signaling drives intrahepatic inflammation and liver injury in Con A hepatitis. Acute liver injury was assessed in the murine Con A hepatitis model using C57BL/6, Mincle−/−, and Dectin-1−/− mice. The role of C/EBPβ and hypoxia-inducible factor-1α (HIF-1α) signaling was assessed using selective inhibitors. We found that Mincle was highly expressed in hepatic innate inflammatory cells and endothelial cells in both mice and humans. Furthermore, sterile Mincle ligands and Mincle signaling intermediates were increased in the murine liver in Con A hepatitis. Most significantly, Mincle deletion or blockade protected against Con A hepatitis, whereas Mincle ligation exacerbated disease. Bone marrow chimeric and adoptive transfer experiments suggested that Mincle signaling in infiltrating myeloid cells dictates disease phenotype. Conversely, signaling via other C-type lectin receptors did not alter disease course. Mechanistically, we found that Mincle blockade decreased the NF-κβ–related signaling intermediates C/EBPβ and HIF-1α, both of which are necessary in macrophage-mediated inflammatory responses. Accordingly, Mincle deletion lowered production of nitrites in Con A hepatitis and inhibition of both C/EBPβ and HIF-1α reduced the severity of liver disease. Our work implicates a novel innate immune driver of Con A hepatitis and, more broadly, suggests a potential role for Mincle in diseases governed by sterile inflammation.

Introduction Efficacy of cellular immunotherapy for liver metastases (LM) has been limited by poor trafficking and elevated intra-tumoral pressures. In a phase 1b study, we found that regional, pressure-enabled drug delivery (PEDD, TriSalus Life Sciences, Inc.) improved LM CAR-T delivery. We hypothesized that PEDD of CAR-T in a murine model can improve LM control. Methods LM bearing CD45.2 mice were treated with CD45.1 anti-CEA CAR-T via systemic delivery (SD, tail vein) or regional delivery (RD, portal vein) at low pressure (LPRD) vs. high pressure (HPRD) to model PEDD. Flow rates were calibrated to achieve LPRD or HPRD. Tumor bioluminescence (TB), flow cytometry (FC), immunofluorescence (IF), & quantitative polymerase chain reaction (qPCR) were assessed on various post-treatment days (PTD). Results FC of liver non-parenchymal cells on PTD7 showed increased CAR-T density in HPRD & LPRD (9.4% & 11.0%, p = 0.03 & 0.002) vs. SD (3.7%). qPCR of the CAR transgene supported this observation, but was not significant (HPRD 135.8, p = 0.76, LPRD 108.6, p = 0.40 vs. SD 69.8). TB was lower in RD vs. SD up to PTD7 (log2 fold-change HPRD −1.3 & LPRD −0.9 vs. SD 4.3, p = 0.005 & 0.006). Tumor proliferation by Ki67 IF was significantly reduced with RD vs. control (HPRD & LPRD, p < 0.001 & p = 0.05) with HPRD superior to LPRD (p = 0.03). Serum liver enzymes were not significantly elevated using HPRD vs. LPRD at PTD7 (AST/ALT 154.7/36.3 vs. 139.1/29.1, p = 0.84/0.67), but did rise at PTD17, correlating with tumor progression (AST/ALT 800.7/229.3 vs. 387.5/139.5, p = 0.10/0.28). Conclusions RD increased LM CAR-T delivery and HPRD showed evidence of improved CAR-T trafficking and tumor control relative to LPRD. Further clinical testing of PEDD is planned for LM cellular therapy.

Introduction We have demonstrated safety and clinical activity with anti-CEA CAR-T (Sorrento/TNK Therapeutics, Inc.) regional infusions for treatment of liver metastases (LM) using a pressure-enabled drug delivery device (PEDD™, TriSalus™ Life Sciences, Inc.) to increase CAR-T penetration. To further explore the potential benefit of PEDD, we developed a pre-clinical murine LM model that enables correlation of infusion pressure with response. Methodology Mice with CEA+ LM were infused with anti-CEA CAR-T into the portal vein with specified rate and pressure levels. Flow cytometry (FC), bioluminescence imaging (BLI), and serum liver function tests (LFTs) were conducted at multiple time points. Results Flow-pressure relationship was established with ΔP of 7.23 mmHg vs 2.33 mmHg (p=0.01) in high-pressure (10 mL/min, HP) and low-pressure (1 mL/min, LP) cohorts. FC assessment of hepatic non-parenchymal cells 1d after infusion demonstrated 15.9% CD3+CAR+ in HP, compared to 5.1% in LP (p=0.0004). Tumor BLI at day 3 (geometric mean relative to baseline) showed significantly enhanced therapeutic effect in HP, −18% relative signal intensity (RSI), compared to +148% RSI in LP (p=0.05) or +178% RSI in controls (p=0.04). LFTs were similar in LP and HP groups with AST 302 vs 437 U/L (p=0.60) and total bilirubin 0.25 vs 0.7 mg/dL (p=0.33), respectively. Conclusions HP delivery correlated with enhanced CAR-T delivery and control of tumor growth, without an increase in liver toxicity. Follow up to this proof of concept study will investigate multiple infusions with combinatorial approaches with the goal of durable tumor eradication. An ongoing clinical study will further explore CAR-T PEDD in patients.

Introduction Checkpoint inhibitors (CI) have greatly impacted the treatment of solid tumors. Success in the liver has been more limited. When intravenously infused, the CI is delivered predominantly to extrahepatic sites, which results in systemic side effects. Previously, we reported on regional delivery of cellular immunotherapy for liver tumors using pressure-enabled drug delivery (PEDD™, TriSalus™ Life Sciences, Inc.). We hypothesized that PEDD of CI would improve the therapeutic index (TI). Methods In a murine model of colorectal liver metastases (CRLM), we infused high (HP) or low pressure (LP) anti-PD-1 antibodies (RMP1-14) via the portal vein and compared to systemic tail vein delivery (SD) at 0, 0.3, 1.0 and 3.0 mg/kg. Tumor bioluminescence (TB), histopathology, and serologic analysis informed treatment effects and toxicity. Results At a dose of 3mg/kg, LP resulted in similar IVIS TB growth kinetics compared to SD 3 mg/kg at 7 days post-treatment (geometric mean, p = 0.94). In animals treated with a 10-fold lower dose (0.3 mg/kg), tumor growth was significantly lower with HP vs. LP (7.5-fold improvement, p = 0.04). Circulating serum anti-PD-1 levels were similar when we compared SD and LP at 1 and 3 mg/kg (Mean 2512.0 vs. 2250.2 ng/mL, p = 0.25). Comparatively, systemic exposure was significantly lower at 0.3 mg/kg LP (Mean 508.1 ng/mL, p < 0.0001). No increases in hepatotoxicity were seen with PEDD (AST p = 0.57, ALT p = 0.43). Conclusion PEDD of anti-PD-1 CI improved liver tumor control while also limiting systemic exposure. These findings support PEDD for anti-PD-1 therapy to improve TI. Phase 1 exploration of anti-PD-1 PEDD for patients with hepatic malignancy is thus warranted.

Liver is a tolerogenic organ and has variety of immune cells resulting in a profoundly immunosuppressive space. We recently reported that GM-CSF/JAK2/STAT3 axis drives liver myeloid suppressor cell (L-MDSC) proliferation and STAT3 inhibition causes activation of apoptosis signaling via Bax up-regulation. Herein, we explore liver specific programming events that promote L-MDSC suppressive conditioning. Bone marrow derived MDSC (BM-MDSC) were expanded in CD45.1+ mice in response to intraperitoneal MC38 tumors. CD45.1+ BM-MDSC were adoptively transferred into CD45.2+ recipient mice via tail vein (TV) or portal vein (PV). CD11b+ cells were harvested 48 hrs later from recipient liver and lungs. Liver from PV and lung from TV CD45.1+ MDSC recipients were compared. There was increased expansion of CD45.1+ MDSC (CD11b+Gr1+) in PV-liver as compared to TV-lung group (Liver-PV 45±3% vs. Lung-TV 15±2% vs. Tumor 43±3, p

Obstructive jaundice is associated with immunologic derangements and hepatic inflammation and fibrosis. Because dendritic cells (DCs) play a major role in immune regulation, we hypothesized that the immunosuppression associated with jaundice may result from the functional impairment of liver DCs. We found that bile duct ligation (BDL) in mice expanded the myeloid subtype of liver DCs from 20 to 80% of total DCs and increased their absolute number by >15-fold. Liver myeloid DCs following BDL, but not sham laparotomy, had increased Ag uptake in vivo, high IL-6 secretion in response to LPS, and enhanced ability to activate T cells. The effects of BDL were specific to liver DCs, as spleen DCs were not affected. Expansion of liver myeloid DCs depended on Gr-1+ cells, and we implicated monocyte chemotactic protein-1 as a potential mediator. Thus, obstructive jaundice selectively expands liver myeloid DCs that are highly functional and unlikely to be involved with impaired host immune responses.

Myeloid derived suppressor cells (MDSC) subvert anti-tumor immunity. Previously we reported that the GM-CSF/ JAK2/STAT3 axis drives liver MDSC (L-MDSC) proliferation and CAR-T suppression. We hypothesized that STAT3 supports L-MDSC survival and suppressive function by inhibiting apoptosis. We treated liver metastasis (LM) in mice with STAT3 inhibitors (STATTIC or BBI) or with vehicle control. STAT3 inhibition caused a significant reduction in tumor burden (p

INTRODUCTION: The mechanism by which obstructive jaundice predisposes to infection has not been clearly defined. We hypothesized that extrahepatic biliary obstruction would directly impair the function of T cells within the liver. METHODS: Bile duct ligation (BDL) or sham laparotomy (SL) was performed in mice. Liver or spleen T cell function was assessed by proliferation in response to dendritic cells or anti-CD3 stimulation. TREG (CD4+CD25+FoxP3+) were measured by flow cytometry. CD4+C25+ (70% FoxP3+) liver T cells were purified by FACS and used as suppressors. RESULTS: Following BDL, liver T cells were markedly less responsive to allogeneic or antigen-loaded syngeneic dendritic cells. In contrast, spleen T cell function was preserved. Even in the presence of direct anti-CD3 stimulation, liver T cells from BDL mice were functionally deficient and produced less IL-2 relative to spleen T cells. BDL expanded the number of liver TREG which suppressed the response of CD4+C25− T cells to DC in vitro. CONCLUSION: BDL expands TREG, which may contribute to the increased risk of infection in patients with obstructive jaundice.