Effect of galectin-1 on prognosis and responsiveness of immune checkpoint plus tyrosine kinase inhibition in renal cell carcinoma.

BACKGROUND: In renal cell carcinoma (RCC), no clinically available biomarker has been utilized for checkpoint inhibitor immunotherapy (IO) + tyrosine kinase inhibitor (TKI) combinations. Galectin-1 overexpression is found in tumors, with potential immune-regulating roles. METHODS: RNA-sequencing was performed in two cohorts of RCC treated with IO/TKI combination therapy (ZS-MRCC, JAVELIN-101). Immunohistochemistry and flow cytometry were performed to investigate immune cell infiltration and function in the tumor microenvironment of RCC. The RECIST criteria were used to define response and progression-free survival (PFS). RESULTS: Galectin-1 expression was elevated in RCC with higher stage (p < 0.001) and grade (p < 0.001). Galectin-1 expression was also elevated in non-responders of IO/TKI therapy (p = 0.047). High galectin-1 was related with shorter PFS in both ZS-MRCC cohort (p = 0.036) and JAVELIN-101 cohort (p = 0.005). Multivariate Cox analysis defined galectin-1 as an independent factor for PFS (HR 2.505; 95% CI 1.116-5.622; p = 0.026). In the tumor microenvironment, high galectin-1 was related with decreased GZMB+CD8+ T cells (Speraman's ρ = -0.31, p = 0.05), and increased PD1 + CD8+ T cells (Speraman's ρ = 0.40, p = 0.01). Besides, elevated number of regulatory T cells (p = 0.039) and fibroblasts (p = 0.011) was also found in high galectin-1 tumors. Finally, a random-forest score (RFscore) was built for predicting IO/TKI benefit. IO/TKI therapy showed benefit only in low-RFscore patients (HR 0.489, 95% CI 0.358-0.669, p < 0.001), rather than high-RFscore patients (HR 0.875, 95% CI 0.658-1.163, p = 0.357). CONCLUSIONS: High galectin-1 indicated therapeutic resistance and shorter PFS of IO/TKI therapy. High galectin-1 also indicated CD8+ T cell dysfunction. High galectin-1 could be applied for patient selection of IO/TKI therapy in RCC.

Single-cell profiling and zebrafish avatars reveal LGALS1 as immunomodulating target in glioblastoma.

Glioblastoma (GBM) remains the most malignant primary brain tumor, with a median survival rarely exceeding 2 years. Tumor heterogeneity and an immunosuppressive microenvironment are key factors contributing to the poor response rates of current therapeutic approaches. GBM-associated macrophages (GAMs) often exhibit immunosuppressive features that promote tumor progression. However, their dynamic interactions with GBM tumor cells remain poorly understood. Here, we used patient-derived GBM stem cell cultures and combined single-cell RNA sequencing of GAM-GBM co-cultures and real-time in vivo monitoring of GAM-GBM interactions in orthotopic zebrafish xenograft models to provide insight into the cellular, molecular, and spatial heterogeneity. Our analyses revealed substantial heterogeneity across GBM patients in GBM-induced GAM polarization and the ability to attract and activate GAMs-features that correlated with patient survival. Differential gene expression analysis, immunohistochemistry on original tumor samples, and knock-out experiments in zebrafish subsequently identified LGALS1 as a primary regulator of immunosuppression. Overall, our work highlights that GAM-GBM interactions can be studied in a clinically relevant way using co-cultures and avatar models, while offering new opportunities to identify promising immune-modulating targets.

TREM2+ macrophages suppress CD8+ T-cell infiltration after transarterial chemoembolisation in hepatocellular carcinoma.

BACKGROUND & AIMS: The immune landscape of hepatocellular carcinoma (HCC) following transarterial chemoembolisation (TACE) remains to be clarified. This study aimed to characterise the immune landscape following TACE and the underlying mechanism of HCC progression. METHODS: Tumour samples from five patients with treatment-naive HCC and five patients who received TACE therapy were collected and subjected to single-cell RNA sequencing. Another 22 paired samples were validated using immunofluorescence staining and flow cytometry. To clarify the underlying mechanisms, in vitro co-culture experiments and two types of TREM2-KO/WT mouse models, namely, an HCC cell orthotopic injection model and a spontaneous HCC model, were used. RESULTS: A reduced number of CD8+ T cells and an increased number of tumour-associated macrophages (TAMs) were observed in the post-TACE microenvironment. TACE therapy reduced the cluster CD8_C4, which was highly enriched with tumour-specific CD8+ T cells of pre-exhausted phenotype. TREM2 was found to be highly expressed in TAMs following TACE, which was associated with a poor prognosis. TREM2+ TAMs secreted less CXCL9 but more galectin-1 than did TREM2- TAMs. Galectin-1 promoted PD-L1 overexpression in vessel endothelial cells, impeding CD8+ T cell recruitment. TREM2 deficiency also increased CD8+ T cell infiltration, which inhibited tumour growth in both in vivo HCC models. More importantly, TREM2 deficiency enhanced the therapeutic effect of anti-PD-L1 blockade. CONCLUSIONS: This study shows that TREM2+ TAMs play an important role in suppressing CD8+ T cells. TREM2 deficiency increased the therapeutic effect of anti-PD-L1 blockade by enhancing antitumour activity of CD8+ T cells. These findings explain the reasons for recurrence and progression after TACE and provide a new target for HCC immunotherapy after TACE. IMPACT AND IMPLICATIONS: Studying the immune landscape in post-TACE HCC is important to uncover the mechanisms of HCC progression. By using scRNA sequencing and functional assays, we discovered that both the number and function of CD8+ T cells are compromised, whereas the number of TREM2+ TAMs is increased in post-TACE HCC, correlating with worse prognosis. Moreover, TREM2 deficiency dramatically increases CD8+ T cell infiltration and augments the therapeutic efficacy of anti-PD-L1 blockade. Mechanistically, TREM2+ TAMs display lower CXCL9 and increased Gal-1 secretion than do TREM2- TAMs, with Gal-1 mediating the overexpression of PD-L1 in vessel endothelial cells. These results suggest that TREM2 could be a novel immunotherapeutic target for patients treated with TACE in HCC. This provides an opportunity to break the plateau of limited therapeutic effect. This study has the value of understanding the tumour microenvironment of post-TACE HCC and thinking a new strategy of immunotherapy in the field of HCC. It is therefore of key impact for physicians, scientists and drug developers in the field of liver cancer and gastrointestinal oncology.

Single-cell analysis reveals the chemotherapy-induced cellular reprogramming and novel therapeutic targets in relapsed/refractory acute myeloid leukemia.

Chemoresistance and relapse are the leading cause of AML-related deaths. Utilizing single-cell RNA sequencing (scRNA-seq), we dissected the cellular states of bone marrow samples from primary refractory or short-term relapsed AML patients and defined the transcriptional intratumoral heterogeneity. We found that compared to proliferating stem/progenitor-like cells (PSPs), a subpopulation of quiescent stem-like cells (QSCs) were involved in the chemoresistance and poor outcomes of AML. By performing longitudinal scRNA-seq analyses, we demonstrated that PSPs were reprogrammed to obtain a QSC-like expression pattern during chemotherapy in refractory AML patients, characterized by the upregulation of CD52 and LGALS1 expression. Flow cytometric analysis further confirmed that the preexisting CD99+CD49d+CD52+Galectin-1+ (QSCs) cells at diagnosis were associated with chemoresistance, and these cells were further enriched in the residual AML cells of refractory patients. Interaction of CD52-SIGLEC10 between QSCs and monocytes may contribute to immune evading and poor outcomes. Furthermore, we identified that LGALS1 was a promising target for chemoresistant AML, and LGALS1 inhibitor could help eliminate QSCs and enhance the chemotherapy in patient-derived primary AML cells, cell lines, and AML xenograft models. Our results will facilitate a better understanding of the AML chemoresistance mechanism and the development of novel therapeutic strategies for relapsed/refractory AML patients.

Pharmacological Characterization of a Novel Neuroactive Steroid Prodrug, NTS-104, and Its Neuroprotective Activity in Experimental Stroke Models.

BACKGROUND: Ischemic stroke affects about 700 000 patients per year in the United States, and to date, there are no effective pharmacological agents that promote recovery. Here, we studied the pharmacokinetics, pharmacodynamics, and efficacy of NTS-105, a novel neuroactive steroid, and NTS-104, a prodrug of NTS-105, in 2 models of ischemic stroke. METHODS: The pharmacodynamics and pharmacokinetics of NTS-104/105 were investigated in naive and stroke rats, and models of embolic and transient middle cerebral artery occlusion were used to investigate the dose-related effects of NTS-104. All rats were randomly assigned into the experimental groups, and all outcome measurements were performed blindly. RESULTS: Blood plasma and brain pharmacokinetic analysis revealed that NTS-104 rapidly converted to NTS-105, which reached peak concentration at ≈1 hour after dosing and distributed similarly to normal and ischemic brains. NTS-104 administration 4 hours after embolic middle cerebral artery occlusion led to a dose-dependent improvement of neurological outcomes and a dose-dependent reduction of infarct volumes relative to vehicle-treated animals. A single dose level study confirmed that NTS-104 administered 4 hours after transient middle cerebral artery occlusion was also neuroprotective. Quantitative ELISA revealed that NTS-104 treatment resulted in time- and dose-dependent changes in AKT activation and cytokine levels within the ischemic brain, which included reductions of IL-6, VEGF, ICAM-1, IL-1ß, MCP-1, RAGE, and GM-CSF. Time- and dose-dependent reductions in IL-6 and GM-CSF were also observed in the plasma along with an elevation of galectin-1. CONCLUSIONS: NTS-104 is a novel prodrug that converts to a novel neuroactive steroid, NTS-105, which improves functional outcomes in experimental ischemic stroke models.

Oligosaccharide-dependent anti-inflammatory role of galectin-1 for macrophages in ulcerative colitis.

BACKGROUND AND AIM: Galectin-1 plays a protective role against colitis by binding with polylactosamine structures on macrophages in ß-1,4-galactosyltransferase I-deficient mice, but the precise function of galectin-1 remains unknown. In the present study, we investigated the anti-inflammatory role of galectin-1 on macrophages to ameliorate ulcerative colitis in both animal model and human tissue samples. METHODS: The expression of galectin-1 in colonic tissues of ulcerative colitis patients was evaluated by immunohistochemistry. Cytokine production of mouse bone marrow-derived macrophages (BMDMs) cultured with galectin-1 was investigated. Galectin-1 binding capacity and polylactosamine expression in macrophages stimulated with lipopolysaccharides were evaluated by flow cytometry. BMDMs cultured with galectin-1 were transferred into Recombination activating gene (Rag) 2-/- mice, and the severity of the dextran sodium sulfate-induced colitis model was investigated. Furthermore, RNA sequencing was performed to characterize macrophages treated with galectin-1. RESULTS: In ulcerative colitis patients, tissue expression of galectin-1was decreased in inflamed mucosa compared with non-inflamed mucosa. Galectin-1 induced interleukin-10 production in BMDMs, and the interleukin-10 production was abrogated by lactose, which inhibits the interaction of oligosaccharide-galectin binding. Dextran sodium sulfate colitis was significantly ameliorated in Rag2-/- mice undergoing galectin-1-treated BMDM transfer compared with those undergoing vehicle-treated BMDM transfer. RNA sequencing revealed that treatment with galectin-1 increased the expression of CCAAT/enhancer binding protein ß and CD163, but decreased the expression of CD80 on BMDMs. CONCLUSION: Galectin-1, whose expression is decreased in the inflamed mucosa of ulcerative colitis patients, can ameliorate murine colitis by conferring oligosaccharide-dependent anti-inflammatory properties to macrophages.

Galectin-1 attenuates neurodegeneration in Parkinson's disease model by modulating microglial MAPK/IκB/NFκB axis through its carbohydrate-recognition domain.

The vicious cycle between the chronicactivationofmicroglia and dopamine neurons degeneration is linked with the progression of Parkinson's disease (PD). Targeting microglialactivationhas proven to be a viable option to develop a disease-modified therapy for PD. Galectin-1, which has been reported to have an anti-neuroinflammation effect was used in the present study to evaluate its therapeutic effects on microglia activation and neuronal degeneration in Parkinson's disease model. It was found that galectin-1 attenuated the inflammatory insult and the apoptosis of SK-N-SH human neuroblastoma cells from conditioned medium of activated microglia induced by Lipopolysaccharides (LPS). Nonetheless, galectin-1 administration (0.5 mg/kg) inhibited the microglia activation, improved the motor deficits in PD mice model induced by MPTP (25 mg/kg weight of mouse, i.p.) and prevented the degeneration of dopaminergic neurons in the substantia nigra. Administration of galectin-1 resulted in p38 and ERK1/2 dephosphorylation followed by IκB/NFκB signaling pathway inhibition. Galectin-1 significantly decreased the secretion of pro-inflammatory cytokines, including interleukin (IL)-1ß, tumor necrosis factor-α (TNF-α), and protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). The protective effects and modulation of the MAPK/IκB/NFκB signaling pathway were abolished with ß-D-galactose which blocked the carbohydrate-recognition domain of galectin-1. The present study demonstrated that galectin-1 inhibited microglia activation and ameliorated neurodegenerative process in PD model by modulating MAPK/IκB/NFκB axis through its carbohydrate-recognition domain.

[Role of galectin-1 in regulation of umbilical cord mesenchymal stem cells on T cells of rheumatoid arthritis].

OBJECTIVE: The therapeutic potential of umbilical cord mesenchymal stem cells (UC-MSCs) in rheumatoid arthritis (RA) has attracted more and more attention, because of it can suppress the various inflammatory effects of T cells. Galectin-1 is highly expressed in UC-MSCs, as the first lectin mediating the immunomodulatory effect of MSCs. Our study will investigate the effects of galectin-1 in regulation of UC-MSCs on rheumatoid arthritis T cells. METHODS: Lentivirus transfected shRNA technique was used to knock down the expression of galectin-1 in UC-MSCs to construct UC-MSCs(Gal-1-). The effects of UC-MSCs and UC-MSCs(Gal-1-) on CD4+ T cells in RA patients were investigated by contact system, including negative control group (CD4+ T cells), positive control group [CD4+ T-phytohemagg lutinin (PHA)], UC-MSCs-CD4+ T cells co-culture group, UC-MSCs(control shRNA)-CD4+ T cells co-culture group, and UC-MSCs(Gal-1-)-CD4+ T cells co-culture group. The proliferation of CD4+ T cells was detected by MTS assay. The level of tumor necrosis factors α (TNF-α) in cells supernatant was detected by enzyme linked immunosorbent assay (ELISA). The effect of UC-MSCs on helper T cell (Th) subset was detected by flow cytometry. RESULTS: In vitro, UC-MSCs were capable of inhibiting PHA induced proliferation of CD4+ T cells from RA patients, but UC-MSCs(Gal-1-) did not show the significant inhibitory effect. Galectin-1 affect the TNF-α level of CD4+ T cells regulated by UC-MSCs. UC-MSCs and UC-MSCs(control shRNA) significantly inhibited the expression of TNF-α in PHA-induced CD4+ T cells. However, UC-MSCs(Gal-1-) had no significant inhibitory effect. Furthermore, the Th1 cells were also significantly suppressed by UC-MSCs and UC-MSCs(control shRNA) (4.83%±1.37% and 5.13%±0.87%,P=0.012 and P=0.018). These was no significant difference in the proportion of the Th1 cells between the control group and UC-MSCs(Gal-1-) group (8.51%±2.04% and 6.41%±0.96%,P=0.101). The Th2 cells were protected after silence galectin-1 in UC-MSCs, whereas there was no significant difference. The proportion of Th17 was decreased by co-culture with UC-MSCs and UC-MSCs (control shRNA), but these was also no significant difference. CONCLUSION: UC-MSCs can inhibit the proliferation and differentiation of CD4+ T cells from RA patients, but these effect declined after knocking down the expression of galectin-1. Galectin-1 maybe take part in the regulation of UC-MSCs on rheumatoid arthritis CD4+ T cells.

Galectin-1 deactivates classically activated microglia and protects from inflammation-induced neurodegeneration.

Inflammation-mediated neurodegeneration occurs in the acute and the chronic phases of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Classically activated (M1) microglia are key players mediating this process. Here, we identified Galectin-1 (Gal1), an endogenous glycan-binding protein, as a pivotal regulator of M1 microglial activation that targets the activation of p38MAPK-, CREB-, and NF-κB-dependent signaling pathways and hierarchically suppresses downstream proinflammatory mediators, such as iNOS, TNF, and CCL2. Gal1 bound to core 2 O-glycans on CD45, favoring retention of this glycoprotein on the microglial cell surface and augmenting its phosphatase activity and inhibitory function. Gal1 was highly expressed in the acute phase of EAE, and its targeted deletion resulted in pronounced inflammation-induced neurodegeneration. Adoptive transfer of Gal1-secreting astrocytes or administration of recombinant Gal1 suppressed EAE through mechanisms involving microglial deactivation. Thus, Gal1-glycan interactions are essential in tempering microglial activation, brain inflammation, and neurodegeneration, with critical therapeutic implications for MS.