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Although CD4+CD25+FOXP3+ regulatory T (TREG) cells have been studied in patients with COVID-19, changes in the TREG cell population have not been longitudinally examined during the course of COVID-19. In this study, we longitudinally investigated the quantitative and qualitative changes in the TREG cell population in patients with COVID-19. We found that the frequencies of total TREG cells and CD45RA−FOXP3hi activated TREG cells were significantly increased 15–28 d postsymptom onset in severe patients, but not in mild patients. TREG cells from severe patients exhibited not only increased proliferation but also enhanced apoptosis, suggesting functional derangement of the TREG cell population during severe COVID-19. The suppressive functions of the TREG cell population did not differ between patients with severe versus mild COVID-19. The frequency of TREG cells inversely correlated with SARS-CoV-2–specific cytokine production by CD4+ T cells and their polyfunctionality in patients with mild disease, suggesting that TREG cells are major regulators of virus-specific CD4+ T cell responses during mild COVID-19. However, such correlations were not observed in patients with severe disease. Thus, in this study, we describe distinctive changes in the TREG cell population in patients with severe and mild COVID-19. Our study provides a deep understanding of host immune responses upon SARS-CoV-2 infection in regard to TREG cells.

Purpose: Regulatory T cells (Tregs) exert immunosuppressive functions and hamper antitumor immune responses in the tumor microenvironment. Understanding the heterogeneity of intratumoral Tregs, and how it changes with tumor progression, will provide clues regarding novel target molecules of Treg-directed therapies. Experimental Design: From 42 patients with renal cell carcinoma and 5 patients with ovarian cancer, immune cells from tumor and peripheral blood were isolated. We performed multicolor flow cytometry and RNA-sequencing to characterize the phenotypes and heterogeneity of intratumoral Tregs. In vitro functional assays were performed to evaluate suppressive capacity of Tregs and effect of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-mediated depletion. The CT26 tumor model was used to evaluate the association between intratumoral Tregs and tumor growth, and examine the in vivo role of CEACAM1+ intratumoral Tregs on antitumor immunity. Results: We found that CEACAM1 was selectively expressed on intratumoral Tregs, whereas its expression on peripheral Tregs or other immune cells was low. The CEACAM1+ intratumoral Tregs accumulated with tumor progression, whereas the CEACAM1− subset did not. Notably, we found that CEACAM1 marked intratumoral Tregs that exhibited highly suppressive and activated phenotypes with substantial clonal expansion. Depletion of CEACAM1-expressing cells from tumor-infiltrating leukocytes led to increased effector functions of tumor-infiltrating T cells. Moreover, CEACAM1+ cell depletion further enhanced anti-PD-1–mediated reinvigoration of exhausted CD8+ T cells. Conclusions: CEACAM1 marks highly suppressive subset of intratumoral Tregs, and can be a target for selective depletion of intratumoral Tregs. These results may inform future studies on CEACAM1-mediated depletion in patients with cancer.

The liver provides a unique niche of lymphocytes enriched with a large proportion of innate-like T cells. However, the heterogeneity and functional characteristics of the hepatic T-cell population remain to be fully elucidated.We obtained liver sinusoidal mononuclear cells from the liver perfusate of healthy donors and recipients with HBV-associated chronic liver disease (CLD) during liver transplantation. We performed a CITE-seq analysis of liver sinusoidal CD45We identified a distinct CD56In summary, the current study found a distinct CD56The role of different immune cell populations in the liver is becoming an area of increasing interest. Herein, we identified a distinct T-cell population that had features similar to those of natural killer (NK) cells - a type of innate immune cell. This distinct population was expanded in the livers of patients with chronic liver disease and could thus have pathogenic relevance.

Purpose:Regulatory T cells (Tregs) exert immunosuppressive functions and hamper antitumor immune responses in the tumor microenvironment. Understanding the heterogeneity of intratumoral Tregs, and how it changes with tumor progression, will provide clues regarding novel target molecules of Treg-directed therapies.Experimental Design:From 42 patients with renal cell carcinoma and 5 patients with ovarian cancer, immune cells from tumor and peripheral blood were isolated. We performed multicolor flow cytometry and RNA-sequencing to characterize the phenotypes and heterogeneity of intratumoral Tregs. In vitro functional assays were performed to evaluate suppressive capacity of Tregs and effect of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-mediated depletion. The CT26 tumor model was used to evaluate the association between intratumoral Tregs and tumor growth, and examine the in vivo role of CEACAM1+ intratumoral Tregs on antitumor immunity.Results:We found that CEACAM1 was selectively expressed on intratumoral Tregs, whereas its expression on peripheral Tregs or other immune cells was low. The CEACAM1+ intratumoral Tregs accumulated with tumor progression, whereas the CEACAM1− subset did not. Notably, we found that CEACAM1 marked intratumoral Tregs that exhibited highly suppressive and activated phenotypes with substantial clonal expansion. Depletion of CEACAM1-expressing cells from tumor-infiltrating leukocytes led to increased effector functions of tumor-infiltrating T cells. Moreover, CEACAM1+ cell depletion further enhanced anti-PD-1–mediated reinvigoration of exhausted CD8+ T cells.Conclusions:CEACAM1 marks highly suppressive subset of intratumoral Tregs, and can be a target for selective depletion of intratumoral Tregs. These results may inform future studies on CEACAM1-mediated depletion in patients with cancer.

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Despite being a standard treatment option in breast cancer, immune checkpoint inhibitors (ICIs) are only efficacious for a subset of patients. To gain a better understanding of the antitumor immune response in breast cancer, we examined the heterogeneity of CD8

Despite being a standard treatment option in breast cancer, immune checkpoint inhibitors (ICIs) are only efficacious for a subset of patients. To gain a better understanding of the antitumor immune response in breast cancer, we examined the heterogeneity of CD8 + T cells in tumors, metastatic lymph nodes (mLNs), and peripheral blood from patients with early breast cancer ( n = 131). Among tissue-resident memory CD8 + T (T RM ) cells, including virus- and tumor-specific CD8 + T cells, CD39 expression was observed in a tumor-specific and exhausted subpopulation in both tumors and mLNs. CD39 + T RM cells from tumors and mLNs exhibited a phenotypic similarity and clonally overlapped with each other. Moreover, tumor or mLN CD39 + T RM cells clonally overlapped with CD39 − T RM and non-T RM cells in the same compartment, implying a tissue-specific differentiation process. These inter-subpopulationally overlapping CD39 + T RM clonotypes were frequently detected among effector memory CD8 + T cells in peripheral blood, suggesting a systemic clonal overlap. CD39 + T RM cell enrichment was heterogeneous among molecular subtypes of breast cancer, which is associated with the different role of antitumor immune responses in each subtype. In vitro blockade of PD-1 and/or CTLA-4 effectively restored proliferation of CD39 + T RM cells and enhanced cytokine production by CD8 + T cells from tumors or mLNs, particularly in the presence of CD39 + T RM enrichment. This suggests that CD39 + T RM cells have a capacity for functional restoration upon ICI treatment. Thus, our study indicates that CD39 + T RM cells with a clonal overlap across compartments are key players in antitumor immunity in breast cancer.

Immune checkpoint inhibitors are effective for advanced hepatocellular carcinoma (HCC), but there remains a need for peripheral blood biomarkers to predict the clinical response. Here, we analyzed the peripheral blood of 45 patients with advanced HCC who underwent nivolumab. During treatment, frequency of classical monocytes (CD14

During spinal cord development, Sonic hedgehog (Shh), secreted from the floor plate, plays an important role in the production of motor neurons by patterning the ventral neural tube, which establishes MN progenitor identity. It remains unknown, however, if Shh signaling plays a role in generating columnar diversity of MNs that connect distinct target muscles. Here, we report that Shh, expressed in MNs, is essential for the formation of lateral motor column (LMC) neurons in vertebrate spinal cord. This novel activity of Shh is mediated by its downstream effector ARHGAP36, whose expression is directly induced by the MN-specific transcription factor complex Isl1-Lhx3. Furthermore, we found that AKT stimulates the Shh activity to induce LMC MNs through the stabilization of ARHGAP36 proteins. Taken together, our data reveal that Shh, secreted from MNs, plays a crucial role in generating MN diversity via a regulatory axis of Shh-AKT-ARHGAP36 in the developing mouse spinal cord.

Tissue-resident memory CD8+ T cells (TRMs), marked by expression of CD103, are considered to play a key role as anti-tumor immune response in breast cancer. However, prognostic value of TRMs and heterogeneity in CD103+ TRMs of breast cancer in terms of tumor-specificity needs further understanding to establish immuno-therapeutic implications. Here, we isolated tumor-infiltrating CD103+TRMs in breast cancer samples and matched peripheral blood mononuclear cells (PBMCs) which were prospectively collected from 127 patients who underwent surgical resection between July 2016 and May 2020 at Severance Hospital, Seoul, Republic of Korea. Multi-color flow cytometry analyses were performed.CD103+TRMs consist of both tumor-antigen specific CD8+ T cells and bystander CD8+ T cells, such as viral antigen-specific CD8+ T cells. Dissection of CD103+TRMs with CD39 expression reveals a clonally-distinct subpopulation exhibiting tumor-antigen specificity and reactivity with transcriptionally and phenotypically exhaustive features. CD39+CD103+ TRMs were enriched in HER2 enriched and triple-negative breast cancer(TNBC) subtypes, but not in Hormone receptor(HR) positive/HER2 not enriched subtypes, implying that the role of tumor-infiltrating CD8+ T cells in eliciting anti-tumor immune response differ among molecular subtypes. In line with early-exhaustive features of CD39+CD103+TRMs, inhibition of either PD-1 alone or both PD-1 and CTLA-4 reinvigorate the proliferation and the cytokine production of CD8+ TILs in HER2 and TNBC subtypes. Our findings indicate that different immuno-therapeutic strategies should be considered to different subtypes of breast cancer. Citation Format: Jee Ye Kim, Yong Joon Lee, Seung hyuck Jeon, Heejin Nam, Jae Hyung Jung, Seung Il Kim, Eui-Cheol Shin. Tumor-specificity of tumor-infiltrating CD8+ t cells determines the potential of immune checkpoint inhibitors in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1666.

This paper describes one of the hot issues in solar cell studies, dye-sensitized solar cell. DSSC is a kind of photoelectrochemical cells. Therefore, it is quite different from the conventional solar cells which originate from pn semiconductor theory, although its mechanism can be explained with the theory. This paper describes the difference between the conventional semiconductor approaches and a newly adapted one for DSSC. Especially, electrochemical analysis methods such as electrochemical impedance analysis and cyclic voltammogram are briefly introduced, which are commonly used for DSSC analysis.

During spinal cord development, motor neuron (MN) axons exit the spinal cord ventrally, although the molecular basis for this process remains poorly understood. STAM1 and Hrs form a complex involved with endosomal targeting of cargo proteins, including the chemokine receptor CXCR4. Interestingly, the absence of CXCR4 signaling in spinal MNs is known to enforce improper extension of the axons into the dorsal side of the spinal cord. Here we report that the MN-specific Isl1-Lhx3 complex directly transactivates the Stam1 gene and STAM1 functions in determining the ventral spinal MN axonal projections. STAM1 is co-expressed with Hrs in embryonic spinal MNs, and knock-down of STAM1 in the developing chick spinal cord results in down-regulation of the expression of CXCR4, accompanied by dorsally projecting motor axons. Interestingly, overexpression of STAM1 or CXCR4 also results in dorsal projection of motor axons, suggesting that proper CXCR4 protein level is critical for the ventral motor axon trajectory. Our results reveal a critical regulatory axis for the ventral axonal trajectory of developing spinal MNs, consisting of the Isl1-Lhx3 complex, STAM1 and CXCR4.

While microRNAs have emerged as an important component of gene regulatory networks, it remains unclear how microRNAs collaborate with transcription factors in the gene networks that determines neuronal cell fate. Here we show that in the developing spinal cord, the expression of miR-218 is directly upregulated by the Isl1-Lhx3 complex, which drives motor neuron fate. Inhibition of miR-218 suppresses the generation of motor neurons in both chick neural tube and mouse embryonic stem cells, suggesting that miR-218 plays a crucial role in motor neuron differentiation. Results from unbiased RISC-trap screens, in vivo reporter assays and overexpression studies indicated that miR-218 directly represses transcripts that promote developmental programs for interneurons. In addition, we found that miR-218 activity is required for Isl1-Lhx3 to effectively induce motor neurons and suppress interneuron fates. Together our results reveal an essential role of miR-218 as a downstream effector of the Isl1-Lhx3 complex in establishing motor neuron identity.

While microRNAs have emerged as an important component of gene regulatory networks, it remains unclear how microRNAs collaborate with transcription factors in the gene networks that determines neuronal cell fate. Here we show that in the developing spinal cord, the expression of miR-218 is directly upregulated by the Isl1–Lhx3 complex, which drives motor neuron fate. Inhibition of miR-218 suppresses the generation of motor neurons in both chick neural tube and mouse embryonic stem cells, suggesting that miR-218 plays a crucial role in motor neuron differentiation. Results from unbiased RISC-trap screens, in vivo reporter assays and overexpression studies indicated that miR-218 directly represses transcripts that promote developmental programs for interneurons. In addition, we found that miR-218 activity is required for Isl1–Lhx3 to effectively induce motor neurons and suppress interneuron fates. Together our results reveal an essential role of miR-218 as a downstream effector of the Isl1–Lhx3 complex in establishing motor neuron identity. microRNAs have emerged as important components of numerous gene regulatory networks. Here the authors demonstrate that miR-218 is an essential component of the gene regulatory network that controls motor neuron fate specification in the developing spinal cord.

The establishment of correct neurotransmitter characteristics is an essential step of neuronal fate specification in CNS development. However, very little is known about how a battery of genes involved in the determination of a specific type of chemical-driven neurotransmission is coordinately regulated during vertebrate development. Here, we investigated the gene regulatory networks that specify the cholinergic neuronal fates in the spinal cord and forebrain, specifically, spinal motor neurons (MNs) and forebrain cholinergic neurons (FCNs). Conditional inactivation of Isl1, a LIM homeodomain factor expressed in both differentiating MNs and FCNs, led to a drastic loss of cholinergic neurons in the developing spinal cord and forebrain. We found that Isl1 forms two related, but distinct types of complexes, the Isl1-Lhx3-hexamer in MNs and the Isl1-Lhx8-hexamer in FCNs. Interestingly, our genome-wide ChIP-seq analysis revealed that the Isl1-Lhx3-hexamer binds to a suite of cholinergic pathway genes encoding the core constituents of the cholinergic neurotransmission system, such as acetylcholine synthesizing enzymes and transporters. Consistently, the Isl1-Lhx3-hexamer directly coordinated upregulation of cholinergic pathways genes in embryonic spinal cord. Similarly, in the developing forebrain, the Isl1-Lhx8-hexamer was recruited to the cholinergic gene battery and promoted cholinergic gene expression. Furthermore, the expression of the Isl1-Lhx8-complex enabled the acquisition of cholinergic fate in embryonic stem cell-derived neurons. Together, our studies show a shared molecular mechanism that determines the cholinergic neuronal fate in the spinal cord and forebrain, and uncover an important gene regulatory mechanism that directs a specific neurotransmitter identity in vertebrate CNS development., Author Summary Neurons utilize various chemicals to transmit signals to a target cell. Distinct types of neurons in the spinal cord and forebrain, collectively termed cholinergic neurons, utilize the same chemical, acetylcholine, for signal transmission. These neurons play critical roles in controlling locomotion and cognition. In this study, we have found that the Isl1 gene orchestrates the process to generate cholinergic neurons in the spinal cord and forebrain. Isl1 forms two different types of multi-protein complexes in the spinal cord and forebrain. Both complexes bind the same genomic regions in a group of genes critical for cholinergic signal transmission, and promote their simultaneous expression. These cholinergic genes include enzymes that synthesize acetylcholine and proteins required to package acetylcholine into vesicles. The Isl1-containing multi-protein complexes were able to trigger the generation of cholinergic neurons in embryonic stem cells and neural stem cells. Our study reveals crucial mechanisms to coordinate the expression of genes in the same biological pathway in different cell types. Furthermore, it suggests a new strategy to produce cholinergic neurons from stem cells.