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Suppressor of cancer cell invasion (SCAI) acts as a transcriptional repressor of serum response factor (SRF)‐mediated gene expression by binding to megakaryoblastic leukemia (MKL)/myocardin‐related transcription factor (MRTF), which is an SRF transcriptional coactivator. Growing evidence suggests that SCAI is a negative regulator of neuronal morphology, whereas MKL2/MRTFB is a positive regulator. The mRNA expression of SCAI is downregulated during brain development, suggesting that a reduction in SCAI contributes to the reduced suppression of SRF‐mediated gene induction, thus increasing dendritic complexity and developing neuronal circuits. In the present study, we hypothesized that brain‐derived neurotrophic factor (BDNF), which is important for neuronal plasticity and development, might alter SCAI mRNA levels. We therefore investigated the effects of BDNF on SCAI mRNA levels in primary cultured cortical neurons. Furthermore, because alternative splicing generates several SCAI variants in the brain, we measured SCAI variant mRNA after BDNF stimulation. Both SCAI variant 1 and total SCAI mRNA expression levels were downregulated by BDNF. Moreover, the extracellular signal‐regulated protein kinase/mitogen‐activated protein kinase (ERK/MAPK) pathway was involved in the BDNF‐mediated decrease in SCAI mRNA expression. Our findings provide insights into the molecular mechanism underlying a neurotrophic factor switch for the repressive transcriptional complex that includes SCAI. [ABSTRACT FROM AUTHOR]

The most common treatment option for patients with bullous pemphigoid is systemic corticosteroids. CYP3A4, a drug‐metabolizing enzyme in the liver, metabolizes synthetic steroids to a varying degree. Although there are many CYP3A4‐inducing drugs, several antiepileptic drugs, such as phenytoin and phenobarbital, strongly induce CYP3A4, thereby reducing the effects of corticosteroids. Here, we report a case of refractory bullous pemphigoid that rapidly improved after the discontinuation of phenytoin and phenobarbital. To achieve adequate pharmacological effects of corticosteroids, we must always ensure that patients who require corticosteroids for treatment are not medicated with CYP3A4‐inducing agents. [ABSTRACT FROM AUTHOR]

In dermatology, biologics that block signaling pathways of TNF‐α, IL‐4/IL13, IL‐17s, and IL‐23 are widely used for the treatment of several inflammatory skin diseases, such as atopic dermatitis and psoriasis. They have shown excellent efficacy with an acceptable safety profile. However, these biologics targeting pathogenic cytokines and their receptors could modulate immunological balance, leading to the development of other inflammatory or autoimmune skin diseases in some cases. In this study, we present a patient who suffered pemphigus vegetans and showed an exacerbation of pemphigus foliaceus after secukinumab loading for the treatment of complicated generalized pustular psoriasis and pyoderma gangrenosum. [ABSTRACT FROM AUTHOR]

Megakaryoblastic leukemia 2 (MKL2)/myocardin‐related transcription factor‐B (MRTFB), a serum response factor (SRF) coactivator, is an important regulator of gene expression and neuronal morphology. Here, we show that different mouse MRTFB splice isoforms, including a novel fourth MRTFB isoform named spliced neuronal long isoform of SRF transcriptional coactivator (SOLOIST)/MRTFB isoform 4 (MRTFB i4), play distinct roles in this process. SOLOIST/MRTFB i4 has a short exon that encodes 21 amino acid residues ahead of the first RPXXXEL (RPEL) motif in MRTFB isoform 3. Quantitative PCR revealed that SOLOIST/MRTFB i4 and isoform 1 were enriched in the forebrain and neurons, and up‐regulated during brain development. Conversely, isoform 3 was detected in various tissues, including both neurons and astrocytes, and was down‐regulated in the developing brain. Reporter assays supported the SRF‐coactivator function of SOLOIST/MRTFB i4 as well as isoform 1. Acute expression of MRTFB isoform 1, but not isoform 3 or SOLOIST/MRTFB i4, in neuronal cells within 24 hr drastically increased endogenous immediate early gene [c‐fos, egr1, and activity‐regulated cytoskeleton‐associated protein] expression, but not endogenous actinin α1, β‐actin, gelsolin, or srf gene expression measured by qPCR. Over‐expression of SOLOIST/MRTFB i4 reduced the dendritic complexity of cortical neurons, whereas over‐expression of isoform 1 increased this complexity. Co‐expression of isoform 1 and SOLOIST/MRTFB i4 in cortical neurons revealed that isoform 1 competitively counteracted down‐regulation by SOLOIST/MRTFB i4. Our findings indicate that MRTFB isoforms have unique expression patterns and differential effects on gene expression and dendritic complexity, which contribute to shaping neuronal circuits, at least in part. [ABSTRACT FROM AUTHOR]

The expression of immediate early genes (IEGs) is thought to be an essential molecular basis of neuronal plasticity for higher brain function. Many IEGs contain serum response element in their transcriptional regulatory regions and their expression is controlled by serum response factor (SRF). SRF is known to play a role in concert with transcriptional cofactors. However, little is known about how SRF cofactors regulate IEG expression during the process of neuronal plasticity. We hypothesized that one of the SRF‐regulated neuronal IEGs, activity‐regulated cytoskeleton‐associated protein (Arc; also termed Arg3.1), is regulated by an SRF coactivator, megakaryoblastic leukemia (MKL). To test this hypothesis, we initially investigated which binding site of the transcription factor or SRF cofactor contributes to brain‐derived neurotrophic factor (BDNF)‐induced Arc gene transcription in cultured cortical neurons using transfection and reporter assays. We found that BDNF caused robust induction of Arc gene transcription through a cAMP response element, binding site of myocyte enhancer factor 2, and binding site of SRF in an Arc enhancer, the synaptic activity‐responsive element (SARE). Regardless of the requirement for the SRF‐binding site, the binding site of a ternary complex factor, another SRF cofactor, did not affect BDNF‐mediated Arc gene transcription. In contrast, chromatin immunoprecipitation revealed occupation of MKL at the SARE. Furthermore, knockdown of MKL2, but not MKL1, significantly decreased BDNF‐mediated activation of the SARE. Taken together, these findings suggest a novel mechanism by which MKL2 controls the Arc SARE in response to BDNF stimulation. The activity‐regulated cytoskeleton‐associated protein (Arc) gene is a serum response factor (SRF) target, but little is known about its transcriptional regulation by SRF cofactors. Here, we demonstrate that SRF cofactor megakaryoblastic leukemia 2 (MKL2) binds to the Arc gene enhancer, a synaptic activity‐responsive element (SARE), and mediates brain‐derived neurotrophic factor (BDNF)‐induced Arc SARE activation. [ABSTRACT FROM AUTHOR]

Mice lacking the gene encoding pituitary adenylate cyclase-activating polypeptide ( PACAP) or its specific receptor, PAC1, show abnormal behaviors related to schizophrenia. However, the regulation of PACAP expression in neurons remains unclear. Here, we report that Pacap mRNA levels are regulated transcriptionally and post-transcriptionally by cAMP and Ca2+ signals in cultured rat cortical cells. Pacap mRNA levels decreased proportionately with the intensity of cAMP signaling, and this decrease was accelerated by N-methyl-D-aspartate (NMDA) receptor blockade, suggesting that cAMP signaling enhances the degradation of Pacap mRNA, whereas NMDA receptor-mediated signals inhibit its degradation. However, depolarization (which produced a robust increase in Ca2+ signals) together with cAMP signaling resulted in a synergistic induction of Pacap mRNA through calcineurin and its substrate, cAMP-response element-binding protein ( CREB)-regulated transcription coactivator 1. These results strongly support the concept that while cAMP signaling can accelerate the degradation of Pacap mRNA, it can also synergistically enhance Ca2+ signaling-induced transcriptional activation of Pacap. Taken together, our findings suggest that a balance between Ca2+ and cAMP signals regulates PACAP levels in neurons and that a perturbation of this balance may result in psychiatric disorders, such as schizophrenia. [ABSTRACT FROM AUTHOR]

Immune checkpoint inhibitors (ICIs) exert clinical efficacy against various types of cancers by reinvigorating exhausted CD8 + T cells that can expand and directly attack cancer cells (cancer-specific T cells) among tumor-infiltrating lymphocytes (TILs). Although some reports have identified somatic mutations in TILs, their effect on antitumor immunity remains unclear. In this study, we successfully established 18 cancer-specific T cell clones, which have an exhaustion phenotype, from the TILs of four patients with melanoma. We conducted whole-genome sequencing for these T cell clones and identified various somatic mutations in them with high clonality. Among the somatic mutations, an SH2D2A loss-of-function frameshift mutation and TNFAIP3 deletion could activate T cell effector functions in vitro. Furthermore, we generated CD8 + T cell-specific Tnfaip3 knockout mice and showed that Tnfaip3 function loss in CD8 + T cell increased antitumor immunity, leading to remarkable response to PD-1 blockade in vivo. In addition, we analyzed bulk CD3 + T cells from TILs in additional 12 patients and identified an SH2D2A mutation in one patient through amplicon sequencing. These findings suggest that somatic mutations in TILs can affect antitumor immunity and suggest unique biomarkers and therapeutic targets., Competing Interests: Competing interests statement:K. Yamashita is an employee of KOTAI Biotechnologies. T. Inozume received honoraria from Ono Pharmaceutical, Bristol-Myers Squibb, and MSD outside of this study. H. Mano is a board member of CureGene; and received honoraria from Konica Minolta outside of this study. S. Toyooka received honoraria from TAIHO PHARMA, Eli Lilly, Chugai Pharmaceutical, GUARDANT, AstraZeneca, Illumina, MERCK, CSL Behring, Johnson & Johnson, Nippon Kayaku, INTUITIVE, Daiichi-Sankyo, ONO PHARMACEUTICAL, Medtronic, Ziosoft, NOVARTIS, Sysmex, and Riken Genesis outside of this study. Y. Togashi received honoraria from Ono Pharmaceutical and Bristol-Myers Squibb, AstraZeneca, Chugai Pharmaceutical, and MSD outside of this study. H. Mano received research grants from Daiichi Sankyo, Konica Minolta, Ambry Genetics, Ono Pharmaceutical and PFDeNA outside of this study. S. Toyooka received research grants from TAIHO PHARMA, Eli Lilly, Chugai Pharmaceutical, and Astellas Pharma outside of this study. Y. Togashi received research grants from Ono Pharmaceutical, Bristol-Myers Squibb, Daiichi-Sankyo, Janssen Pharmaceutical, AstraZeneca, KOTAI, and KORTUC outside of this study. The other authors declare that they have no research support relevant to financial competing interests.

Actin rearrangement and phosphorylation-dephosphorylation in the nervous system contribute to plastic alteration of neuronal structure and function. Phosphatase and actin regulator (PHACTR) family members are actin- and protein phosphatase 1 (PP1)-binding proteins. Because some family members act as regulators of neuronal morphology, studying the regulatory mechanisms of PHACTR is valuable for understanding the basis of neuronal circuit formation. Although expression patterns of PHACTR family molecules (PHACTR1-4) vary across distinct brain areas, little is known about the extracellular ligands that influence their mRNA levels. In this study, we focused on an important neurotrophin, brain-derived neurotrophic factor (BDNF), and examined its effect on mRNA expression of PHACTR family member in cortical neurons. PHACTR1-3, but not PHACTR4, were affected by stimulation of primary cultured cortical neurons with BDNF; namely, sustained downregulation of their mRNA levels was observed. The observed downregulation was blocked by an inhibitor of the extracellular signal-regulated protein kinase/mitogen-activated protein kinase (ERK/MAPK) pathway, U0126, suggesting that ERK/MAPK plays an inhibitory role for gene induction of PHACTR1-3. These findings aid the elucidation of how BDNF regulates actin- and PP1-related neuronal functions.

T-cell exhaustion is a major contributor to immunosuppression in the tumor microenvironment (TME). Blockade of key regulators of T-cell exhaustion, such as programmed death 1, can reinvigorate tumor-specific T cells and activate antitumor immunity in various types of cancer. In this study, we identified that CD106 was specifically expressed in exhausted CD8+ T cells in the TME using single-cell RNA sequencing. High CD106 expression in the TME in clinical samples corresponded to improved response to cancer immunotherapy. CD106 in tumor-specific T cells suppressed antitumor immunity both in vitro and in vivo, and loss of CD106 in CD8+ T cells suppressed tumor growth and improved response to programmed death 1 blockade. Mechanistically, CD106 inhibited T-cell receptor (TCR) signaling by interacting with the TCR/CD3 complex and reducing its surface expression. Together, these findings provide insights into the immunosuppressive role of CD106 expressed in tumor-specific exhausted CD8+ T cells, identifying it as a potential biomarker and therapeutic target for cancer immunotherapy. Significance: CD106 is specifically expressed in tumor-specific exhausted CD8+ T cells and inhibits the TCR signaling pathway by reducing surface expression of the TCR/CD3 complex to suppress antitumor immunity., (©2024 American Association for Cancer Research.)

Mice lacking the gene encoding pituitary adenylate cyclase-activating polypeptide (PACAP) or its specific receptor, PAC1, show abnormal behaviors related to schizophrenia. However, the regulation of PACAP expression in neurons remains unclear. Here, we report that Pacap mRNA levels are regulated transcriptionally and post-transcriptionally by cAMP and Ca(2+) signals in cultured rat cortical cells. Pacap mRNA levels decreased proportionately with the intensity of cAMP signaling, and this decrease was accelerated by N-methyl-D-aspartate (NMDA) receptor blockade, suggesting that cAMP signaling enhances the degradation of Pacap mRNA, whereas NMDA receptor-mediated signals inhibit its degradation. However, depolarization (which produced a robust increase in Ca(2+) signals) together with cAMP signaling resulted in a synergistic induction of Pacap mRNA through calcineurin and its substrate, cAMP-response element-binding protein (CREB)-regulated transcription coactivator 1. These results strongly support the concept that while cAMP signaling can accelerate the degradation of Pacap mRNA, it can also synergistically enhance Ca(2+) signaling-induced transcriptional activation of Pacap. Taken together, our findings suggest that a balance between Ca(2+) and cAMP signals regulates PACAP levels in neurons and that a perturbation of this balance may result in psychiatric disorders, such as schizophrenia., (© 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.)

Although coordinated molecular signaling through excitatory and modulatory neurotransmissions is critical for the induction of immediate early genes (IEGs), which lead to effective changes in synaptic plasticity, the intracellular mechanisms responsible remain obscure. Here we measured the expression of IEGs and used bioluminescence imaging to visualize the expression of Bdnf when GPCRs, major neuromodulator receptors, were stimulated. Stimulation of pituitary adenylate cyclase-activating polypeptide (PACAP)-specific receptor (PAC1), a Gαs/q-protein-coupled GPCR, with PACAP selectively activated the calcineurin (CN) pathway that is controlled by calcium signals evoked via NMDAR. This signaling pathway then induced the expression of Bdnf and CN-dependent IEGs through the nuclear translocation of CREB-regulated transcriptional coactivator 1 (CRTC1). Intracerebroventricular injection of PACAP and intraperitoneal administration of MK801 in mice demonstrated that functional interactions between PAC1 and NMDAR induced the expression of Bdnf in the brain. Coactivation of NMDAR and PAC1 synergistically induced the expression of Bdnf attributable to selective activation of the CN pathway. This CN pathway-controlled expression of Bdnf was also induced by stimulating other Gαs- or Gαq-coupled GPCRs, such as dopamine D1, adrenaline β, CRF, and neurotensin receptors, either with their cognate agonists or by direct stimulation of the protein kinase A (PKA)/PKC pathway with chemical activators. Thus, the GPCR-induced expression of IEGs in coordination with NMDAR might occur via the selective activation of the CN/CRTC1/CREB pathway under simultaneous excitatory and modulatory synaptic transmissions in neurons if either the Gαs/adenylate cyclase/PKA or Gαq/PLC/PKC-mediated pathway is activated., (Copyright © 2015 the authors 0270-6474/15/355606-19$15.00/0.)