Functional Roles of CD26/DPP4 in Bleomycin-Induced Pulmonary Hypertension Associated with Interstitial Lung Disease.

Pulmonary hypertension (PH) with interstitial lung diseases (ILDs) often causes intractable conditions. CD26/Dipeptidyl peptidase-4 (DPP4) is expressed in lung constituent cells and may be related to the pathogenesis of various respiratory diseases. We aimed to clarify the functional roles of CD26/DPP4 in PH-ILD, paying particular attention to vascular smooth muscle cells (SMCs). Dpp4 knockout (Dpp4KO) and wild type (WT) mice were administered bleomycin (BLM) intraperitoneally to establish a PH-ILD model. The BLM-induced increase in the right ventricular systolic pressure and the right ventricular hypertrophy observed in WT mice were attenuated in Dpp4KO mice. The BLM-induced vascular muscularization in small pulmonary vessels in Dpp4KO mice was milder than that in WT mice. The viability of TGFß-stimulated human pulmonary artery SMCs (hPASMCs) was lowered due to the DPP4 knockdown with small interfering RNA. According to the results of the transcriptome analysis, upregulated genes in hPASMCs with TGFß treatment were related to pulmonary vascular SMC proliferation via the Notch, PI3K-Akt, and NFκB signaling pathways. Additionally, DPP4 knockdown in hPASMCs inhibited the pathways upregulated by TGFß treatment. These results suggest that genetic deficiency of Dpp4 protects against BLM-induced PH-ILD by alleviating vascular remodeling, potentially through the exertion of an antiproliferative effect via inhibition of the TGFß-related pathways in PASMCs.

Pathophysiological Roles of Stress-Activated Protein Kinases in Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is one of the most symptomatic progressive fibrotic lung diseases, in which patients have an extremely poor prognosis. Therefore, understanding the precise molecular mechanisms underlying pulmonary fibrosis is necessary for the development of new therapeutic options. Stress-activated protein kinases (SAPKs), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38) are ubiquitously expressed in various types of cells and activated in response to cellular environmental stresses, including inflammatory and apoptotic stimuli. Type II alveolar epithelial cells, fibroblasts, and macrophages are known to participate in the progression of pulmonary fibrosis. SAPKs can control fibrogenesis by regulating the cellular processes and molecular functions in various types of lung cells (including cells of the epithelium, interstitial connective tissue, blood vessels, and hematopoietic and lymphoid tissue), all aspects of which remain to be elucidated. We recently reported that the stepwise elevation of intrinsic p38 signaling in the lungs is correlated with a worsening severity of bleomycin-induced fibrosis, indicating an importance of this pathway in the progression of pulmonary fibrosis. In addition, a transcriptome analysis of RNA-sequencing data from this unique model demonstrated that several lines of mechanisms are involved in the pathogenesis of pulmonary fibrosis, which provides a basis for further studies. Here, we review the accumulating evidence for the spatial and temporal roles of SAPKs in pulmonary fibrosis.

Transcriptomic Evaluation of Pulmonary Fibrosis-Related Genes: Utilization of Transgenic Mice with Modifying p38 Signal in the Lungs.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing lung disease that is caused by the dysregulation of alveolar epithelial type II cells (AEC II). The mechanisms involved in the progression of IPF remain incompletely understood, although the immune response accompanied by p38 mitogen-activated protein kinase (MAPK) activation may contribute to some of them. This study aimed to examine the association of p38 activity in the lungs with bleomycin (BLM)-induced pulmonary fibrosis and its transcriptomic profiling. Accordingly, we evaluated BLM-induced pulmonary fibrosis during an active fibrosis phase in three genotypes of mice carrying stepwise variations in intrinsic p38 activity in the AEC II and performed RNA sequencing of their lungs. Stepwise elevation of p38 signaling in the lungs of the three genotypes was correlated with increased severity of BLM-induced pulmonary fibrosis exhibiting reduced static compliance and higher collagen content. Transcriptome analysis of these lung samples also showed that the enhanced p38 signaling in the lungs was associated with increased transcription of the genes driving the p38 MAPK pathway and differentially expressed genes elicited by BLM, including those related to fibrosis as well as the immune system. Our findings underscore the significance of p38 MAPK in the progression of pulmonary fibrosis.

Antifibrotic effects of cyclosporine A on TGF-ß1-treated lung fibroblasts and lungs from bleomycin-treated mice: role of hypoxia-inducible factor-1α.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disorder that is characterized by aberrant tissue remodeling and the formation of fibroblastic foci that are composed of fibrogenic myofibroblasts. TGF-ß1 is one of the factors that are responsible for fibrosis as it promotes fibroblast to myofibroblast differentiation (FMD) and is associated with up-regulation of α-smooth muscle actin. Therefore, inhibition of FMD may represent an effective strategy for the treatment of IPF. Here, we describe the treatment of human lung fibroblasts (WI-38 and HFL-1 cells) with cyclosporine A (CsA), which reduces TGF-ß1-induced FMD via degradation of hypoxia-inducible factor-1α (HIF-1α). In addition, in primary myofibroblast-like cells that were obtained from a patient with pulmonary fibrosis, treatment with CsA and an HIF-1α inhibitor (HIFi) decreased the expression levels of α-smooth muscle actin and fibronectin, which indicated that CsA and HIFi promote dedifferentiation of myofibroblasts. In mice intratracheally administered CsA or HIFi at an early fibrotic stage [7, 8, and 9 d postinstillation (dpi) of bleomycin], marked alleviation of lung fibrosis was observed at 14 dpi. These results suggest that CsA exhibits antifibrotic effects by degrading HIF-1α and that the CsA-HIF-1α axis provides new insights into therapeutic options for the treatment of IPF.-Yamazaki, R., Kasuya, Y., Fujita, T., Umezawa, H., Yanagihara, M., Nakamura, H., Yoshino, I., Tatsumi, K., Murayama, T. Antifibrotic effects of cyclosporine A on TGF-ß1-treated lung fibroblasts and lungs from bleomycin-treated mice: role of hypoxia-inducible factor-1α.

Stress-Activated Protein Kinases in Spinal Cord Injury: Focus on Roles of p38.

Spinal cord injury (SCI) consists of three phases-acute, secondary, and chronic damages-and limiting the development of secondary damage possibly improves functional recovery after SCI. A major component of the secondary phase of SCI is regarded as inflammation-triggered events: induction of cytokines, edema, microglial activation, apoptosis of cells including oligodendrocytes and neurons, demyelination, formation of the astrocytic scar, and so on. Two major stress-activated protein kinases (SAPKs)-c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK)-are activated in various types of cells in response to cellular stresses such as apoptotic stimuli and inflammatory waves. In animal models of SCI, inhibition of either JNK or p38 has been shown to promote neuroprotection-associated functional recovery. Here, we provide an overview on the roles of SAPKs in SCI and, in particular, the pathological role of p38 will be discussed as a promising target for therapeutic intervention in SCI.

Severe Hypomyelination and Developmental Defects Are Caused in Mice Lacking Protein Arginine Methyltransferase 1 (PRMT1) in the Central Nervous System.

Protein arginine methyltransferase 1 (PRMT1) is involved in cell proliferation, DNA damage response, and transcriptional regulation. Although PRMT1 is extensively expressed in the CNS at embryonic and perinatal stages, the physiological role of PRMT1 has been poorly understood. Here, to investigate the primary function of PRMT1 in the CNS, we generated CNS-specific PRMT1 knock-out mice by the Cre-loxP system. These mice exhibited postnatal growth retardation with tremors, and most of them died within 2 weeks after birth. Brain histological analyses revealed prominent cell reduction in the white matter tracts of the mutant mice. Furthermore, ultrastructural analysis demonstrated that myelin sheath was almost completely ablated in the CNS of these animals. In agreement with hypomyelination, we also observed that most major myelin proteins including myelin basic protein (MBP), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase), and myelin-associated glycoprotein (MAG) were dramatically decreased, although neuronal and astrocytic markers were preserved in the brain of CNS-specific PRMT1 knock-out mice. These animals had a reduced number of OLIG2(+) oligodendrocyte lineage cells in the white matter. We found that expressions of transcription factors essential for oligodendrocyte specification and further maturation were significantly suppressed in the brain of the mutant mice. Our findings provide evidence that PRMT1 is required for CNS development, especially for oligodendrocyte maturation processes.

Arginine methylation of FOXO transcription factors inhibits their phosphorylation by Akt.

Forkhead box O (FOXO) transcription factors, the key regulators of cell survival, are negatively controlled through the PI3K-Akt signaling pathway. Phosphorylation of FOXO by Akt leads to cytoplasmic localization and subsequent degradation via the ubiquitin-proteasome system. Here we show a paradigm of FOXO1 regulation by the protein arginine methyltransferase PRMT1. PRMT1 methylated FOXO1 at conserved Arg248 and Arg250 within a consensus motif for Akt phosphorylation; this methylation directly blocked Akt-mediated phosphorylation of FOXO1 at Ser253 in vitro and in vivo. Silencing of PRMT1 by small interfering RNA enhanced nuclear exclusion, polyubiquitination, and proteasomal degradation of FOXO1. PRMT1 knockdown led to a decrease in oxidative-stress-induced apoptosis depending on the PI3K-Akt signaling pathway. Furthermore, stable expression of enzymatic inactive PRMT1 mutant increased resistance to apoptosis, whereas this effect was reversed by expression of phosphorylation-deficient FOXO1. Our findings predict a role for arginine methylation as an inhibitory modification against Akt-mediated phosphorylation.

Bidirectional role of IL-6 signal in pathogenesis of lung fibrosis.

BACKGROUND: Various signals are known to participate in the pathogenesis of lung fibrosis. Our aim was to determine which signal is predominantly mobilized in the early inflammatory phase and thereafter modulates the development of lung fibrosis. METHODS: Mice received a single dose of 3 mg/kg body weight of bleomycin (BLM) and were sacrificed at designated days post-instillation (dpi). Lung homogenates and sections from mice in the early inflammatory phase were subjected to phospho-protein array analysis and immunofluorescence studies, respectively. Bronchoalveolar lavage fluid (BALF) from mice was subjected to an enzyme-linked immunosorbent assay (EIA) for interleukin (IL)-6 and evaluation of infiltrated cell populations. The effects of endogenous and exogenous IL-6 on the BLM-induced apoptotic signal in A549 cells and type 2 pneumocytes were elucidated. In addition, the effect of IL-6-neutralizing antibody on BLM-induced lung injury was evaluated. RESULTS: Phospho-protein array revealed that BLM induced phosphorylation of molecules downstream of the IL-6 receptor such as Stat3 and Akt in the lung at 3 dpi. At 3 dpi, immunofluorescence studies showed that signals of phospho-Stat3 and -Akt were localized in type 2 pneumocytes, and that BLM-induced IL-6-like immunoreactivity was predominantly observed in type 2 pneumocytes. Activation of caspases in BLM-treated A549 cells and type 2 pneumocytes was augmented by application of IL-6-neutralizing antibody, a PI3K inhibitor or a Stat3 inhibitor. EIA revealed that BLM-induced IL-6 in BALF was biphasic, with the first increase from 0.5 to 3 dpi followed by the second increase from 8 to 10 dpi. Blockade of the first increase of IL-6 by IL-6-neutralizing antibody enhanced apoptosis of type 2 pneumocytes and neutrophilic infiltration and markedly accelerated fibrosis in the lung. In contrast, blockade of the second increase of IL-6 by IL-6-neutralizing antibody ameliorated lung fibrosis. CONCLUSIONS: The present study demonstrated that IL-6 could play a bidirectional role in the pathogenesis of lung fibrosis. In particular, upregulation of IL-6 at the early inflammatory stage of BLM-injured lung has antifibrotic activity through regulating the cell fate of type 2 pneumocytes in an autocrine/paracrine manner.

Therapeutic effect of lung mixed culture-derived epithelial cells on lung fibrosis.

Cell-based therapy is recognized as one of potential therapeutic options for lung fibrosis. However, preparing stem/progenitor cells is complicated and not always efficient. Here, we show easily prepared cell populations having therapeutic capacity for lung inflammatory disease that are named as 'lung mixed culture-derived epithelial cells' (LMDECs). LMDECs expressed surfactant protein (SP)-C and gave rise to type I alveolar epithelial cells (AECs) in vitro and in vivo that partly satisfied type II AEC-like characteristics. An intratracheal delivery of not HEK 293 cells but LMDECs to the lung ameliorated bleomycin (BLM)-induced lung injury. A comprehensive analysis of bronchoalveolar fluid by western blot array revealed that LMDEC engraftment could improve the microenvironment in the BLM-instilled lung in association with stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 signaling axis. SDF-1 enhanced both migration activity and differentiating efficiency of LMDECs. Further classification of LMDECs by flow cytometric study showed that a major population of LMDECs (LMDEC(Maj), 84% of total LMDECs) was simultaneously SP-C(+), CD44(+), CD45(+), and hematopoietic cell lineage(+) and that LMDECs included bronchioalveolar stem cells (BASCs) showing SP-C(+)Clara cell secretory protein(+)stem cell antigen (Sca)1(+) as a small population (1.8% of total LMDECs). CD44(+)-sorted LMDEC(Maj) and Sca1(+)-sorted LMDECs equally ameliorated fibrosis induced by BLM like LMDECs did. However, infiltrated neutrophils were observed in Sca1(+)-sorted LMDEC-treated alveoli that was not typical in LMDEC(Maj)- or LMDEC-treated alveoli. These findings suggest that the protective effect of LMDECs against BLM-induced lung injury depends greatly on that of LMDEC(Maj). Furthermore, the cells expressing both alveolar epithelial and hematopoietic cell lineage markers (SP-C(+)CD45(+)) that have characteristics corresponding to LMDEC(Maj) were observed in the alveoli of lung and increased approximately threefold in response to BLM instillation. Taken together, LMDECs newly classified in the present study are easily culture expanded and have a potential role in future regenerative cell therapy for pulmonary fibrosis.

p38 Mitogen-activated protein kinase accelerates emphysema in mouse model of chronic obstructive pulmonary disease.

CONTEXT: There are few short-term mouse models of chronic obstructive pulmonary disease (COPD) mimicking the human disease. In addition, p38 is recently recognized as a target for the treatment of COPD. However, the precise mechanism how p38 contributes to the pathogenesis of COPD is still unknown. OBJECTIVE: We attempted to create a new mouse model for COPD by intra-tracheal administration of a mixture of lipopolysaccharide (LPS) and cigarette smoke solution (CSS), and investigated the importance of the p38 mitogen-activated protein kinase (p38) pathway in the pathogenesis of COPD. METHODS: Mice were administered LPS + CSS once a day on days 0-4 and 7-11. Thereafter, CSS alone was administered to mice once a day on days 14-18. On day 28, histopathological changes of the lung were evaluated, and bronchoalveolar lavage fluid (BALF) was subjected to western blot array for cytokines. Transgenic (TG) mice expressing a constitutive-active form of MKK6, a p38-specific activator in the lung, were subjected to our experimental protocol of COPD model. RESULTS: LPS + CSS administration induced enlargement of alveolar air spaces and destruction of lung parenchyma. BALF analyses of the LPS + CSS group revealed an increase in expression levels of several cytokines involved in the pathogenesis of human COPD. These results suggest that our experimental protocol can induce COPD in mice. Likewise, histopathological findings of the lung and induction of cytokines in BALF from MKK6 c.a.-TG mice were more marked than those in WT mice. CONCLUSION: In a new experimental COPD mouse model, p38 accelerates the development of emphysema.

Eliglustat exerts anti-fibrotic effects by activating SREBP2 in TGF-ß1-treated myofibroblasts derived from patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic lung disease. Myofibroblasts play a critical role in fibrosis. These cells produce the extracellular matrix (ECM), which contributes to tissue regeneration; however, excess ECM production can cause fibrosis. Transforming growth factor-ß (TGF-ß)/Smad signaling induces ECM production by myofibroblasts; therefore, the inhibition of TGF-ß/Smad signaling may be an effective strategy for IPF treatment. We recently reported that miglustat, an inhibitor of glucosylceramide synthase (GCS), ameliorates pulmonary fibrosis by inhibiting the nuclear translocation of Smad2/3. In the present study, we examined the anti-fibrotic effects of another GCS inhibitor, eliglustat, a clinically approved drug for treating Gaucher disease type 1, in myofibroblasts derived from patient with IPF (IPF-MyoFs). We found that eliglustat exerted anti-fibrotic effects independent of GCS inhibition, and inhibited TGF-ß1-induced expression of α-smooth muscle actin, a marker of fibrosis, without suppressing the phosphorylation and nuclear translocation of Smad2/3. RNA sequencing analysis of eliglustat-treated human lung fibroblasts identified sterol regulatory element-binding protein 2 (SREBP2) activation. Transient overexpression of SREBP2 attenuated the TGF-ß1-induced increase in the expression of Smad target genes in IPF-MyoFs, and SREBP2 knockdown nullified the inhibitory effect of eliglustat on TGF-ß1-induced expression of α-SMA. These results suggested that eliglustat exerts its anti-fibrotic effects through SREBP2 activation. The findings of this study may contribute to the development of novel therapeutic strategies for IPF treatment.

Mechanism for p38α-mediated experimental autoimmune encephalomyelitis.

One of the mitogen-activated protein kinases, p38, has been found to play a crucial role in various inflammatory responses. In this study, we analyzed the roles of p38α in multiple sclerosis, using an animal model, experimental autoimmune encephalomyelitis (EAE). p38α(+/-) mice (p38α(-/-) showed embryonic lethality) showed less severe neurological signs than WT mice. Adoptive transfer of lymph node cells (LNC) from sensitized WT mice with MOG(35-55) to naive WT-induced EAE was much more severe compared with the case using LNC from sensitized p38α(+/-) mice. Comprehensive analysis of cytokines from MOG(35-55)-challenged LNC by Western blot array revealed that production of IL-17 was significantly reduced by a single copy disruption of the p38α gene or a p38 inhibitor. Likewise, by a luciferase reporter assay, an electrophoresis mobility shift assay, and characterization of the relationship between p38 activity and IL-17 mRNA expression, we confirmed that p38 positively regulates transcription of the Il17 gene. Furthermore, oral administration of a highly specific p38α inhibitor (UR-5269) to WT mice at the onset of EAE markedly suppressed the progression of EAE compared with a vehicle group. These results suggest that p38α participates in the pathogenesis of EAE through IL-17 induction.

Functional roles of CD26/DPP4 in bleomycin-induced pulmonary fibrosis.

The pathogenesis of pulmonary fibrosis involves complex interplay between cell types and signaling pathways. Recurrent alveolar epithelial injury can occur during pulmonary inflammation, causing dysregulation of epithelial repair. Dysregulated repair interacts with mesenchymal, inflammatory, and endothelial cells to trigger fibroblast-to-myofibroblast activation. CD26/dipeptidyl peptidase-4 (DPP4) is a type II membrane protein mediating pleiotropic effect. However, the mechanistic role of CD26/DPP4 in pulmonary fibrosis remains unclear. In this study, we aimed to characterize Dpp4 deficiency in a mouse bleomycin (BLM)-induced pulmonary fibrosis model and in cell culture systems of human lung fibroblasts (HLFs). Dpp4 knockout (Dpp4 KO) mouse lungs exhibited lower Ashcroft scale indices, collagen content, and numbers of fibroblasts and myofibroblasts compared with those in C57BL/6 wild-type (WT) mice. Upregulation of Tgfb1 and Tgfb2 mRNA levels in the lungs after BLM treatment was lower in Dpp4 KO mice compared with those in WT mice. Although TGF-ß-driven endothelial-to-mesenchymal transition (EndMT) has been implicated as one of the mechanisms of pulmonary fibrosis, a number of partial EndMT cells in lungs did not differ between Dpp4 KO mice and WT mice. The proliferation capacity and mRNA levels of COL1A1, a collagen deposition-related gene, in cultured HLFs were suppressed in DPP4 small interfering RNA-treated cells. This study indicates that the genetic deficiency of DPP4 has protective effects against BLM-induced pulmonary fibrosis, partly through the reduction in TGF-ß expression and inhibition of fibroblast activation in the lung. Our study suggests that CD26/DPP4 inhibition is a potential therapeutic strategy for pulmonary fibrosis.

N-butyldeoxynojirimycin (miglustat) ameliorates pulmonary fibrosis through inhibition of nuclear translocation of Smad2/3.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease. The disease involves excessive accumulation of fibroblasts and myofibroblasts, and myofibroblasts differentiated by pro-fibrotic factors promote the deposition of extracellular matrix proteins such as collagen and fibronectin. Transforming growth factor-ß1 is a pro-fibrotic factor that promotes fibroblast-to-myofibroblast differentiation (FMD). Therefore, inhibition of FMD may be an effective strategy for IPF treatment. In this study, we screened the anti-FMD effects of various iminosugars and showed that some compounds, including N-butyldeoxynojirimycin (NB-DNJ, miglustat, an inhibitor of glucosylceramide synthase (GCS)), a clinically approved drug for treating Niemann-Pick disease type C and Gaucher disease type 1, inhibited TGF-ß1-induced FMD by inhibiting the nuclear translocation of Smad2/3. N-butyldeoxygalactonojirimycin having GCS inhibitory effect did not attenuate the TGF-ß1-induced FMD, suggesting that NB-DNJ exerts the anti-FMD effects by GCS inhibitory effect independent manner. N-butyldeoxynojirimycin did not inhibit TGF-ß1-induced Smad2/3 phosphorylation. In a mouse model of bleomycin (BLM)-induced pulmonary fibrosis, intratracheal or oral administration of NB-DNJ at an early fibrotic stage markedly ameliorated lung injury and deterioration of respiratory functions, such as specific airway resistance, tidal volume, and peak expiratory flow. Furthermore, the anti-fibrotic effects of NB-DNJ in the BLM-induced lung injury model were similar to those of pirfenidone and nintedanib, which are clinically approved drugs for the treatment of IPF. These results suggest that NB-DNJ may be effective for IPF treatment.

Regulation of neural stem cell proliferation and survival by protein arginine methyltransferase 1.

Protein arginine methyltransferase 1 (PRMT1), a major type I arginine methyltransferase in mammals, methylates histone and non-histone proteins to regulate various cellular functions, such as transcription, DNA damage response, and signal transduction. PRMT1 is highly expressed in neural stem cells (NSCs) and embryonic brains, suggesting that PRMT1 is essential for early brain development. Although our previous reports have shown that PRMT1 positively regulates oligodendrocyte development, it has not been studied whether PRMT1 regulates NSC proliferation and its survival during development. To examine the role of PRMT1 in NSC activity, we cultured NSCs prepared from embryonic mouse forebrains deficient in PRMT1 specific for NSCs and performed neurosphere assays. We found that the primary neurospheres of PRMT1-deficient NSCs were small and the number of spheres was decreased, compared to those of control NSCs. Primary neurospheres deficient in PRMT1 expressed an increased level of cleaved caspase-3, suggesting that PRMT1 deficiency-induced apoptosis. Furthermore, p53 protein was significantly accumulated in PRMT1-deficient NSCs. In parallel, p53-responsive pro-apoptotic genes including Pmaip1 and Perp were upregulated in PRMT1-deficient NSCs. p53-target p21 mRNA and its protein levels were shown to be upregulated in PRMT1-deficient NSCs. Moreover, the 5-bromo-2'-deoxyuridine (BrdU) incorporation assay showed that the loss of PRMT1 led to cell cycle defects in the embryonic NSCs. In contrast to the above in vitro observations, NSCs normally proliferated and survived in the fetal brains of NSC-specific PRMT1-deficient mice. We also found that Lama1, which encodes the laminin subunit α1, was significantly upregulated in the embryonic brains of PRMT1-deficient mice. These data implicate that extracellular factors provided by neighboring cells in the microenvironment gave a trophic support to NSCs in the PRMT1-deficient brain and recovered NSC activity to maintain brain homeostasis. Our study implies that PRMT1 plays a cell-autonomous role in the survival and proliferation of embryonic NSCs.

Multi­omics analysis of right ventricles in rat models of pulmonary arterial hypertension: Consideration of mitochondrial biogenesis by chrysin.

In pulmonary arterial hypertension (PAH), right ventricular failure is accompanied by metabolic alterations in cardiomyocytes, which may be due to mitochondrial dysfunction and decreased energy production. Chrysin (CH) is a phytochemical with pharmacological activity that is involved in the regulation of mitochondrial biogenesis. The present study investigated the role of CH in the right ventricle (RV) by analyzing the cardiac transcriptome and metabolome of a SU5416(a vascular endothelial growth factor receptor blocker, /hypoxia (Su/Hx) rat model of PAH. RNA­sequencing of the RV transcriptome between Su/Hx, Su/Hx with CH (Su/Hx + CH) and control groups, extracellular matrix (ECM) organization and ECM­receptor interaction­associated genes were upregulated in the RV of Su/Hx but not Su/Hx + CH rats. Furthermore, expression of mitochondrial function­, energy production­, oxidative phosphorylation­ and tricarboxylic acid (TCA) cycle­associated genes was decreased in the RV of Su/Hx rats; this was reverse by CH. Metabolomic profiling analysis of Su/Hx and Su/Hx + CH rats showed no significant changes in glycolysis, TCA cycle, glutathione, NADH or NADPH. By contrast, in the RV of Su/Hx rats, decreased adenylate energy charge was partially reversed by CH administration, suggesting that CH was involved in the improvement of mitochondrial biogenesis. Reverse transcription­quantitative PCR analysis revealed that expression of peroxisome proliferator­activated receptor γ, a master regulator of fatty acid metabolism and mitochondrial biogenesis, was increased in the RV of Su/Hx + CH rats. CH ameliorated cardiac abnormality, including cardiac fibrosis, RV hypertrophy and PH. The present study suggested that CH altered patterns of gene expression and levels of mitochondrial metabolites in cardiomyocytes, thus improving RV dysfunction in a Su/Hx PAH rat model.

N-type calcium channel in the pathogenesis of experimental autoimmune encephalomyelitis.

One of the family of voltage-gated calcium channels (VGCC), the N-type Ca(2+) channel, is located predominantly in neurons and is associated with a variety of neuronal responses, including neurodegeneration. A precise mechanism for how the N-type Ca(2+) channel plays a role in neurodegenerative disease, however, is unknown. In this study, we immunized N-type Ca(2+) channel α(1B)-deficient (α(1B)(-/-)) mice and their wild type (WT) littermates with myelin oligodendrocyte glycoprotein 35-55 and analyzed the progression of experimental autoimmune encephalomyelitis (EAE). The neurological symptoms of EAE in the α(1B)(-/-) mice were less severe than in the WT mice. In conjunction with these results, sections of the spinal cord (SC) from α(1B)(-/-) mice revealed a reduction in both leukocytic infiltration and demyelination compared with WT mice. No differences were observed in the delayed-type hypersensitivity response, spleen cell proliferation, or cytokine production from splenocytes between the two genotypes. On the other hand, Western blot array analysis and RT-PCR revealed that a typical increase in the expression of MCP-1 in the SC showed a good correlation with the infiltration of leukocytes into the SC. Likewise, immunohistochemical analysis showed that the predominant source of MCP-1 was activated microglia. The cytokine-induced production of MCP-1 in primary cultured microglia from WT mice was significantly higher than that from α(1B)(-/-) mice and was significantly inhibited by a selective N-type Ca(2+) channel antagonist, ω-conotoxin GVIA or a withdrawal of extracellular Ca(2+). These results suggest that the N-type Ca(2+) channel is involved in the pathogenesis of EAE at least in part by regulating MCP-1 production by microglia.

Functional analysis of guinea pig ß1-adrenoceptor.

Although similarity of pharmacological responses to certain stimuli between guinea pigs and humans has been reported, this has been poorly defined by a molecular biological approach. In this study, we cloned the gene of guinea pig ?1-adrenoceptor (ADRB1). The deduced amino acid sequence of guinea pig ADRB1 (467-aa) showed 91% and 92% identity with the human and rat ADRB1 sequences, respectively. Using HEK293T cells expressing guinea pig, human and rat ADRB1s independently, we elucidated the functional characteristics of each ADRB1. The ligand-binding profiles and the concentration-response relationships for isoprenaline-induced cyclic adenosine monophosphate (cAMP) production were similar among the three ADRB1s. Isoprenaline also induced phosphorylation of extracellular-signal related kinases (ERK) through ADRB1s in a concentration-dependent manner. The minimum effective concentration of isoprenaline for phosphorylation of ERK, through guinea pig ADRB1 was the same as through human ADRB1, but markedly lower than that of through rat ADRB1. ERK phosphorylation through guinea pig ADRB1 was sensitive to pertussis toxin, a dominant-negative ras and PD98059, indicating that a G(i)-mediated pathway is involved in the ADRB1/ERK signaling loop. These results suggest that the G(i)-coupling efficacy of guinea pig and human ADRB1s may be higher than that of rat ADRB1.

Cigarette smoke-induced pulmonary inflammation is attenuated in CD69-deficient mice.

Cluster of differentiation 69 (CD69) has been identified as a lymphocyte early activation marker, and recent studies have indicated that CD69 mediates intracellular signals and plays an important role in various inflammatory diseases. Cigarette smoke (CS) is a strong proinflammatory stimulus that induces the release of proinflammatory mediators by recruiting macrophages and neutrophils into the lung tissue, and is one of the main risk factors for a number of chronic diseases. However, the potential role of CD69 in CS-induced pulmonary inflammation has not been determined. To address to this question, CD69-deficient (KO) and wild-type (WT) mice were subjected to CS-induced acute pulmonary inflammation. After the exposure with CS, the expression of CD69 in the lung of WT mice was significantly induced, it was predominantly observed in macrophages. In conjunction with this phenomenon, neutrophil and macrophage cell counts, and expression of several cytokines were significantly higher in the bronchoalveolar lavage fluid (BALF) of CS-exposed WT mice compared with air-exposed WT mice. Likewise, the CS-induced accumulation of inflammatory cells and cytokines expression were significantly lower in CD69-KO mice than in WT mice. These results suggest that CD69 on macrophages is involved in CS-induced acute pulmonary inflammation.

Attenuation of lung inflammation and fibrosis in CD69-deficient mice after intratracheal bleomycin.

BACKGROUND: Cluster of differentiation 69 (CD69), an early activation marker antigen on T and B cells, is also expressed on activated macrophages and neutrophils, suggesting that CD69 may play a role in inflammatory diseases. To determine the effect of CD69 deficiency on bleomycin(BLM)-induced lung injury, we evaluated the inflammatory response following intratracheal BLM administration and the subsequent fibrotic changes in wild type (WT) and CD69-deficient (CD69-/-) mice. METHODS: The mice received a single dose of 3 mg/kg body weight of BLM and were sacrificed at 7 or 14 days post-instillation (dpi). Lung inflammation in the acute phase (7 dpi) was investigated by differential cell counts and cytokine array analyses of bronchoalveolar lavage fluid. In addition, lung fibrotic changes were evaluated at 14 dpi by histopathology and collagen assays. We also used reverse transcription polymerase chain reaction to measure the mRNA expression level of transforming growth factor ß1 (TGF-ß1) in the lungs of BLM-treated mice. RESULTS: CD69-/- mice exhibited less lung damage than WT mice, as shown by reductions in the following indices: (1) loss of body weight, (2) wet/dry ratio of lung, (3) cytokine levels in BALF, (4) histological evidence of lung injury, (5) lung collagen deposition, and (6) TGF-ß1 mRNA expression in the lung. CONCLUSION: The present study clearly demonstrates that CD69 plays an important role in the progression of lung injury induced by BLM.