Pharmacological Activation of TRPC6 Channel Prevents Colitis Progression

We recently reported that transient receptor potential canonical (TRPC) 6 channel activity contributes to intracellular Zn2+ homeostasis in the heart. Zn2+ has also been implicated in the regulation of intestinal redox and microbial homeostasis. This study aims to investigate the role of TRPC6-mediated Zn2+ influx in the stress resistance of the intestine. The expression profile of TRPC1-C7 mRNAs in the actively inflamed mucosa from inflammatory bowel disease (IBD) patients was analyzed using the GEO database. Systemic TRPC3 knockout (KO) and TRPC6 KO mice were treated with dextran sulfate sodium (DSS) to induce colitis. The Zn2+ concentration and the mRNA expression levels of oxidative/inflammatory markers in colon tissues were quantitatively analyzed, and gut microbiota profiles were compared. TRPC6 mRNA expression level was increased in IBD patients and DSS-treated mouse colon tissues. DSS-treated TRPC6 KO mice, but not TRPC3 KO mice, showed severe weight loss and increased disease activity index compared with DSS-treated WT mice. The mRNA abundances of antioxidant proteins were basically increased in the TRPC6 KO colon, with changes in gut microbiota profiles. Treatment with TRPC6 activator prevented the DSS-induced colitis progression accompanied by increasing Zn2+ concentration. We suggest that TRPC6-mediated Zn2+ influx activity plays a key role in stress resistance against IBD, providing a new strategy for treating colitis.

Functional role of IL-19 in a mouse model of L-arginine-induced pancreatitis and related lung injury

IL-19 is a member of IL-10 family and is mainly produced by macrophages. Acute pancreatitis (AP) is an inflammatory disease characterized by acinar cell injury and necrosis. In the present study, the role of IL-19 in AP and AP-associated lung injury in mice was explored using L-arginine-induced pancreatitis. Experimental pancreatitis was induced by intraperitoneal injection of L-arginine in wild-type (WT) and IL-19 gene deficient (IL-19 KO) mice. In L-arginine treated mice, the serum amylase level was significantly increased in IL-19 KO mice, and interstitial edema, analyzed using hematoxylin and eosin (H&E)-stained sections, was aggravated mildly in IL-19 KO mice compared to WT mice. Compared to WT mice treated with L-arginine, mRNA expression of tumor necrosis factor (TNF)-α was significantly upregulated in IL-19 KO mice treated with L-arginine. In WT mice, IL-19 mRNA was equally expressed in the pancreas of both control and L-arginine treated mice. The condition of lung alveoli in WT and IL-19 KO mice treated with L-arginine was then evaluated. In mice with L-arginine-induced pancreatitis, alveolar area was remarkedly decreased, and expression of lung myeloperoxidase was significantly increased in IL-19 KO mice compared to WT mice. In the lungs, mRNA expressions of IL-6 and inducible nitric oxide synthase were significantly increased in IL-19 KO mice compared to WT mice. In summary, IL-19 was proposed to alleviate L-arginine-induced pancreatitis by regulating TNF-α production and to protect against AP-related lung injury by inhibiting neutrophil migration.

Interleukin-19 Gene-Deficient Mice Promote Liver Fibrosis via Enhanced TGF-β Signaling, and the Interleukin-19-CCL2 Axis Is Important in the Direction of Liver Fibrosis

IL-19 is a cytokine discovered by homologous searching with IL-10 and is produced by non-immune cells, such as keratinocytes, in addition to immune cells, such as macrophages. Liver fibrosis results from the inflammation and activation of hepatic stellate cells via chronic liver injury. However, the participation of IL-19 in liver fibrosis remains to be sufficiently elucidated. Our group studied the immunological function of IL-19 in a mouse model of carbon tetrachloride (CCl₄)-induced liver fibrosis. IL-19 gene-deficient (KO) mice and body weight-matched wild-type (WT) mice were used. A liver fibrosis mouse model was created via CCl₄ administration (two times per week) for 8 weeks. In CCl₄-induced liver fibrosis, serum analysis revealed that IL-19 KO mice had higher ALT levels compared to WT mice. IL-19 KO mice had worse fibrosis, as assessed by morphological evaluation of total area stained positive with Azan and Masson trichrome. In addition, the expression of α-SMA was increased in liver tissues of IL-19 KO mice compared to WT mice. Furthermore, mRNA expression levels of TGF-β and α-SMA were enhanced in IL-19 KO mice compared to WT mice. In vitro assays revealed that IL-19-high expressing RAW264.7 cells inhibited the migration of NIH3T3 cells via the inhibited expression of CCL2 in the presence of CCl₄ and IL-4. These findings indicate that IL-19 plays a critical role in liver fibrosis by affecting TGF-β signaling and the migration of hepatic stellate cells during liver injury. Enhancement of the IL-19 signaling pathway is a potential treatment for liver fibrosis.

Stress decreases contraction of the colon, and the effects of stress are different among the regions of the colon

Stress affects a variety of organs. Diarrhea and constipation are closely related to stress, which involves the gastrointestinal motility of the colon. We compared the gastrointestinal motility of the proximal, mid, and distal colon in mice with stress. Stress was applied by water immersion restraint. Colon motility was measured using an isotonic transducer in the direction of the circular muscles. Electric field stimulation-induced contractions in stressed mice were reduced compared to control mice in the proximal and distal colon. On the other hand, in the mid colon, contraction in control mice and stressed mice were almost same. This interesting difference between the regions may provide a clue to the functional abnormalities in gastrointestinal motility associated with stress.

Redox-dependent internalization of the purinergic P2Y6 receptor limits colitis progression

[Figure: see text].

[Recent topics on interorgan communication networks and gut microbiota]

The living body is composed of diverse organ systems, each of which has its own characteristic control mechanisms and complex in vivo responses. Between the brain and organs such as the heart, kidney, liver, pancreas, gastrointestinal tract, and even muscles, there is a sophisticated and complex regulatory system. Coordinated interactions through communication between organs are essential for maintaining health. In this review, we introduce four research trends in inter-organ networks, with a focus on the digestive system: 1) Inter-organ networks on metabolic systems, 2) Inter-organ networks originating from the gastrointestinal tract, 3) Intestinal bacteria, that is one of the biggest topics in recent years, 4) Research results on the involvement of gut microbiota in the inter-organ network between the kidney and the gastrointestinal tract. An integrated understanding and investigation of the regulatory mechanisms of inter-organ communication networks are expected to extend healthy life span and improve quality of life.

Ablation of interleukin-19 improves motor function in a mouse model of amyotrophic lateral sclerosis

Neuroinflammation by activated microglia and astrocytes plays a critical role in progression of amyotrophic lateral sclerosis (ALS). Interleukin-19 (IL-19) is a negative-feedback regulator that limits pro-inflammatory responses of microglia in an autocrine and paracrine manner, but it remains unclear how IL-19 contributes to ALS pathogenesis. We investigated the role of IL-19 in ALS using transgenic mice carrying human superoxide dismutase 1 with the G93A mutation (SOD1G93A Tg mice). We generated IL-19-deficient SOD1G93A Tg (IL-19-/-/SOD1G93A Tg) mice by crossing SOD1G93A Tg mice with IL-19-/- mice, and then evaluated disease progression, motor function, survival rate, and pathological and biochemical alternations in the resultant mice. In addition, we assessed the effect of IL-19 on glial cells using primary microglia and astrocyte cultures from the embryonic brains of SOD1G93A Tg mice and IL-19-/-/SOD1G93A Tg mice. Expression of IL-19 in primary microglia and lumbar spinal cord was higher in SOD1G93A Tg mice than in wild-type mice. Unexpectedly, IL-19-/-/SOD1G93A Tg mice exhibited significant improvement of motor function. Ablation of IL-19 in SOD1G93A Tg mice increased expression of both neurotoxic and neuroprotective factors, including tumor necrosis factor-α (TNF-α), IL-1β, glial cell line-derived neurotrophic factor (GDNF), and transforming growth factor β1, in lumbar spinal cord. Primary microglia and astrocytes from IL-19-/-/SOD1G93A Tg mice expressed higher levels of TNF-α, resulting in release of GDNF from astrocytes. Inhibition of IL-19 signaling may alleviate ALS symptoms.

Interleukin-19 Abrogates Experimental Autoimmune Encephalomyelitis by Attenuating Antigen-Presenting Cell Activation

Interleukin-19 (IL-19) acts as a negative-feedback regulator to limit proinflammatory response of macrophages and microglia in autocrine/paracrine manners in various inflammatory diseases. Multiple sclerosis (MS) is a major neuroinflammatory disease in the central nervous system (CNS), but it remains uncertain how IL-19 contributes to MS pathogenesis. Here, we demonstrate that IL-19 deficiency aggravates experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by promoting IL-17-producing helper T cell (Th17 cell) infiltration into the CNS. In addition, IL-19-deficient splenic macrophages expressed elevated levels of major histocompatibility complex (MHC) class II, co-stimulatory molecules, and Th17 cell differentiation-associated cytokines such as IL-1β, IL-6, IL-23, TGF-β1, and TNF-α. These observations indicated that IL-19 plays a critical role in suppression of MS pathogenesis by inhibiting macrophage antigen presentation, Th17 cell expansion, and subsequent inflammatory responses. Furthermore, treatment with IL-19 significantly abrogated EAE. Our data suggest that IL-19 could provide significant therapeutic benefits in patients with MS.

Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel

Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie non-selective cation currents and are downstream effectors of G protein-coupled receptors. Ca²⁺ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel.

[Therapeutic application utilizing the anti-inflammatory effect of IL-19]

Interleukin-19 (IL-19) is a member of the IL-10 family and is an anti-inflammatory cytokine produced mainly by macrophages, epithelial cells, and vascular smooth muscle cells. In addition, receptors for IL-19, IL-20 receptor 1 and IL-20 receptor 2, are also expressed in the cells mentioned above. The last 10 years from the finding of IL-19, investigations underline the anti-inflammatory role of IL-19 in the human diseases such as psoriasis, asthma, arteriosclerosis, and inflammatory bowel disease. If it is a pro-inflammatory cytokine, therapeutic applications may include the use of neutralizing antibodies, however, because IL-19 exhibits anti-inflammatory effects, recombinant products may be useful in therapeutic applications. However, the therapeutic applications of IL-19 for human disease have not yet been developed. In this review, we present the new findings on the preventive and therapeutic effects of IL-19 on various mouse disease models. Increasing knowledge about mouse disease models will increase the feasibility of future human disease applications.

Interleukin-19 as an Immunoregulatory Cytokine

IL-19 is a type of anti-inflammatory cytokine. Since the receptor for IL-19 is common to IL-20 and IL-24, it is important to clarify the role of each of the three cytokines. If three different cytokines bind to the same receptor, these three may have been produced to complement the other two. However, perhaps it is unlikely. Recently, the existence of a novel receptor for IL-19 was suggested. The distinction between the roles of the three cytokines still makes sense. On the other hand, because T cells do not produce IL-19, their role in acquired immunity is limited or indirect. It has been reported that IL-19 causes inflammation in some diseases but does not have an anti-inflammatory effect. In this review, we introduce the current role of IL-19 in each disease. In addition, we will describe the molecular mechanism of IL-19 and its development for the prevention of diseases. IL-19 was previously considered an anti-inflammatory cytokine, but we would like to propose it as an immunoregulatory cytokine.

Breakthroughs in Medicinal Chemistry: New Targets and Mechanisms, New Drugs, New Hopes-7

Breakthroughs in Medicinal Chemistry [...].

Interleukin-19 enhances cytokine production induced by lipopolysaccharide and inhibits cytokine production induced by polyI:C in BALB/c mice

Interleukin (IL)-19 is a cytokine of the IL-10 family. There are many reports on the involvement of IL-19 in several human diseases. There also are many reports elucidating the role of IL-19 using mouse disease models. Most reports use C57BL/6 mice, whereas few reports use BALB/c mice, in terms of the mouse disease model that the researchers used in the present study. To date, research on the role of IL-19 is diversified, yet some basic mechanisms are still unclear. In this study, we administered lipopolysaccharide (LPS), polyI:C, and CpG to BALB/c mice, measured more than 20 cytokines in the blood and compared them with that of the wild-type and IL-19-deficient (IL-19 KO) mice. LPS is associated with bacterial infection, polyI:C is associated with viral infection, and CpG is associated with both bacterial and viral infections. Among the cytokines measured, the results of experiments using LPS revealed that the production of some cytokines was suppressed in IL-19 KO mice. Interestingly, the experiments using polyI:C revealed that production of some cytokines was enhanced in IL-19 KO mice. However, the experiments using CpG have shown that the production of only one cytokine was enhanced in IL-19 KO mice. These results revealed that cytokine production in the blood was regulated by IL-19, and the type of regulation was dependent on the administered stimulant.

Fucoxanthin Ameliorates Atopic Dermatitis Symptoms by Regulating Keratinocytes and Regulatory Innate Lymphoid Cells

Fucoxanthin (FX) is a xanthophyll that is contained abundantly in marine plants. The biological action of FX includes its antioxidant and anti-lipogenic activities, while the precise action of its mechanisms on skin cells has not yet been clarified. The current study examined the effect of FX in comparison with tacrolimus (TAC) on NC/Nga mice, which are an atopic dermatitis (AD) model. FX topical treatment dramatically ameliorated itching behavior over the TAC treatment, which was insufficient for improvement of AD symptoms. In Nc/Nga mice, FX or TAC applied to the skin inhibited eosinophil infiltration with decreased expression of Il-33. FX also stimulated Il-2, Il-5, Il-13, Il-10, and TGF-β expression levels, and Sca1⁺Il-10⁺TGF-β⁺ regulatory innate lymphoid cells (ILCreg) were dominantly observed in FX treated skin epidermal keratinocytes and dermal layers. This combined evidence demonstrated that FX exerts anti-inflammatory effects on keratinocytes and ameliorates AD symptoms by regulating ILCreg to normalize immune responses in an atopic dermatitis model.

Breakthroughs in Medicinal Chemistry: New Targets and Mechanisms, New Drugs, New Hopes-6

Breakthroughs in Medicinal Chemistry: New Targets and Mechanisms, New Drugs, New Hopes is a series of Editorials that is published on a biannual basis by the Editorial Board of the Medicinal Chemistry section of the journal Molecules [...].

[Recent progress in the pathophysiological role of interleukin-19]

Cytokine signal is essential for the biological function including development, maintenance of homeostasis and progression of disease. There are growing evidences that signaling via pro-inflammatory cytokines underlie a variety of immunological diseases such as psoriasis, atopic dermatitis, inflammatory bowel disease, and metabolic syndromes, in which cytokine signals are known as a potential therapeutic target of antibody drugs. In contrast, anti-inflammatory cytokines, which is represented by IL-10, largely contribute to suppression of inflammation and restoration of injured tissues. IL-19 is a member of IL-10 cytokine family, which comprises IL-20 cytokine subfamily with IL-20, IL-22, IL-24, and IL-26. IL-19 is produced by myeloid and epithelial cells with stimulation of bacterial components and cytokines. Although IL-19 has been originally recognized as a potential Th2-related cytokine, in recent researches, it has been reported that this cytokine upregulates Th17 response to reflect and promote progression of Th17-related disease including psoriasis. On the other hand, IL-19 has anti-inflammatory effects on inflammatory diseases such as infectious skin disease, inflammatory bowel disease, and cardiovascular disease. Therefore, IL-19 may exert pleiotropic effects dependent on the pathological mechanism of inflammatory diseases. In this review, we summarize recent studies about IL-19 and introduce the pathophysiological and therapeutic role of IL-19 in inflammatory diseases.

Ibudilast attenuates doxorubicin-induced cytotoxicity by suppressing formation of TRPC3 channel and NADPH oxidase 2 protein complexes

BACKGROUND AND PURPOSE

Doxorubicin is a highly effective anticancer agent but eventually induces cardiotoxicity associated with increased production of ROS. We previously reported that a pathological protein interaction between TRPC3 channels and NADPH oxidase 2 (Nox2) contributed to doxorubicin-induced cardiac atrophy in mice. Here we have investigated the effects of ibudilast, a drug already approved for clinical use and known to block doxorubicin-induced cytotoxicity, on the TRPC3-Nox2 complex. We specifically sought evidence that this drug attenuated doxorubicin-induced systemic tissue wasting in mice.

EXPERIMENTAL APPROACH

We used the RAW264.7 macrophage cell line to screen 1,271 clinically approved chemical compounds, evaluating functional interactions between TRPC3 channels and Nox2, by measuring Nox2 protein stability and ROS production, with and without exposure to doxorubicin. In male C57BL/6 mice, samples of cardiac and gastrocnemius muscle were taken and analysed with morphometric, immunohistochemical, RT-PCR and western blot methods. In the passive smoking model, cells were exposed to DMEM containing cigarette sidestream smoke.

KEY RESULTS

Ibudilast, an anti-asthmatic drug, attenuated ROS-mediated muscle toxicity induced by doxorubicin treatment or passive smoking, by inhibiting the functional interactions between TRPC3 channels and Nox2, without reducing TRPC3 channel activity.

CONCLUSIONS AND IMPLICATIONS

These results indicate a common mechanism underlying induction of systemic tissue wasting by doxorubicin. They also suggest that ibudilast could be repurposed to prevent muscle toxicity caused by anticancer drugs or passive smoking.

The clarified role of interleukin-19 in the inflammatory bowel disease and hypersensitivity: Insights from animal models and humans

The cytokine interleukin-19 (IL-19) is a member of the IL-10 family that includes IL-20, IL-22, IL-24, and IL-26. Previous studies indicated that IL-19 is produced by keratinocytes, epithelial cells, macrophages, and B-cells. Especially, the number of IL-4-producing T cells increased, whereas the number of IFN-γ-producing T cells decreased when naive T cells from healthy people were cultured in the presence of IL-19. There is an increasing body of data demonstrating that IL-19 is associated with the development of type 1 helper T cell-responses, although IL-19 was originally associated with the development of type 2 helper T cell-responses. In this review, we will attempt to discuss current knowledge about the role of IL-19 on several T cell response-mediated inflammatory diseases including inflammatory bowel disease and hypersensitivity.

Correlation between toll-like receptor 4 and nucleotide-binding oligomerization domain 2 (NOD2) and pathological severity in dogs with chronic gastrointestinal diseases

Toll-like receptor 4 (TLR4), nucleotide-binding oligomerization domain 2 (NOD2), and TNF-α play important roles in human inflammatory bowel diseases. The aim of this study was to elucidate the relationship between Toll-like receptor 4, NOD2, and TNF-α and the severity of chronic gastrointestinal diseases in dogs. We examined the expression levels of TLR4, NOD2, and TNF-α in the stomach, duodenum, ileum, colon, and rectum obtained from 21 dogs with chronic gastrointestinal disease, including inflammatory bowel disease, high-grade lymphoma, food responsive enteropathy, chronic pancreatitis, low-grade lymphoma, inflammatory colorectal polyp, and chronic colitis. Next, we demonstrated whether there is good correlation between the expression levels of TLR4, NOD2, and TNF-α and the histopathological analysis of each sample. We found that the level of TLR4 expression in the ileum of dogs with chronic gastrointestinal disease was positively associated with the histopathological severity. We also found that the level of NOD2 expression in the duodenum, stomach, and rectum was positively associated with the histopathological severity. However, there was no correlation between TNF-α expression in the 5 regions tested in this study and the histopathological severity. These findings indicate that TLR4 and NOD2 are remarkably associated with the severity of chronic gastrointestinal disease in dogs.

Chronic kidney disease after 5/6 nephrectomy disturbs the intestinal microbiota and alters intestinal motility

Organ-organ crosstalk is involved in homeostasis. Gastrointestinal symptoms are common in patients with renal failure. The aim of this study was to elucidate the relationship between gastrointestinal motility and gastrointestinal symptoms in chronic kidney disease. We performed studies in C57BL/6 mice with chronic kidney disease after 5/6 nephrectomy. Gastrointestinal motility was evaluated by assessing the ex vivo responses of ileum and distal colon strips to electrical field stimulation. Feces were collected from mice, and the composition of the gut microbiota was analyzed using 16S ribosomal RNA sequencing. Mice with chronic kidney disease after 5/6 nephrectomy showed a decreased amount of stool, and this constipation was correlated with a suppressed contraction response in ileum motility and decreased relaxation response in distal colon motility. Spermine, one of the uremic toxins, inhibited the contraction response in ileum motility, but four types of uremic toxins showed no effect on the relaxation response in distal colon motility. The 5/6 nephrectomy procedure disturbed the balance of the gut microbiota in the mice. The motility dysregulation and constipation were resolved by antibiotic treatments. The expression levels of interleukin 6, tumor necrosis factor-α, and iNOS in 5/6 nephrectomy mice were increased in the distal colon but not in the ileum. In addition, macrophage infiltration in 5/6 nephrectomy mice was increased in the distal colon but not in the ileum. We found that 5/6 nephrectomy altered gastrointestinal motility and caused constipation by changing the gut microbiota and causing colonic inflammation. These findings indicate that renal failure was remarkably associated with gastrointestinal dysregulation.

The Role of Interleukin-19 in Contact Hypersensitivity

Interleukin (IL)-19 is a member of the IL-10 family of interleukins and is an immuno-modulatory cytokine produced by the main macrophages. The gastrointestinal tissues of IL-19 knockout mice show exacerbated experimental colitis mediated by the innate immune system and T cells. There is an increasing focus on the interaction and relationship of IL-19 with the function of T cells. Contact hypersensitivity (CHS) is T cell-mediated cutaneous inflammation. Therefore, we asked whether IL-19 causes CHS. We investigated the immunological role of IL-19 in CHS induced by 1-fluoro-2,4-dinitrofluorobenzene as a hapten. IL-19 was highly expressed in skin exposed to the hapten, and ear swelling was increased in IL-19 knockout mice. The exacerbation of the CHS response in IL-19 knockout mice correlated with increased levels of IL-17 and IL-6, but no alterations were noted in the production of interferon (IFN)γ and IL-4 in the T cells of the lymph nodes. In addition to the effect on T cell response, IL-19 knockout mice increased production of inflammatory cytokines. These results show that IL-19 suppressed hapten-dependent skin inflammation in the elicitation phase of CHS.

Lauric Acid Alleviates Neuroinflammatory Responses by Activated Microglia: Involvement of the GPR40-Dependent Pathway

In several neurodegenerative diseases such as Alzheimer's disease (AD), microglia are hyperactivated and release nitric oxide (NO) and proinflammatory cytokines, resulting its neuropathology. Mounting evidence indicates that dietary supplementation with coconut oil (CNO) reduces the cognitive deficits associated with AD; however, the precise mechanism(s) underlying the beneficial effect of CNO are unknown. In the present study, we examined the effects of lauric acid (LA), a major constituent of CNO, on microglia activated experimentally by lipopolysaccharide (LPS), using primary cultured rat microglia and the mouse microglial cell line, BV-2. LA attenuated LPS-stimulated NO production and the expression of inducible NO synthase protein without affecting cell viability. In addition, LA suppressed LPS-induced reactive oxygen species and proinflammatory cytokine production, as well as phosphorylation of p38-mitogen activated protein kinase and c-Jun N-terminal kinase. LA-induced suppression of NO production was partially but significantly reversed in the presence of GW1100, an antagonist of G protein-coupled receptor (GPR) 40, which is an LA receptor on the plasma membrane. LA also decreased LPS-induced phagocytosis, which was completely reversed by co-treatment with GW1100. Moreover, LA alleviated amyloid-β-induced enhancement of phagocytosis. These results suggest that attenuation of microglial activation by LA may occur via the GPR40-dependent pathway. Such effects of LA may reduce glial activation and the subsequent neuronal damage in AD patients who consume CNO.

Interleukin-19 is cardioprotective in dominant negative cyclic adenosine monophosphate response-element binding protein-mediated heart failure in a sex-specific manner

AIM

To investigate the role of interleukin-19 (IL-19) in a murine model of female-dominant heart failure (HF).

METHODS

Expression of one copy of a phosphorylation-deficient cyclic adenosine monophosphate response-element binding protein (dnCREB) causes HF, with accelerated morbidity and mortality in female mice compared to males. We assessed expression of IL-19, its receptor isoforms IL-20R α/β, and downstream IL-19 signaling in this model of female-dominant HF. To test the hypothesis that IL-19 is cardioprotective in dnCREB-mediated HF, we generated a novel double transgenic (DTG) mouse of dnCREB and IL-19 knockout and assessed cardiac morbidity by echocardiography and survival of male and female mice.

RESULTS

IL-19 is expressed in the murine heart with decreased expression in dnCREB female compared to male mice. Further, the relative expression of the two IL-19 receptor isoforms manifests differently in the heart by sex and by disease. Male DTG mice had accelerated mortality and cardiac morbidity compared to dnCREB males, while female DTG mice showed no additional detriment, supporting the hypothesis that IL-19 is cardioprotective in this model.

CONCLUSION

Together, these data suggest IL-19 is an important cytokine mediating sex-specific cardiac (dys) function. Ongoing investigations will elucidate the mechanism(s) of sex-specific IL-19 mediated cardiac remodeling.

Aggressive Crosstalk Between Fatty Acids and Inflammation in Macrophages and Their Influence on Metabolic Homeostasis

From the immunological point of view, macrophages are required to maintain metabolic homeostasis. Recently, there has been an increased focus on the influence of macrophage phenotypes in adipose tissue on the maintenance of metabolic homeostasis in healthy conditions because dysregulated metabolic homeostasis causes metabolic syndrome. This review notes several types of inflammatory and anti-inflammatory mediators in metabolic homeostasis. M1 macrophage polarization mediates inflammation, whereas M2 macrophage polarization mediates anti-inflammation. Fatty acids and their related factors mediate both inflammatory and anti-inflammatory responses. Saturated fatty acids and polyunsaturated fatty acids mediate inflammation, whereas marine-derived n-3 fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid, mediate anti-inflammation. In this review, we discuss the current understanding of the crosstalk between fatty acids and inflammation in macrophages and their influence on metabolic homeostasis.

Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) Aggregation Causes Mitochondrial Dysfunction during Oxidative Stress-induced Cell Death

Glycolytic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional protein that also mediates cell death under oxidative stress. We reported previously that the active-site cysteine (Cys-152) of GAPDH plays an essential role in oxidative stress-induced aggregation of GAPDH associated with cell death, and a C152A-GAPDH mutant rescues nitric oxide (NO)-induced cell death by interfering with the aggregation of wild type (WT)-GAPDH. However, the detailed mechanism underlying GAPDH aggregate-induced cell death remains elusive. Here we report that NO-induced GAPDH aggregation specifically causes mitochondrial dysfunction. First, we observed a correlation between NO-induced GAPDH aggregation and mitochondrial dysfunction, when GAPDH aggregation occurred at mitochondria in SH-SY5Y cells. In isolated mitochondria, aggregates of WT-GAPDH directly induced mitochondrial swelling and depolarization, whereas mixtures containing aggregates of C152A-GAPDH reduced mitochondrial dysfunction. Additionally, treatment with cyclosporin A improved WT-GAPDH aggregate-induced swelling and depolarization. In doxycycline-inducible SH-SY5Y cells, overexpression of WT-GAPDH augmented NO-induced mitochondrial dysfunction and increased mitochondrial GAPDH aggregation, whereas induced overexpression of C152A-GAPDH significantly suppressed mitochondrial impairment. Further, NO-induced cytochrome c release into the cytosol and nuclear translocation of apoptosis-inducing factor from mitochondria were both augmented in cells overexpressing WT-GAPDH but ameliorated in C152A-GAPDH-overexpressing cells. Interestingly, GAPDH aggregates induced necrotic cell death via a permeability transition pore (PTP) opening. The expression of either WT- or C152A-GAPDH did not affect other cell death pathways associated with protein aggregation, such as proteasome inhibition, gene expression induced by endoplasmic reticulum stress, or autophagy. Collectively, these results suggest that NO-induced GAPDH aggregation specifically induces mitochondrial dysfunction via PTP opening, leading to cell death.

Extracellular poly(ADP-ribose) is a neurotrophic signal that upregulates glial cell line-derived neurotrophic factor (GDNF) levels in vitro and in vivo

Synthesis of poly(ADP-ribose) (PAR) is catalyzed by PAR polymerase-1 (PARP-1) in neurons. PARP1 plays a role in various types of brain damage in neurodegenerative disorders. In neurons, overactivation of PARP-1 during oxidative stress induces robust PAR formation, which depletes nicotinamide adenine dinucleotide levels and leads to cell death. However, the role of the newly-formed PAR in neurodegenerative disorders remains elusive. We hypothesized that the effects of PAR could occur in the extracellular space after it is leaked from damaged neurons. Here we report that extracellular PAR (EC-PAR) functions as a neuroprotective molecule by inducing the synthesis of glial cell line-derived neurotrophic factor (GDNF) in astrocytes during neuronal cell death, both in vitro and in vivo. In primary rat astrocytes, exogenous treatment with EC-PAR produced GDNF but not other neurotrophic factors. The effect was concentration-dependent and did not affect cell viability in rat C6 astrocytoma cells. Topical injection of EC-PAR into rat striatum upregulated GDNF levels in activated astrocytes and improved pathogenic rotation behavior in a unilateral 6-hydroxydopamine model of Parkinson disease in rats. These findings indicate that EC-PAR acts as a neurotrophic enhancer by upregulating GDNF levels. This effect protects the remaining neurons following oxidative stress-induced brain damage, such as that seen with Parkinson disease.

Na+/Ca2+ exchanger contributes to stool transport in mice with experimental diarrhea

The Na⁺/Ca²⁺ exchanger (NCX) is a bidirectional transporter that is controlled by membrane potential and transmembrane gradients of Na⁺ and Ca²⁺. To reveal the functional role of NCX on gastrointestinal motility, we have previously used NCX1 and NCX2 heterozygote knockout mice (HET). We found that NCX1 and NCX2 play important roles in the motility of the gastric fundus, ileum and distal colon. Therefore, we believed that NCX1 and NCX2 play an important role in transport of intestinal contents. Here, we investigated the role of NCX in a mouse model of drug-induced diarrhea. The fecal consistencies in NCX1 HET and NCX2 HET were assessed using a diarrhea induced by magnesium sulfate, 5-hydroxytryptamine (5-HT) and prostaglandin E₂ (PGE₂). NCX2 HET, but not NCX1 HET, exacerbated magnesium sulfate-induced diarrhea by increasing watery fecals. Likewise, 5-HT-induced diarrheas were exacerbated in NCX2 HET, but not NCX1 HET. However, NCX1 HET and NCX2 HET demonstrated PGE₂ induced diarrhea similar to those of wild-type mice (WT). As well as the result of the distal colon shown previously, in the proximal and transverse colons of WT, the myenteric plexus layers and the longitudinal and circular muscle layers were strongly immunoreactive to NCX1 and NCX2. In this study, we demonstrate that NCX2 has important roles in development of diarrhea.

Overexpression of Na+/Ca2+ exchanger 1 display enhanced relaxation in the gastric fundus

In gastric smooth muscles, the released Ca²⁺ activates the contractile proteins and Ca²⁺ taken up from the cytosol cause relaxation. The Na⁺/Ca²⁺ exchanger (NCX) is an antiporter membrane protein that controls Ca²⁺ influx and efflux across the membrane. However, the possible relation of NCX in gastric fundus motility is largely unknown. Here, we investigated electric field stimulation (EFS)-induced relaxations in the circular muscles of the gastric fundus in smooth muscle-specific NCX1 transgenic mice (Tg). EFS caused a bi-phasic response, transient and sustained relaxation. The sustained relaxation prolonged for an extended period after the end of the stimulus. EFS-induced transient relaxation and sustained relaxation were greater in Tg than in wild-type mice (WT). Disruption of nitric oxide component by N-nitro-l-arginine, EFS-induced transient and sustained relaxations caused still marked in Tg compared to WT. Inhibition of PACAP by antagonist, EFS-induced sustained relaxation in Tg was not seen, similar to WT. Nevertheless, transient relaxation remained more pronounced in Tg than in WT. Next, we examined responses to NO and PACAP in smooth muscles. The magnitudes of NOR-1, which generates NO, and PACAP-induced relaxations were greater in Tg than in WT. In this study, we demonstrate that NCX1 regulates gastric fundus motility.

Na(+) /Ca(2+) exchanger-heterozygote knockout mice display increased relaxation in gastric fundus and accelerated gastric transit in vivo

BACKGROUND

For the contraction and relaxation of gastric smooth muscles to occur, the intracellular Ca(2+) concentration must be increased and decreased, respectively. The Na(+) /Ca(2+) exchanger (NCX) is a plasma membrane transporter that is involved in regulating intracellular Ca(2+) concentrations.

METHODS

To determine the role of NCX in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced relaxations in the circular muscles of the gastric fundus in NCX1 and NCX2 heterozygote knockout mice (HET).

KEY RESULTS

The myenteric plexus layers and the longitudinal and circular muscle layers in the gastric fundus of wild-type mice (WT) were strongly immunoreactive to NCX1 and NCX2. EFS induced a transient relaxation that was apparent during the stimulus and a sustained relaxation that persisted after the end of the stimulus. The amplitudes of EFS-induced transient relaxation and sustained relaxation were greater in NCX1 HET and NCX2 HET than in WT. When an inhibitor of nitric oxide synthase was added following the EFS, neither NCX1 HET nor NCX2 HET exhibited transient relaxation, similar to WT. Furthermore, when a PACAP antagonist was added following the EFS, sustained relaxation in NCX1 HET and NCX2 HET was not observed, similar to WT. Next, we examined the effect of NCX heterozygous deficiency on relaxation in response to NO and PACAP in smooth muscles. The magnitude of NOR-1- and PACAP-induced relaxations in NCX1 HET and NCX2 HET was similar to that of WT.

CONCLUSIONS & INFERENCES

In this study, we demonstrate that NCX1 and NCX2 expressed in neurons regulate the motility in the gastric fundus.

Active site cysteine-null glyceraldehyde-3-phosphate dehydrogenase (GAPDH) rescues nitric oxide-induced cell death

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a homotetrameric enzyme involved in a key step of glycolysis, also has a role in mediating cell death under nitrosative stress. Our previous reports suggest that nitric oxide-induced intramolecular disulfide-bonding GAPDH aggregation, which occurs through oxidation of the active site cysteine (Cys-152), participates in a mechanism to account for nitric oxide-induced death signaling in some neurodegenerative/neuropsychiatric disorders. Here, we demonstrate a rescue strategy for nitric oxide-induced cell death accompanied by GAPDH aggregation in a mutant with a substitution of Cys-152 to alanine (C152A-GAPDH). Pre-incubation of purified wild-type GAPDH with C152A-GAPDH under exposure to nitric oxide inhibited wild-type GAPDH aggregation in a concentration-dependent manner in vitro. Several lines of structural analysis revealed that C152A-GAPDH extensively interfered with nitric oxide-induced GAPDH-amyloidogenesis. Overexpression of doxycycline-inducible C152A-GAPDH in SH-SY5Y neuroblastoma significantly rescued nitric oxide-induced death, concomitant with the decreased formation of GAPDH aggregates. Further, both co-immunoprecipitation assays and simulation models revealed a heterotetramer composed of one dimer each of wild-type GAPDH and C152A-GAPDH. These results suggest that the C152A-GAPDH mutant acts as a dominant-negative molecule against GAPDH aggregation via the formation of this GAPDH heterotetramer. This study may contribute to a new therapeutic approach utilizing C152A-GAPDH against brain damage in nitrosative stress-related disorders.

Interleukin 19 reduces inflammation in chemically induced experimental colitis

Inflammatory bowel disease results from chronic dysregulation of the mucosal immune system and aberrant activation of both the innate and adaptive immune responses. Interleukin (IL)-19, a member of the IL-10 family, functions as an anti-inflammatory cytokine. Here, we investigated the contribution of IL-19 to intestinal inflammation in a model of T cell-mediated colitis in mice. Inflammatory responses in IL-19-deficient mice were assessed using the 2,4,6-trinitrobenzene sulfonic acid (TNBS) model of acute colitis. IL-19 deficiency aggravated TNBS-induced colitis and compromised intestinal recovery in mice. Additionally, the exacerbation of TNBS-induced colonic inflammation following genetic ablation of IL-19 was accompanied by increased production of interferon-gamma, IL-12 (p40), IL-17, IL-22, and IL-33, and decreased production of IL-4. Moreover, the exacerbation of colitis following IL-19 knockout was also accompanied by increased production of CXCL1, G-CSF and CCL5. Using this model of induced colitis, our results revealed the immunopathological relevance of IL-19 as an anti-inflammatory cytokine in intestinal inflammation in mice.

Differences in time to peak carbachol-induced contractions between circular and longitudinal smooth muscles of mouse ileum

The muscular layer in the GI tract consists of an inner circular muscular layer and an outer longitudinal muscular layer. Acetylcholine (ACh) is the representative neurotransmitter that causes contractions in the gastrointestinal tracts of most animal species. There are many reports of muscarinic receptor-mediated contraction of longitudinal muscles, but few studies discuss circular muscles. The present study detailed the contractile response in the circular smooth muscles of the mouse ileum. We used small muscle strips (0.2 mm × 1 mm) and large muscle strips (4 × 4 mm) isolated from the circular and longitudinal muscle layers of the mouse ileum to compare contraction responses in circular and longitudinal smooth muscles. The time to peak contractile responses to carbamylcholine (CCh) were later in the small muscle strips (0.2 × 1 mm) of circular muscle (5.7 min) than longitudinal muscles (0.4 min). The time to peak contractile responses to CCh in the large muscle strips (4 × 4 mm) were also later in the circular muscle (3.1 min) than the longitudinal muscle (1.4 min). Furthermore, a muscarinic M2 receptor antagonist and gap junction inhibitor significantly delayed the time to peak contraction of the large muscle strips (4 × 4 mm) from the circular muscular layer. Our findings indicate that muscarinic M2 receptors in the circular muscular layer of mouse ileum exert a previously undocumented function in gut motility via the regulation of gap junctions.

Glyceraldehyde-3-phosphate Dehydrogenase Aggregates Accelerate Amyloid-β Amyloidogenesis in Alzheimer Disease

Alzheimer disease (AD) is a progressive neurodegenerative disorder characterized by loss of neurons and formation of pathological extracellular deposits induced by amyloid-β peptide (Aβ). Numerous studies have established Aβ amyloidogenesis as a hallmark of AD pathogenesis, particularly with respect to mitochondrial dysfunction. We have previously shown that glycolytic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) forms amyloid-like aggregates upon exposure to oxidative stress and that these aggregates contribute to neuronal cell death. Here, we report that GAPDH aggregates accelerate Aβ amyloidogenesis and subsequent neuronal cell death both in vitro and in vivo. Co-incubation of Aβ40 with small amounts of GAPDH aggregates significantly enhanced Aβ40 amyloidogenesis, as assessed by in vitro thioflavin-T assays. Similarly, structural analyses using Congo red staining, circular dichroism, and atomic force microscopy revealed that GAPDH aggregates induced Aβ40 amyloidogenesis. In PC12 cells, GAPDH aggregates augmented Aβ40-induced cell death, concomitant with disruption of mitochondrial membrane potential. Furthermore, mice injected intracerebroventricularly with Aβ40 co-incubated with GAPDH aggregates exhibited Aβ40-induced pyramidal cell death and gliosis in the hippocampal CA3 region. These observations were accompanied by nuclear translocation of apoptosis-inducing factor and cytosolic release of cytochrome c from mitochondria. Finally, in the 3×Tg-AD mouse model of AD, GAPDH/Aβ co-aggregation and mitochondrial dysfunction were consistently detected in an age-dependent manner, and Aβ aggregate formation was attenuated by GAPDH siRNA treatment. Thus, this study suggests that GAPDH aggregates accelerate Aβ amyloidogenesis, subsequently leading to mitochondrial dysfunction and neuronal cell death in the pathogenesis of AD.

Nuclear-translocated Glyceraldehyde-3-phosphate Dehydrogenase Promotes Poly(ADP-ribose) Polymerase-1 Activation during Oxidative/Nitrosative Stress in Stroke

In addition to its role in DNA repair, nuclear poly(ADP-ribose) polymerase-1 (PARP-1) mediates brain damage when it is over-activated by oxidative/nitrosative stress. Nonetheless, it remains unclear how PARP-1 is activated in neuropathological contexts. Here we report that PARP-1 interacts with a pool of glyceradehyde-3-phosphate dehydrogenase (GAPDH) that translocates into the nucleus under oxidative/nitrosative stress both in vitro and in vivo. A well conserved amino acid at the N terminus of GAPDH determines its protein binding with PARP-1. Wild-type (WT) but not mutant GAPDH, that lacks the ability to bind PARP-1, can promote PARP-1 activation. Importantly, disrupting this interaction significantly diminishes PARP-1 overactivation and protects against both brain damage and neurological deficits induced by middle cerebral artery occlusion/reperfusion in a rat stroke model. Together, these findings suggest that nuclear GAPDH is a key regulator of PARP-1 activity, and its signaling underlies the pathology of oxidative/nitrosative stress-induced brain damage including stroke.

Interleukin-19 acts as a negative autocrine regulator of activated microglia

Activated microglia can exert either neurotoxic or neuroprotective effects, and they play pivotal roles in the pathogenesis and progression of various neurological diseases. In this study, we used cDNA microarrays to show that interleukin-19 (IL-19), an IL-10 family cytokine, is markedly upregulated in activated microglia. Furthermore, we found that microglia are the only cells in the nervous system that express the IL-19 receptor, a heterodimer of the IL-20Rα and IL-20Rβ subunits. IL-19 deficiency increased the production of such pro-inflammatory cytokines as IL-6 and tumor necrosis factor-α in activated microglia, and IL-19 treatment suppressed this effect. Moreover, in a mouse model of Alzheimer's disease, we observed upregulation of IL-19 in affected areas in association with disease progression. Our findings demonstrate that IL-19 is an anti-inflammatory cytokine, produced by activated microglia, that acts negatively on microglia in an autocrine manner. Thus, microglia may self-limit their inflammatory response by producing the negative regulator IL-19.

Na/Ca(2+) exchanger 1 transgenic mice display increased relaxation in the distal colon

Na(+)/Ca(2+) exchanger 1 (NCX1) is a plasma membrane transporter involved in regulating intracellular Ca(2+) concentrations. NCX1 is critical for Ca(2+) regulation in cardiac muscle, vascular smooth muscle and nerve fibers. However, little is known about the physiological role of NCX1 in gastrointestinal motility. To determine the role of NCX1 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in smooth muscle-specific NCX1 transgenic mice (Tg). Tg show that NCX1 protein was overexpressed in the distal colon at a level twofold greater than that of endogenous NCX1. We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in Tg than in wild-type mice (WT). Under the nonadrenergic, noncholinergic condition, the EFS-induced relaxation in Tg was also greater than that in WT. Inhibition of NO synthase, CO synthase, soluble guanylate cyclase (sGC), and protein kinase G (PKG) all attenuated the enhanced relaxation in Tg, demonstrating the importance of NCX1 in NO/sGC/PKG signaling. The action of NOR-1, an NO donor, induced enhanced relaxation in Tg compared with that in WT. Unlike NOR-1, pituitary adenylate cyclase-activating peptide and vasoactive intestinal peptide induced a similar relaxation in Tg compared with that in WT. In this study, we demonstrate that NCX1 plays an important role in smooth muscle motility in the mouse distal colon.

Botulinum neurotoxin type A subtype 2 confers greater safety than subtype 1 in a rat Parkinson's disease model

Botulinum neurotoxin type A (BoNT/A) cleaves SNAP-25 and interrupts the release of acetylcholine. We previously reported that BoNT/A subtype 2 (BoNT/A2) ameliorates pathologic behavior more effectively than subtype 1 (BoNT/A1) in a rat Parkinson's disease model. Here, we further show BoNT/A2 has fewer adverse effects than BoNT/A1. We first confirmed that intrastriatal treatments of both BoNT/As had no-effect on dopaminergic terminals in the striatum. SNAP-25 cleaved by BoNT/A2 was strictly localized to the striatum on the injected side; however, SNAP-25 cleaved by BoNT/A1 diffused contralaterally. Furthermore, treatment with BoNT/A1 caused a significant reduction in body weight, while BoNT/A2 treatment did not. These results suggest that BoNT/A2 is more beneficial for clinical application against Parkinson's disease than BoNT/A1.

IL-19 reduces ligation-mediated neointimal hyperplasia by reducing vascular smooth muscle cell activation

We tested the hypothesis that IL-19, a putative member of the type 2 helper T-cell family of anti-inflammatory interleukins, can attenuate intimal hyperplasia and modulate the vascular smooth muscle cell (VSMC) response to injury. Ligated carotid artery of IL-19 knockout (KO) mice demonstrated a significantly higher neointima/intima ratio compared with wild-type (WT) mice (P = 0.04). More important, the increased neointima/intima ratio in the KO could be reversed by injection of 10 ng/g per day recombinant IL-19 into the KO mouse (P = 0.04). VSMCs explanted from IL-19 KO mice proliferated significantly more rapidly than WT. This could be inhibited by addition of IL-19 to KO VSMCs (P = 0.04 and P < 0.01). IL-19 KO VSMCs migrated more rapidly compared with WT (P < 0.01). Interestingly, there was no type 1 helper T-cell polarization in the KO mouse, but there was significantly greater leukocyte infiltrate in the ligated artery in these mice compared with WT. IL-19 KO VSMCs expressed significantly greater levels of inflammatory mRNA, including IL-1β, tumor necrosis factor α, and monocyte chemoattractant protein-1 in response to tumor necrosis factor α stimulation (P < 0.01 for all). KO VSMCs expressed greater adhesion molecule expression and adherence to monocytes. Together, these data indicate that IL-19 is a previously unrecognized counterregulatory factor for VSMCs, and its expression is an important protective mechanism in regulation of vascular restenosis.

Botulinum neurotoxin A subtype 2 reduces pathological behaviors more effectively than subtype 1 in a rat Parkinson's disease model

Recent reports indicate that interruption of acetylcholine release by intrastriatal injection of botulinum neurotoxin type A (BoNT/A) in a rat Parkinson's disease model reduces pathogenic behavior without adverse side effects such as memory dysfunction. Current knowledge suggests that BoNT/A subtype 1 (BoNT/A1) and BoNT/A subtype 2 (BoNT/A2) exert different effects. In the present study, we compared the effects of BoNT/A1 and BoNT/A2 on rotation behavior and in vivo cleavage of presynaptic protein SNAP-25 in a rat unilateral 6-hydroxydopamine-induced Parkinson's disease model. BoNT/A2 more effectively reduced pathogenic behavior by efficiently cleaving SNAP-25 in the striatum compared with that of BoNT/A1. Our results suggest that BoNT/A2 has greater clinical therapeutic value for treating subjects with Parkinson's disease compared to that of BoNT/A1.

Na⁺/Ca²⁺ exchanger 1/2 double-heterozygote knockout mice display increased nitric oxide component and altered colonic motility

The Na⁺/Ca²⁺ exchanger (NCX) is a plasma membrane transporter involved in regulating intracellular Ca²⁺ concentrations. NCX is critical for Ca²⁺ regulation in cardiac muscle, vascular smooth muscle, and nerve fibers. To determine the role of NCX1 and NCX2 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in NCX1 and NCX2 double-heterozygote knockoutmice (Double HET). We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in Double HET than in wild-type mice (WT). Under the non-adrenergic, non-cholinergic (NANC) condition, EFS-induced relaxation in Double HET was similar in amplitude to that of WT. In the experiments in which l-NNA was added under NANC conditions following the EFS, the magnitudes of EFS-induced relaxation were smaller in Double HET than those in WT. In addition, an NCX inhibitor, SN-6, enhanced EFS-induced relaxation but did not affect EFS-induced relaxation under NANC condition, as in Double HET. Moreover, the magnitudes of relaxation induced by NOR-1, which generates NO, were greater in Double HET compared with WT. Similarly, SN-6 potentiated the magnitudes of NOR-1-induced relaxation. In this study, we demonstrate that NCX regulate colonic motility by altering the sensitivity of the inhibitory component.

Na(+) /Ca(2+) exchanger 2-heterozygote knockout mice display decreased acetylcholine release and altered colonic motility in vivo

BACKGROUND

The Na(+) /Ca(2+) exchanger (NCX) is a plasma membrane transporter involved in regulating intracellular Ca(2+) concentrations. NCX is critical for Ca(2+) regulation in cardiac muscle, vascular smooth muscle, and nerve fibers. However, little is known about the physiological role of NCX in the myenteric neurons and smooth muscles of the gastrointestinal tract.

METHODS

To determine the role of NCX1 and NCX2 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in NCX1- and NCX2-heterozygote knockout mice.

KEY RESULTS

We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in NCX2 heterozygous mice (HET) than in wild-type mice (WT). Under the nonadrenergic, noncholinergic (NANC) condition, EFS-induced relaxation in NCX2 HET was similar in amplitude to that of WT. In addition, an NCX inhibitor, YM-244769 enhanced EFS-induced relaxation but did not affect EFS-induced relaxation under the NANC condition, as in NCX2 HET. Unlike NCX2 HET, NCX1 HET displayed no marked changes in colonic motility. These results indicate that cholinergic function in the colon is altered in NCX2 HET. The magnitude of acetylcholine (ACh)-induced contraction in NCX2 HET was similar to that in WT. In contrast, EFS-induced ACh release was reduced in NCX2 HET compared with that in WT.

CONCLUSIONS & INFERENCES

In this study, we demonstrate that NCX2 regulates colonic motility by altering ACh release onto the myenteric neurons of the distal colon.

IL-19 as a potential therapeutic in autoimmune and inflammatory diseases

Interleukin-19 (IL-19) is a member of the IL-10 family of cytokines. The last ten years from the finding of IL-19, investigations underline the role of IL-19 in the immunological diseases. It is known that expression of IL-19 is increased in the epidermis of patients with psoriasis, which is a Th1 dominant disease. Increased concentration of IL-19 has also been found in the serum of patients with asthma, which is a Th2 dominant disease. There is an increasing body of data demonstrating that IL-19 is associated with the pathogenesis of both Th1 and Th2 dominant diseases. Regarding the role of IL-19 on the innate immunity and inflammation, interestingly, in vitro studies have shown that lipopolysaccharide can stimulate human monocytes and macrophages to upregulate the expression of IL-19. IL- 19 is upregulated in macrophages after infection and lessens inflammation by suppressing the production of tumor necrosis factor-α , IL-6 and IL-12, but not by inducing IL-10. In addition, IL-19-deficient mice are susceptible to experimental colitis induced by dextran sodium sulfate, a disease which is characterized by excessive inflammatory responses of local macrophages and epithelial cells to intestinal microflora. In this review, we discuss our current understanding of the role of IL-19 in autoimmune and inflammatory diseases.

A rapid, targeted, neuron-selective, in vivo knockdown following a single intracerebroventricular injection of a novel chemically modified siRNA in the adult rat brain

There has been a dramatic expansion of the literature on RNA interference and with it, increasing interest in the potential clinical utility of targeted inhibition of gene expression and associated protein knockdown. However, a critical factor limiting the experimental and therapeutic application of RNA interference is the ability to deliver small interfering RNAs (siRNAs), particularly in the central nervous system, without complications such as toxicity and inflammation. Here we show that a single intracerebroventricular injection of Accell siRNA, a new type of naked siRNA that has been modified chemically to allow for delivery in the absence of transfection reagents, even into differentiated cells such mature neurons, leads to neuron-specific protein knockdown in the adult rat brain. Following in vivo delivery, targeted Accell siRNAs were incorporated successfully into various types of mature neurons, but not glia, for 1 week in diverse brain regions (cortex, striatum, hippocampus, midbrain, and cerebellum) with an efficacy of delivery of approximately 97%. Immunohistochemical and Western blotting analyses revealed widespread, targeted inhibition of the expression of two well-known reference proteins, cyclophilin-B (38-68% knockdown) and glyceraldehyde 3-phosphate dehydrogenase (23-34% knockdown). These findings suggest that this novel procedure is likely to be useful in experimental investigations of neuropathophysiological mechanisms.

Adenosine and ATP affect LPS-induced cytokine production in canine macrophage cell line DH82 cells

Macrophages are essential for controlling the majority of infections, and are mediators of natural immunity. During infection, lipopolysaccharide (LPS) stimulates macrophages to produce pro-inflammatory cytokines. Adenosine and ATP released into the extracellular space by immunological stimuli have been shown to regulate various immune functions. More recently, it has been shown adenosine and ATP have a critical role on the physiological negative feedback mechanism for limitation and termination of tissue-specific and systemic inflammatory responses. It was useful and meaningful to gain information about interaction between LPS, which generates the inflammation, and adenosine and ATP, which terminate the inflammation. We evaluate effects of adenosine and ATP on the production of cytokines related to inflammation in canine macrophage cell line DH82 cells. Adenosine and ATP respectively increased the production of IL-10 without affecting the production of IL-6, TNF-α and IL-12 in DH82 cells. In addition, adenosine and ATP prevented the production of LPS-induced IL-6, TNF-α and IL-12 in DH82 cells. In contrast, adenosine and ATP potentiated LPS-induced IL-10 production in DH82 cells. Moreover, adenosine, but not ATP inhibited LPS-induced expression of TLR4 in DH82 cells. These results suggest that conditions related to increased adenosine and/or ATP may play an important role in the inflammatory reactions.

Clofibrate Relaxes the Longitudinal Smooth Muscle of the Mouse Distal Colon through Calcium-Mediated Desensitisation of Contractile Machinery

Peroxisome proliferator-activated receptor α (PPAR-α) is a ligand-activated transcription factor that exerts strong effects on metabolic pathways. Our aim was to elucidate the effect of clofibrate, a PPAR-α agonist, on the longitudinal muscle of the mouse distal colon. We initially found that clofibrate induced a relaxation response in this muscle. Notably, the PPAR-α antagonists GW9662 and T0070907 did not attenuate this clofibrate-induced relaxation. The structurally related PPAR-α agonists fenofibrate and bezafibrate induced relaxation in the distal colon as effectively as clofibrate. In contrast, wy-14643, which activates PPAR-α more selectively than clofibrate, had no effect. Furthermore, clofibrate-induced relaxation was not affected by N-nitro-<i>L</i>-arginine, an NO synthase inhibitor, 1H-[1,2,4]-oxadiazolo-[4,3- a]quinoxaline-1-one, a soluble guanylate cyclase inhibitor, or H89, a protein kinase A inhibitor. Tetrodotoxin, an Na⁺ channel blocker, and glibenclamide, apamin, charybdotoxin and XE991, various K⁺ channel blockers, had no effect on clofibrate-induced relaxation. Importantly, clofibrate induced a relaxation response that was not accompanied by any alteration in the cytoplasmic Ca²⁺ concentration in the longitudinal muscle of the mouse distal colon. Moreover, calyculin A, a myosin light-chain phosphatase (MLCP) inhibitor, attenuated clofibrate-induced relaxation. Our findings indicate that clofibrate relaxes the longitudinal smooth muscle of the mouse distal colon by regulating MLCP activity.