Background:Coronary microvascular dysfunction (CMD) is increasingly recognized as a key contributor to angina and non-obstructive coronary arteries (ANOCA) and adverse cardiovascular outcomes. Despite its clinical importance, the molecular basis of CMD remains to be fully elucidated. CMD is known to be associated with systemic microvascular endothelial dysfunction. Methods:We examined serum levels of molecules crucial for endothelium-dependent vasodilation, especially nitric oxide (NO)- mediated responses and endothelium-dependent hyperpolarizing responses. These included caveolin-1 (Cav1), endothelial NO synthase (eNOS), and Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in patients with ANOCA enrolled in the nationwide registry by the Japanese Association of CMD. Results:This multicenter study included 295 ANOCA patients (M/F 134/161, mean age 63.7 ± 13.9 years). All patients underwent coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) measurements for CMD diagnosis. Serum Cav1, eNOS, and Cu,Zn-SOD levels were quantified by enzyme-linked immunosorbent assay. CMD was identified in 43% of patients who showed significantly lower Cu,Zn-SOD levels than non-CMD patients (P = 0.001). In patients with abnormal IMR, Cu,Zn-SOD was particularly reduced, while those with both abnormal CFR and IMR had reduced Cav1. In contrast, eNOS levels did not differ significantly between groups. Multivariable logistic regression analysis revealed that Cu,Zn-SOD levels below the cut-off value (97.2 ng/ml) independently predicted CMD [odds ratio (95% confidence interval) 2.71 (1.56-4.74), P < 0.001]. Conclusions:Reduced Cu,Zn-SOD levels are associated with CMD, suggesting enhanced systemic oxidative stress. This reduction may impair the endothelium-derived hyperpolarizing factor pathway, thereby contributing to CMD pathophysiology.

Background: Aortic dissection (AD) is a catastrophic disease with high mortality and serious complications, and its molecular pathogenesis is largely unknown. The importance of inflammation in AD has been reported. Recently we found that cell proliferation precedes the inflammatory response in AD. Cell proliferation causes cellular senescence that induces inflammatory response, however, role of cellular senescence in AD has not been elucidated. Objective: We investigated if cellular senescence contributes to AD pathogenesis in mouse AD model. Methods and Results: A mouse AD model was created by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII) for 14days. BAPN+AngII infusion induced senescence markers from day 3, before AD onset, and persisted until day14. Senescent cells, as demonstrated by the expression of senescence-associated beta-galactosidase, were evident in intimal endothelial cells, medial smooth muscle cells, adventitial macrophages, and fibroblasts. To examine role of cellular senescence in AD, we orally administrated ABT263 known as “senolytics” that eliminates senescent cells. ABT263 treatment reduced the expression of the senescence markers. The AD mortality of ABT263 group was 35%, which was lower than that of vehicle group(66.7%, P < 0.05 by log-rank test). The severity of AD, as assessed by the lesion length in vehicle group was 33.2 ± 3.1mm, whereas that in ABT263 group was 24.6 ± 1.8mm (P < 0.05). Transcriptome analysis revealed that ABT263 treatment suppressed the immune and inflammatory response in the aorta before AD onset. Quantitative RT-PCR confirmed that ABT263 treatment prevented the induction of p21Cip1, interleukin-6 and several chemokines. Bioplex analysis of mice’s serum showed that ABT263 decreased inflammatory molecules in mice’s serum compared to vehicle group. Moreover, aortic smooth muscle cells(SMCs)remained contractile phenotype in ABT263 group, whereas BAPN+AngII reduced the phenotype in vehicle group. Conclusions: Elimination of senescent cells prevented AD progression and death in mice. ABT263 suppressed the inflammatory response and contributed to retain the SMCs phenotype. Cellular senescence represents a potential predictor and a therapeutic target for AD.

BACKGROUND:Although recent studies have revealed the importance of inflammation in the pathogenesis of aortic dissection (AD), little is known about the relationships among inflammatory cells in human AD tissue. METHODS AND RESULTS:We assessed the relationships among various immune cell types, including neutrophils, macrophages (M1 and M2), B cells, and helper T cells (Th1, Th2, Th17, Treg and Tfh ) in human AD tissue. AD tissues displayed abundant infiltration of immune cells. Correlation analysis revealed two groups of highly correlated cell types: a group of neutrophils and M1 and M2 macrophages, and another group consisting of B cells and helper T cells. In one particular case of AD, we were able to analyze the correlations between neutrophils and M1 and M2 macrophages in the entry, border, and intact zones of the AD lesions. Neutrophils showed significant correlations with M1 and M2 macrophages in the border zones. The entry and border zones showed M1-dominant polarization, whereas the intact zone showed M2-dominant polarization. CONCLUSIONS:These findings indicate the existence of cell type-specific and site-specific interactions among immune cell types in human AD tissues.

Abstract Background Aortic dissection (AD) is a devastating aortic disease with high mortality, for which molecular pathogenesis is largely unknown. Recent studies have highlighted the importance of inflammatory response in AD. We have reported that B cells and immunoglobulins promote inflammatory response in the aorta and are involved in the pathogenesis of abdominal aortic aneurysm, another form of aortic disease. However, it is not known whether and how B cells participate in AD development or progression. Methods and results Immunohistochemical staining of human AD tissue revealed that B cells were clustered together with T cells, macrophages, and neutrophils at the entry site of AD with medial disruption. B cell cluster was also observed at the site of medial disruption in mouse model of AD that was induced by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII). In muMT mouse, which is genetically deficient for B cells and immunoglobulins, BAPN+AngII induced significantly less severe AD compared to that in wild type. The rate of aortic rupture and sudden death was approximately 42% in wild type mice, while that in muMT mouse was 12% (P<0.05). Administration of mouse normal polyclonal IgG to muMT mice resulted in dramatic increase in aortic rupture and sudden death, starting at day 7 of BAPN+AngII infusion, and reaching 69% of rupture rate, indicating the critical role of IgG in AD. Transcriptome analysis revealed that IgG administration enhanced the expression of inflammation-related genes in muMT mice before BAPN+AngII infusion, indicating that IgG increased susceptibility to AD. Immunohistochemistry of aorta confirmed exogenous IgG deposition, colocalized with C3, which is known to contribute to innate immunity. Conclusion These findings demonstrated B cells and IgG are critically involved in the destructive inflammation of AD pathogenesis. Further, the aortic deposition of IgG and C3, a part of the components of innate immunity, precedes the development of AD. These findings may provide the therapeutic opportunities to AD.

Inflammation is a key process in cardiovascular diseases. The extracellular matrix (ECM) of the vasculature is a major target of inflammatory cytokines, and TNF α regulates ECM metabolism by affecting collagen production. In this study, we have examined the pathways mediating TNF α - induced suppression of prolyl-4 hydroxylase alpha1 (P4H α 1), the rate-limiting isoform of P4H responsible for procollagen hydroxylation, maturation

Abstract Background Aortic dissection (AD) is a fatal disease where the intimomedial layer of the aorta suddenly fail. Although it is widely accepted that hemodynamic stress on the aortic wall triggers its destruction that is further promoted by inflammatory response as exemplified by the infiltration of neutrophils and macrophages, molecular mechanism is unknown for the link of aortic wall stress, inflammation and tissue destruction. In general, mechanical stress to the tissue is converted to the cellular response through the cell adhesion molecules and the activation of focal adhesion kinase (Fak). Although it has been reported that Fak is involved in pathogenesis of aortic aneurysm by promoting migration and activation of macrophages, its role in AD is unknown. We hypothesized that Fak may be involved in AD pathogenesis. Purpose We investigated the involvement of Fak in AD pathogenesis, focusing on its role in inflammatory cells. Methods and results We created a mouse model of AD by continuous infusion of beta-aminopropionitrile, a collagen crosslink inhibitor, and angiotensin II (BAPN + Ang II). Immunostaining for activated Fak revealed that Fak was not activated in normal aorta, but was activated in the infiltrating inflammatory cells and in interstitial cells of the aortic wall after AD development. We examined the role of Fak by oral administration of PND-1186, a specific Fak inhibitor, in mouse AD model. Vehicle-treated group showed 63.6% mortality, whereas PND-1186-treated group showed 20% mortality (P<0.01, n=20 for each group) in 14 days of the observational period. The aortic arch lesion, the most critical part in AD, was improved from 1.96±0.41 mm in vehicle group to 0.66±0.29 mm in PND group (P<0.05). We next examined the cell type-specific role of Fak in AD by creating macrophage and granulocyte-specific deletion of Fak driven by LysM-Cre and floxed Fak system. Unexpectedly, the genetic deletion of Fak in macrophages and granulocytes had no impact on the mortality nor the severity of AD. Conclusions These findings proved that Fak plays a critical role in AD progression and death. Because Fak is dispensable for macrophages and granulocytes, other cell types, possibly aortic wall interstitial cells, may be regulated by Fak in AD pathogenesis. Deciphering the role of Fak would provide the fundamental understanding of AD pathogenesis. Funding Acknowledgement Type of funding sources: None.

Objective Postoperative intrapericardial adhesion increases the risk of complications in patients undergoing reoperation. We investigated the effect of a bioabsorbable dextrin hydrogel (DHG) on the formation of intrapericardial adhesions. Methods Intrapericardial adhesion was surgically induced in Japanese white rabbits with DHG treatment (Adh + DHG) or without DHG treatment (Adh). The sham group was not treated with DHG and intrapericardial adhesion was not induced. The extent of intrapericardial adhesion was assessed by adhesion scoring and crystal violet staining of the pericardial cavity. Bromodeoxyuridine (BrdU) uptake assay was performed to assess the proliferative response to the injury in the tissue beneath the intrapericardial adhesion. Results The Adh + DHG group showed looser intrapericardial adhesions compared to the Adh group. The adhesion area of the Adh + DHG group was 4.6 ± 2.2%, whereas that of the Adh group was 32.6 ± 6.4% at the end of the 28-day observation period ( p < 0.01). The induction of intrapericardial adhesion resulted in a proliferative response mainly in the cardiac tissue just beneath the adhesion. There were 48.6 ± 10.7 cells/0.1 mm 2 BrdU-positive cells in the Adh + DHG group and 135.7 ± 23.8 cells/0.1 mm 2 BrdU-positive cells in the Adh group on day 28 ( p < 0.05). Conclusion These findings indicate that DHG effectively prevented intrapericardial adhesion in this model.

Traditionally, patients with end-stage heart failure (HF) have rarely been involved in end-of-life care (EOLC) discussions in Japan. The purpose of this study was to examine the impact of HF-specific palliative care team (HF-PCT) activities on EOLC discussions with patients, HF therapy and care, and food intake at the end of life. We retrospectively analyzed 52 consecutive patients with HF (mean age, 70 ± 15 years; 42% female) who died at our hospital between May 2013 and July 2020 and divided them into two groups: before (Era 1, n = 19) and after (Era 2, n = 33) the initiation of HF-PCT activities in June 2015. Compared to Era 1, Era 2 showed a decrease in invasive procedures, an increase in opioid and non-intubating sedative use for symptom relief, improved quality of meals at the end of life, and an increase in participation in EOLC discussions. The administration of artificial nutrition in the final three days was associated with non-ischemic cardiomyopathy etiology, the number of previous hospitalizations for HF, and multidisciplinary EOLC discussion support. HF-PCT activities may provide an opportunity to discuss EOLC with patients, reduce the burden of physical and psychological symptoms, and shift the goals of end-of-life nutritional intake to ensure comfort and quality of life.

Tenascins are a family of multifunctional extracellular matrix (ECM) glycoproteins with time- and tissue specific expression patterns during development, tissue homeostasis, and diseases. There are four family members (tenascin-C, -R, -X, -W) in vertebrates. Among them, tenascin-X (TNX) and tenascin-C (TNC) play important roles in human pathologies. TNX is expressed widely in loose connective tissues. TNX contributes to the stability and maintenance of the collagen network, and its absence causes classical-like Ehlers-Danlos syndrome (clEDS), a heritable connective tissue disorder. In contrast, TNC is specifically and transiently expressed upon pathological conditions such as inflammation, fibrosis, and cancer. There is growing evidence that TNC is involved in inflammatory processes with proinflammatory or anti-inflammatory activity in a context-dependent manner. In this review, we summarize the roles of these two tenascins, TNX and TNC, in cardiovascular and inflammatory diseases and in clEDS, and we discuss the functional consequences of the expression of these tenascins for tissue homeostasis.

Aortic dissection (AD) is a medical emergency, in which acute destruction of aortic wall occurs with unknown etiology. Recent studies have uncovered the critical role of inteleukin-6 (IL-6) and inflammatory cells including macrophages in the disease mechanism of AD. IL-6 activates janus kinase and signal transducer and activator of transcription 3 (STAT3) to alter the gene expression program in many cell types, thus regulating various aspects of inflammatory response. We found that in human AD tissue, STAT3 was activated in infiltrating macrophages and in medial smooth muscle cells (SMCs), suggesting that STAT3 may regulate the response of these cell types. However, it is unknown how Stat3 regulates the cell type-specific response in pathogenesis of AD. The role of STAT3 was examined in genetically modified mice in which STAT3 sensitivity was enhanced specifically in macrophages or in SMCs by tissue-specific deletion of suppressor of cytokine signaling 3 (Socs3), a negative regulator of STAT3. Macrophage-specific deletion of Socs3 caused acute enhancement of STAT3 activation, M1-dominant differentiation of macrophages, suppression of tissue repair response of SMCs, and exaggerated AD. In contrast, SMC-specific deletion of Socs3 caused chronic STAT3 activation and low-grade inflammatory response in aortic walls, activation of fibroblasts, M2-dominant differentiation of macrophages, increase in adventitial collagen deposition, resulting in the protection of aorta from AD by reinforcing the tensile strength of the aortic walls. Therefore, STAT3 regulates the balance between the destruction and the reinforcement of the aortic tissue, depending on the cell types and the time course of STAT3 activation, which ultimately regulates the development of AD. Elucidating such a dynamic mechanism to regulate the aortic tissue integrity would be essential to decipher the molecular pathogenesis of AD.

Ongoing aortic wall degeneration and subsequent aneurysm exclusion failure are major concerns after an endovascular aneurysm repair with a stent-graft. An ideal solution would be a drug therapy that targets the aortic wall and inhibits wall degeneration. Here, we described a novel drug delivery system, which allowed repetitively charging a graft with therapeutic drugs and releasing them to the aortic wall in vivo. The system was composed of a targeted graft, which was labeled with a small target molecule, and the target-recognizing nanocarrier, which contained suitable drugs. We developed the targeted graft by decorating a biotinylated polyester graft with neutravidin. We created the target-recognizing nanocarrier by conjugating drug-containing liposomes with biotinylated bio-nanocapsules. We successfully demonstrated that the target-recognizing nanocarriers could bind to the targeted graft, both in vitro and in blood vessels of live mice. Moreover, the drug released from our drug delivery system reduced the expression of matrix metalloproteinase-9 in mouse aortas. Thus, this hybrid system represents a first step toward an adjuvant therapy that might improve the long-term outcome of endovascular aneurysm repair.

Aortic dissection (AD) is the acute destruction of aortic wall and is reportedly induced by inflammatory response. Here we investigated the role of smooth muscle Socs3 (a negative regulator of Janus kinases/signal transducer and activator of transcription signaling) in AD pathogenesis using a mouse model generated via β-aminopropionitrile and angiotensin II infusion. Socs3 deletion specifically in smooth muscle cells yielded a chronic inflammatory response of the aortic wall, which was associated with increased fibroblasts, reinforced aortic tensile strength, and less-severe tissue destruction. Although an acute inflammatory response is detrimental in AD, smooth muscle-regulated inflammatory response seemed protective against AD.

Abstract Background Aortic dissection (AD) is a serious clinical condition that frequently results in fatal outcome. Although recent studies indicate the critical role of inflammation in AD, the molecular pathogenesis of AD is still unclear. Syk is a tyrosine kinase that regulates multiple types of inflammatory cells. Syk is also reported to regulate the function of smooth muscle cells (SMCs), the major component of aortic walls. It is unknown whether and how Syk is involved in AD pathogenesis. Objective In the current study, we investigated the role of Syk in AD. Methods and results A mouse AD model was created by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII) that caused progressive development of AD from day 7, reaching approximately 80% of AD incidence at day 14. Western blot analysis for activated (phosphorylated) Syk (pSyk) revealed Syk activation at day 3 of BAPN+AngII infusion, followed by transient suppression at day 7, and reactivation at day 14. Double immunofluorescence staining for pSyk and smooth muscle alpha actin showed that Syk was active not only in the infiltrating inflammatory cells, but also in SMCs in AD. Treatment of mice with fostamatinib, a specific Syk inhibitor, resulted in more severe AD compared to the vehicle treatment. The AD lesion length was 3.80±0.86 mm in the vehicle group and 8.87±1.69 mm in the fostamatinib group (P<0.05). Fostamatinib worsened the mortality of mice due to the aortic rupture from 0% in the vehicle group and 42% in the fostamatinib group (P<0.05). Transcriptome analysis revealed that fostamatinib suppressed both positive and negative regulators of inflammatory and defense responses. BAPN+AngII infusion caused activation of Stat3, a critical regulator of inflammatory response, which was suppressed by fostamatinib. As we previously reported that Stat3 activation in SMCs is protective against AD, we examined the relationship between Syk and Stat3 in SMCs in culture. BAPN+AngII challenge caused activations of Syk and Stat3, both of which were suppressed by fostamatinib, indicating that Stat3 was under the control of Syk in the AD model and in SMCs. Conclusions These findings uncovered the previously unrecognized role of Syk for protecting the aortic tissue in AD pathogenesis, possibly by activating the protective mechanism of aortic walls including Stat3 in SMCs. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant from Japan Society for the Promotion of Science

Aortic dissection (AD) is a serious clinical condition that is unpredictable and frequently results in fatal outcome. Although rapamycin, an inhibitor of mechanistic target of rapamycin (mTOR), has been reported to be effective in preventing aortopathies in mouse models, its mode of action has yet to be clarified. A mouse AD model that was created by the simultaneous administration of β-aminopropionitrile (BAPN) and angiotensin II (AngII) for 14 days. Rapamycin treatment was started either at day 1 or at day 7 of BAPN+AngII challenge, and continued throughout the observational period. Rapamycin was effective both in preventing AD development and in suppressing AD progression. On the other hand, gefitinib, an inhibitor of growth factor signaling, did not show such a beneficial effect, even though both rapamycin and gefitinib suppressed cell cycle activation in AD. Rapamycin suppressed cell cycle-related genes and induced muscle development-related genes in an AD-related gene expression network without a major impact on inflammation-related genes. Rapamycin augmented the activation of Akt1, Akt2, and Stat3, and maintained the contractile phenotype of aortic smooth muscle cells. These findings indicate that rapamycin was effective both in preventing the development and in suppressing the progression of AD, indicating the importance of the mTOR pathway in AD pathogenesis.

Objective: Inflammatory response is central to pathogenesis of abdominal aortic aneurysm (AAA). Recently, we reported that Syk, a signaling molecule in inflammatory cells, promotes AAA development in a mouse model. In this study, we aimed to investigate the role of Syk in human AAA pathogenesis. Materials and Methods: We obtained human AAA wall samples during open surgical aortic repair at Kurume University Hospital. Immunohistochemical analyses of AAA samples were performed for Syk activation and cell type markers. Ex vivo culture of human AAA tissue was utilized to evaluate the effect of P505-15, a Syk inhibitor, on secretions of interleukin-6 (IL-6) and matrix metalloproteinases (MMPs). Results: Immunohistochemical analysis showed infiltration of B cells, T cells, and macrophages in AAA samples. Syk activation was localized mainly in B cells and part of macrophages. AAA tissue in culture secreted IL-6, MMP-9, and MMP-2 without any stimulation. The unstimulated secretions of IL-6, MMP-9, and MMP-2 were insensitive to P505-15. Secretions of IL-6 and MMP-9 were enhanced by exogenous normal human immunoglobulin G (IgG), which was suppressed by P505-15, whereas secretion of MMP-2 was insensitive to IgG or P505-15. Conclusion: These results demonstrate an important role of Syk for IgG-dependent inflammatory response in human AAA.

われわれは，大動脈解離で重要とされる炎症応答の解析を行った。ヒト解離組織ではマクロファージと平滑筋細胞で代表的な炎症シグナル分子であるSTAT3が活性化していた。マウス解離モデルの解析から，マクロファージSTAT3は解離を増悪させ，平滑筋細胞STAT3は解離を抑制することが示された。解離病態において，STAT3による炎症応答は組織破壊と組織保護という2面性を持つと考えられた。

Aortic dissection (AD) is one of the destructive and fatal aortic diseases, for which molecular pathogenesis is largely unknown. Recent studies have highlighted the importance of inflammatory response in AD. We and others reported that B cells and immunoglobulins participate in pathogenesis of abdominal aortic aneurysm, another form of aortic destructive disease, by promoting inflammatory response. It is not known whether and how B cells participate in AD pathogenesis. Immunohistochemical staining of human AD tissue revealed that B cells were clustered together with T cells, macrophages and neutrophils at the entry site of AD with medial disruption. B cell cluster was also observed at the site of medial disruption in mouse model of AD that was induced by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII). In muMT mouse, which is deficient for B cells and immunoglobulins due to genetic deletion of immunoglobulin heavy chain, BAPN+AngII induced significantly less severe AD compared to that in wild type. Depositions of IgG and fibrinogen, one of the endogenous antigen for natural IgG, were observed after BAPN+AngII infusion before and after AD development in wild type mice. Deposition of fibrinogen was also observed in mMT mice after BAPN+AngII infusion. The rate of aortic rupture and sudden death was approximately 42% in wild type mice, while that in muMT mouse was 12% (P<0.05). Administration of mouse normal polyclonal IgG to muMT mice resulted in dramatic increase in aortic rupture and sudden death, starting at day 7 of BAPN+AngII infusion, and reaching 69% of rupture rate, indicating the critical role of IgG in AD. These findings demonstrated B cells and IgG are critically involved in the destructive inflammation of AD pathogenesis. Further, the deposition of fibrinogen, one of the targets of natural IgG, precedes the development of AD. Our findings may provide the conceptual foundation of the diagnostic strategy for on-going tissue destruction and for the therapeutic opportunities to intervene the progressive tissue destruction in AD. Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science

Aortic dissection (AD) is a major cause of acute aortic syndrome with high mortality due to the destruction of aortic walls. Although recent studies indicate the critical role of inflammation in the disease mechanism of AD, it is unclear how inflammatory response is initiated. Here, we demonstrate that myocardin-related transcription factor A (MRTF-A), a signal transducer of humoral and mechanical stress, plays an important role in pathogenesis of AD in a mouse model. A mouse model of AD was created by continuous infusion of angiotensin II (AngII) that induced MRTF-A expression and caused AD in 4 days. Systemic deletion of Mrtfa gene resulted in a marked suppression of AD development. Transcriptome and gene annotation enrichment analyses revealed that AngII infusion for 1 day caused pro-inflammatory and pro-apoptotic responses before AD development, which were suppressed by Mrtfa deletion. AngII infusion for 1 day induced pro-inflammatory response, as demonstrated by expressions of Il6, Tnf, and Ccl2, and apoptosis of aortic wall cells, as detected by TUNEL staining, in an MRTF-A-dependent manner. Pharmacological inhibition of MRTF-A by CCG-203971 during AngII infusion partially suppressed AD phenotype, indicating that acute suppression of MRTF-A is effective in preventing the aortic wall destruction. These results indicate that MRTF-A transduces the stress of AngII challenge to the pro-inflammatory and pro-apoptotic responses, ultimately leading to AD development. Intervening this pathway may represent a potential therapeutic strategy.

BACKGROUND Interleukin (IL)-22, a member of the IL-10 cytokine family, is the only known cytokine that is secreted by immune cells but does not target immune cells; it mainly targets epithelial cells. In this study, we aimed to determine whether IL-22 administration could activate the myocardial STAT3 (signal transducer and activator of transcription-3) signaling pathway, and thus prevent myocardial injury, in a mouse model of ischemia reperfusion injury. METHODS AND RESULTS We evaluated the STAT3 activation after IL-22 injection by Western blot analysis and immunostaining for phosphorylated STAT3 in the heart and found that STAT3 activation in heart tissue rapidly peaked after IL-22 injection. Coimmunostaining of phosphorylated STAT3 and alpha-actinin revealed that STAT3 activation occurred in cardiomyocytes after IL-22 administration. In heart tissue from intact mice, real-time PCR demonstrated significant expression of IL-22 receptor subunit 1, and coimmunostaining of IL-22 receptor subunit 1 and alpha-actinin showed IL-22 receptor subunit 1 expression in cardiomyocytes. In cultured cardiomyocytes, IL-22 activated STAT3, and we detected IL-22 receptor subunit 1 expression. Overall, these results indicated that IL-22 directly activated the myocardial IL-22-receptor subunit 1-STAT3 signaling pathway. Following ischemia reperfusion, compared with PBS-treated mice, IL-22-treated mice exhibited a significantly reduced infarct size, significantly reduced myocardial apoptosis, and significantly enhanced phosphorylated STAT3 expression. Moreover, heart tissue from IL-22-treated mice exhibited a significantly reduced expression ratio of phosphorylated p53 to p53. CONCLUSIONS Our present findings suggest that IL-22 directly activated the myocardial STAT3 signaling pathway and acted as a cardioprotective cytokine to ameliorate acute myocardial infarction after ischemia reperfusion.

Aortic dissection (AD) is a fatal disease due to the sudden destruction of the aortic medial layer. Currently, Molecular pathogenesis of AD is unknown. We investigated the role of focal adhesion kinase (FAK), a mechanosensitive signal transducer, in AD pathogenesis. We created a mouse model of AD with a continuous infusion of beta-aminopropionitrile (150 mg/kg/day), a collagen crosslink inhibitor, and angiotensin II (1,000 ng/kg/min) (BAPN + Ang II) by osmotic pumps. This AD model showed about 60% mortality within 2 weeks due to AD rupture. Immunohistochemical staining for activated FAK revealed that FAK was inactive in normal mouse aorta, but was strongly activated in the aortic walls after BAPN + Ang II infusion. Immunofluorescence staining showed that FAK was activated mainly in smooth muscle cells after the BAPN + Ang II challenge. Western blot analysis revealed that FAK was activated in 3 days after BAPN + Ang II infusion before AD development, followed by transient reduction at day 7, and re-activation after AD development at day 14. We examined the effect of PND-1186, an orally available FAK inhibitor, on the severity as determined by the AD lesion length and the mortality of AD. Mice were administered with either vehicle or PND-1186 (150 mg/kg twice daily by oral gavage) during the BAPN + Ang II challenge (n=20 for each group). Administration of PND-1186 resulted in significant reduction in the lesion length of AD (vehicle; 12.5 ± 1.65 mm, PND; 7.46 ± 1.88 mm, P<0.05). The suppressive effect of PND-1186 was most significant in the aortic arch (vehicle; 2.13 ± 0.29 mm, PND; 0.85 ± 0.22 mm, P<0.01). Furthermore, PND-1186 significantly improved the survival rate of mice from 40.0% to 80.0% (P<0.01). Transcriptome analysis indicated that destruction and inflammation of tissue were suppressed by PND-1186 administration. These findings indicated that FAK plays an important role in AD pathogenesis, possibly by transducing the pathological stress to the tissue destructive response in the aortic walls. We propose that FAK is a potential therapeutic target to limit the fatal destruction of aortic walls in AD.