Substance P Inhibits the Collagen Synthesis of Rat Myocardial Fibroblasts Induced by Ang II

Cellular metabolism of substance P produces neurokinin-1 receptor peptide agonists with diminished cyclic AMP signaling

Substance P (SP) is released from sensory nerves in the arteries and heart. It activates neurokinin-1 receptors (NK1Rs) causing vasodilation, immune modulation, and adverse cardiac remodeling. The hypothesis was tested: SP and SP metabolites activate different second messenger signaling pathways. Macrophages, endothelial cells, and fibroblasts metabolized SP to N- and C-terminal metabolites to varying extents. SP 5-11 was the most abundant metabolite followed by SP 1-4, SP 7-11, SP 6-11, SP 3-11, and SP 8-11. In NK1R-expressing human embryonic kidney 293 (HEK293) cells, SP and some C-terminal SP metabolites stimulate the NK1R, promoting the dissociation of several Gα proteins, including Gαs and Gαq from their βγ subunits. SP increases intracellular calcium concentrations ([Ca]i) and cyclic 3',5'-adenosine monophosphate (cAMP) accumulation with similar -log EC50 values of 8.5 ± 0.3 and 7.8 ± 0.1 M, respectively. N-terminal metabolism of SP by up to five amino acids and C-terminal deamidation of SP produce peptides that retain activity to increase [Ca]i but not to increase cAMP. C-terminal metabolism results in the loss of both activities. Thus, [Ca]i and cAMP signaling are differentially affected by SP metabolism. To assess the role of N-terminal metabolism, SP and SP 6-11 were compared with cAMP-mediated activities in NK1R-expressing 3T3 fibroblasts. SP inhibits nuclear factor κB (NF-κB) activity, cell proliferation, and wound healing and stimulates collagen production. SP 6-11 had little or no activity. Cyclooxygenase-2 (COX-2) expression is increased by SP but not by SP 6-11. Thus, metabolism may select the cellular response to SP by inhibiting or redirecting the second messenger signaling pathway activated by the NK1R.NEW & NOTEWORTHY Endothelial cells, macrophages, and fibroblasts metabolize substance P (SP) to N- and C-terminal metabolites with SP 5-11 as the most abundant metabolite. SP activates neurokinin-1 receptors to increase intracellular calcium and cyclic AMP. In contrast, SP metabolites of N-terminal metabolism and C-terminal deamidation retain the ability to increase calcium but lose the ability to increase cyclic AMP. These new insights indicate that the metabolism of SP directs cellular functions by regulating specific signaling pathways.

MircroRNA-145 Attenuates Cardiac Fibrosis Via Regulating Mitogen-Activated Protein Kinase Kinase Kinase 3

PURPOSE

This study aimed to explore the effect of microRNA (miR)-145 on cardiac fibrosis in heart failure mice and its target.

METHODS

Experiments were carried out in mice receiving left coronary artery ligation, transverse aortic constriction (TAC), or angiotensin (Ang) II to trigger heart failure, and in cardiac fibroblasts (CFs) with Ang II-induced fibrosis.

RESULTS

The miR-145 levels were decreased in the mice hearts of heart failure induced by myocardial infarction (MI), TAC or Ang II infusion, and in the Ang II-treated CFs. The impaired cardiac function was ameliorated by miR-145 agomiR in MI mice. The increased fibrosis and the levels of collagen I, collagen III, and transforming growth factor-beta (TGF-β) in MI mice were inhibited by miR-145 agomiR or miR-145 transgene (TG). The agomiR of miR-145 also attenuated the increases of collagen I, collagen III, and TGF-β in Ang II-treated CFs. Bioinformatics analysis and luciferase reporter assays indicated that mitogen-activated protein kinase kinase kinase 3 (MAP3K3) was a direct target gene of miR-145. MAP3K3 expression was suppressed by MiR-145 in CFs, while the MAP3K3 over-expression reversed the inhibiting effects of miR-145 agomiR on the Ang II-induced increases of collagen I, collagen III, and TGF-β in CFs.

CONCLUSION

These results indicated that miR-145 upregulation could improve cardiac dysfunction and cardiac fibrosis by inhibiting MAP3K3 in heart failure. Thus, upregulating miR-145 or blocking MAP3K3 can be used to treat heart failure and cardiac fibrosis.

MicroRNA-19 upregulation attenuates cardiac fibrosis via targeting connective tissue growth factor

BACKGROUND

Previous studies have shown the role of microRNA (miR)-19 in aging-related heart failure. The present study aimed to verify the effects of miR-19 on cardiac fibrosis and its target.

METHODS

Cardiac fibrosis was induced by myocardial infarction (MI)-induced heart failure and angiotensin (Ang) II-treated rats in vivo, and was induced in Ang II-treated cardiac fibroblasts (CFs) in vitro.

RESULTS

The expression of miR-19 was reduced in the heart tissue of MI and Ang II-treated rats, and Ang II-treated CFs. The impaired cardiac function in rats was repaired after miR-19 administration. The levels of collagen I, collagen III and transforming growth factor-beta (TGF-β) increased in the heart tissue of MI and Ang II-treated rats, and Ang II-treated CFs. These increases were reversed by miR-19 agomiR. Moreover, the bioinformatic analysis and luciferase reporter assays demonstrated that connective tissue growth factor (CTGF) was a direct target of miR-19. MiR-19 treatment inhibited CTGF expression in CFs, while CTGF overexpression inhibited miR-19 agomiR to attenuate the Ang II-induced increases of collagen I and collagen III in CFs. The increases of p-ERK, p-JNK and p-p38 in the CFs induced by Ang II were repressed by miR-19 agomiR.

CONCLUSIONS

Upregulating miR-19 can improve cardiac function and attenuate cardiac fibrosis by inhibiting the CTGF and MAPK pathways.

The neuropeptide substance P/neurokinin-1 receptor system and diabetes: From mechanism to therapy

Diabetes is a significant public health issue known as the world's fastest-growing disease condition. It is characterized by persistent hyperglycemia and subsequent chronic complications leading to organ dysfunction and, ultimately, the failure of target organs. Substance P (SP) is an undecapeptide that belongs to the family of tachykinin (TK) peptides. The SP-mediated activation of the neurokinin 1 receptor (NK1R) regulates many pathophysiological processes in the body. There is also a relation between the SP/NK1R system and diabetic processes. Importantly, deregulated expression of SP has been reported in diabetes and diabetes-associated chronic complications. SP can induce both diabetogenic and antidiabetogenic effects and thus affect the pathology of diabetes destructively or protectively. Here, we review the current knowledge of the functional relevance of the SP/NK1R system in diabetes pathogenesis and its exploitation for diabetes therapy. A comprehensive understanding of the role of the SP/NK1R system in diabetes is expected to shed further light on developing new therapeutic possibilities for diabetes and its associated chronic conditions.

MicroRNA-132 attenuated cardiac fibrosis in myocardial infarction-induced heart failure rats

The aim of the present study was to determine the effect of microRNA (miR)-132 on cardiac fibrosis in myocardial infarction (MI)-induced heart failure and angiotensin (Ang) II-treated cardiac fibroblasts (CFs). Experiments were carried out in Sprague-Dawley rat treatment with ligation of left coronary artery to induce heart failure, and in CFs administration of Ang II to induce fibrosis. The level of miR-132 was increased in the heart of rats with MI-induced heart failure and the Ang II-treated CFs. In MI rats, left ventricle (LV) ejection fraction, fractional shortening, the maximum of the first differentiation of LV pressure (LV +dp/dtmax) and decline (LV -dp/dtmax) and LV systolic pressure (LVSP) were reduced, and LV end-systolic diameter (LVESD), LV end-diastolic diameter (LVEDD), LV volumes in systole (LVVS) and LV volumes in diastole (LVVD) were increased, which were reversed by miR-132 agomiR but deteriorated by miR-132 antagomiR. The expression levels of collagen I, collagen III, transforming growth factor-β (TGF-β), and α-smooth muscle actin (α-SMA) were increased in the heart of rat with MI-induced heart failure and CFs administration of Ang II. These increases were inhibited by miR-132 agomiR but enhanced by miR-132 antagomiR treatment. MiR-132 inhibited PTEN expression, and attenuated PI3K/Akt signal pathway in CFs. These results indicated that the up-regulation of miR-132 improved the cardiac dysfunction, attenuated cardiac fibrosis in heart failure via inhibiting PTEN expression, and attenuating PI3K/Akt signal pathway. Up-regulation of miR-132 may be a strategy for the treatment of heart failure and cardiac fibrosis.

Kinins and nitric oxide in patients with chronic chagas disease and systemic arterial hypertension

BACKGROUND

Chronic Chagas disease (CCHD) associated with Systemic Arterial Hypertension (SAH) is frequently found in areas where the disease is endemic. The pathogenesis of patients with both pathologies (CCHD-SAH) is unsettled. Nitric Oxide (NO) and Kinins are important players in the myocardial inflammation process in experimental CCHD. No previous study has addressed this question in patients with CCHD, particularly in those with CCHD-SAH. Accordingly, this study was undertaken in an attempt to contribute to the understanding of the pathogenesis of patients with CCHD-SAH.

METHODS

Thirty-seven patients with a positive serology for Chagas disease were enrolled; 15 had CCHD alone, 22 had CCHD-SAH (abnormal ECG/Doppler echocardiogram plus a systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg on admission), and 11 had SAH alone. Thirty healthy individuals matched by age and sex served as controls. Plasma High-molecular (Hkg) and low-molecular weight (LKg) kininogens, plasma kallikrein levels (Pkal and Tcal), Kininase II, and plasma NO were measured.

RESULTS

HKg and LKg were lower in CCHD-SAH patients in comparison with other groups (P < .0001). Pkal and Tcal were higher in CCHD-SAH patients in comparison with the other groups (P< .0001). Kininase II levels were similar in SAH, CCHD, and CCHD-SAH patients, but lower in comparison with controls (P< .0001). NO levels were similar in CCHD and CCHD-SAH patients, but higher in comparison with SAH patients and controls (P > .0001).

CONCLUSION

Such findings suggest increased Kinin and NO activity in patients with CCHD-SAH, thus contributing to the understanding of the pathogenesis of this condition.

Substance P and fibrotic diseases

Substance P (SP) is an undecapeptide encoding the tachykinin 1 (TAC1) gene and belongs to the tachykinin family. SP is widely distributed in the central nervous system and the peripheral nervous system. SP is also produced by nonneuronal cells, such as inflammatory cells and endothelial cells. The biological activities of SP are mainly regulated through the high-affinity neurokinin 1 receptor (NK-1R). The SP/NK-1R system plays an important role in the molecular bases of many human pathophysiologic processes, such as pain, infectious and inflammatory diseases, and cancer. In addition, this system has been implicated in fibrotic diseases and processes such as wound healing, myocardial fibrosis, bowel fibrosis, myelofibrosis, renal fibrosis, and lung fibrosis. Recently, studies have shown that SP plays an important role in liver fibrosis and that NK-1R antagonists can inhibit the progression of fibrosis. NK-1R receptor antagonists could provide clinical solutions for fibrotic diseases. This review summarizes the structure and function of SP and its involvement in fibrotic diseases.

ISSLS Prize in Basic science 2019: Physical activity attenuates fibrotic alterations to the multifidus muscle associated with intervertebral disc degeneration

PURPOSE

Chronic low back pain causes structural remodelling and inflammation in the multifidus muscle. Collagen expression is increased in the multifidus of humans with lumbar disc degeneration. However, the extent and mechanisms underlying the increased fibrotic activity in the multifidus are unknown. Physical activity reduces local inflammation that precedes multifidus fibrosis during intervertebral disc degeneration (IDD), but its effect on amelioration of fibrosis is unknown. This study aimed to assess the development of fibrosis and its underlying genetic network during IDD and the impact of physical activity.

METHODS

Wild-type and SPARC-null mice were either sedentary or housed with a running wheel, to allow voluntary physical activity. At 12 months of age, IDD was assessed with MRI, and multifidus muscle samples were harvested from L2 to L6. In SPARC-null mice, the L1/2 and L3/4 discs had low and high levels of IDD, respectively. Thus, multifidus samples from L2 and L4 were allocated to low- and high-IDD groups compared to assess the effects of IDD and physical activity on connective tissue and fibrotic genes.

RESULTS

High IDD was associated with greater connective tissue thickness and dysregulation of collagen-III, fibronectin, CTGF, substance P, TIMP1 and TIMP2 in the multifidus muscle. Physical activity attenuated the IDD-dependent increased connective tissue thickness and reduced the expression of collagen-I, fibronectin, CTGF, substance P, MMP2 and TIMP2 in SPARC-null animals and wild-type mice. Collagen-III and TIMP1 were only reduced in wild-type animals.

CONCLUSIONS

These data reveal the fibrotic networks that promote fibrosis in the multifidus muscle during chronic IDD. Furthermore, physical activity is shown to reduce fibrosis and regulate the fibrotic gene network. These slides can be retrieved under Electronic Supplementary Material.

Substance P and patterned silk biomaterial stimulate periodontal ligament stem cells to form corneal stroma in a bioengineered three-dimensional model

Background

We aimed to generate a bioengineered multi-lamellar human corneal stroma tissue in vitro by differentiating periodontal ligament stem cells (PDLSCs) towards keratocytes on an aligned silk membrane.

Methods

Human PDLSCs were isolated and identified. The neuropeptide substance P (SP) was added in keratocyte differentiation medium (KDM) to evaluate its effect on keratocyte differentiation of PDLSCs. PDLSCs were then seeded on patterned silk membrane and cultured with KDM and SP. Cell alignment was evaluated and the expression of extracellular matrix (ECM) components of corneal stroma was detected. Finally, multi-lamellar tissue was constructed in vitro by PDLSCs seeded on patterned silk membranes, which were stacked orthogonally and stimulated by KDM supplemented with SP for 18 days. Sections were prepared and subsequently stained with hematoxylin and eosin or antibodies for immunofluorescence observation of human corneal stroma-related proteins.

Results

SP promoted the expression of corneal stroma-related collagens (collagen types I, III, V, and VI) during the differentiation induced by KDM. Patterned silk membrane guided cell alignment of PDLSCs, and important ECM components of the corneal stroma were shown to be deposited by the cells. The constructed multi-lamellar tissue was found to support cells growing between every two layers and expressing the main type of collagens (collagen types I and V) and proteoglycans (lumican and keratocan) of normal human corneal stroma.

Conclusions

Multi-lamellar human corneal stroma-like tissue can be constructed successfully in vitro by PDLSCs seeded on orthogonally aligned, multi-layered silk membranes with SP supplementation, which shows potential for future corneal tissue engineering.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0715-y) contains supplementary material, which is available to authorized users.

Transforming growth factor β: A potential biomarker and therapeutic target of ventricular remodeling

Transforming growth factor β (TGF-β) is a multifunctional cytokine that is synthesized by many types of cells and regulates the cell cycle. Increasing evidence has led to TGF-β receiving increased and deserved attention in recent years because it may play a potentially novel and critical role in the development and progression of myocardial fibrosis and the subsequent progress of ventricular remodeling (VR). Numerous studies have highlighted a crucial role of TGF-β in VR and suggest potential therapeutic targets of the TGF-β signaling pathways for VR. Changes in TGF-β activity may elicit anti-VR activity and may serve as a novel therapeutic target for VR therapy. This review we discusses the smad-dependent signaling pathway, such as TGF-β/Smads, TGF-β/Sirtuins, TGF-β/BMP, TGF-β/miRNAs, TGF-β/MAPK, and Smad-independent signaling pathway of TGF-β, such as TGF-β/PI3K/Akt, TGF-β/Rho/ROCK,TGF-β/Wnt/β-catenin in the cardiac fibrosis and subsequent progression of VR. Furthermore, agonists and antagonists of TGF-β as potential therapeutic targets in VR are also described.