Angiotensin III Induces JAK2/STAT3 Leading to IL-6 Production in Rat Vascular Smooth Muscle Cells

The Role of IL-6 in Neurodegenerative Disorders

"Neurodegenerative disorder" is an umbrella term for a group of fatal progressive neurological illnesses characterized by neuronal loss and inflammation. Interleukin-6 (IL-6), a pleiotropic cytokine, significantly affects the activities of nerve cells and plays a pivotal role in neuroinflammation. Furthermore, as high levels of IL-6 have been frequently observed in association with several neurodegenerative disorders, it may potentially be used as a biomarker for the progression and prognosis of these diseases. This review summarizes the production and function of IL-6 as well as its downstream signaling pathways. Moreover, we make a comprehensive review on the roles of IL-6 in neurodegenerative disorders and its potential clinical application.

Examining the Effects of Dasatinib, Sorafenib, and Nilotinib on Vascular Smooth Muscle Cells: Insights into Proliferation, Migration, and Gene Expression Dynamics

BACKGROUND

Dasatinib, nilotinib, and sorafenib are clinically proven tyrosine kinase inhibitors (TKIs) used for the treatment of leukemia and hepatocellular carcinoma. However, there is a growing concern regarding cardiotoxicity associated with their use. The impact of these TKIs on vascular smooth muscle cells (VSMCs) remains unexplored. This study aims to investigate the effects of TKIs on VSMC proliferation and migration, as well as to elucidate the underlying mechanisms involving inflammatory and apoptotic pathways.

METHODS

VSMCs were extracted from albino rats and cultured in vitro. The cells were divided into four experimental groups: control, dasatinib, sorafenib, and nilotinib. The MTT assay was employed to assess the cytotoxic effects of TKIs on VSMCs. A scratch assay was conducted to evaluate the inhibitory potential of TKIs on VSMC migration. Flow cytometry analysis was used to detect apoptotic cells. Real-Time PCR expression was utilized to determine the differential gene expression of apoptotic and inflammatory markers.

RESULTS

Dasatinib, nilotinib, and sorafenib demonstrated significant inhibitory effects on VSMC viability and migration at low concentrations (<1 µmol/L, p < 0.05). Furthermore, gene expression analysis revealed up-regulation of inflammatory biomarkers (TNF-α, IL-6, and IL-1β) and apoptotic markers (P53, BAX), along with down-regulation of the anti-apoptotic biomarker BCL-2 in response to all TKIs.

CONCLUSIONS

This study demonstrates that dasatinib, nilotinib, and sorafenib inhibit VSMC proliferation and migration, suggesting their potential to induce vascular injury and remodeling by activating inflammation and apoptosis pathways. These findings highlight the need for further investigation into the cardiotoxic effects of these TKIs and the development of strategies to mitigate their adverse vascular effects.

Quercetin inhibits angiotensin II-induced vascular smooth muscle cell proliferation and activation of JAK2/STAT3 pathway: A target based networking pharmacology approach

The rapid growth of vascular smooth muscle cells (VSMCs) represents crucial pathological changes during the development of hypertensive vascular remodeling. Although quercetin exhibits significantly therapeutic effects on antihypertension, the systematic role of quercetin and its exact mode of action in relation to the VSMCs growth and its hypertension-related networking pharmacology is not well-documented. Therefore, the effect of quercetin was investigated using networking pharmacology followed by in vitro strategies to explore its efficacy against angiotensin II (Ang II)-induced cell proliferation. Putative genes of hypertension and quercetin were collected using database mining, and their correlation was investigated. Subsequently, a network of protein-protein interactions was constructed and gene ontology (GO) analysis was performed to identify the role of important genes (including CCND1) and key signaling pathways [including cell proliferation and Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway]. We therefore further investigated the effects of quercetin in Ang II-stimulated VSMCs. This current research revealed that quercetin significantly reduced the cell confluency, cell number, and cell viability, as well as expression of proliferating cell nuclear antigen (PCNA) in Ang II-stimulated VSMCs. Mechanistic study by western blotting confirmed that quercetin treatment attenuated the activation of JAK2 and STAT3 by reducing its phosphorylation in Ang II stimulated VSMCs. Collectively, the current study revealed the inhibitory effects of quercetin on proliferation of Ang II stimulated VSMCs, by inhibiting the activation of JAK2/STAT3 signaling might be one of underlying mechanisms.

Roles of Angiotensin III in the brain and periphery

Angiotensin (Ang) III, a biologically active peptide of the renin angiotensin system (RAS) is predominantly known for its central effects on blood pressure. Our understanding of the RAS has evolved from the simplified, classical RAS, a hormonal system regulating blood pressure to a complex system affecting numerous biological processes. Ang II, the main RAS peptide has been widely studied, and its deleterious effects when overexpressed is well-documented. However, other components of the RAS such as Ang III are not well studied. This review examines the molecular and biological actions of Ang III and provides insight into Ang III's potential role in metabolic diseases.

Carbon monoxide releasing molecule-2 attenuates angiotensin II-induced IL-6/Jak2/Stat3-associated inflammation by inhibiting NADPH oxidase- and mitochondria-derived ROS in human aortic smooth muscle cells

Abdominal aortic aneurysm (AAA) is a common inflammatory vascular disease. Angiotensin II (Ang II) involves in AAA progression by promoting the proliferation and migration of vascular smooth muscle cells, the degradation of extracellular matrices, and the generation of ROS to lead to vascular inflammation. Carbon monoxide releasing molecule-2 (CORM-2) is known to exert anti-inflammatory and antioxidant activities. However, it remains unclear whether CORM-2 can suppress Ang II-induced vascular inflammation to prevent AAA progression. Therefore, this study aimed to investigate the vasoprotective effects of CORM-2 against Ang II-induced inflammatory responses of human aortic smooth muscle cells (HASMCs) and the underlying mechanisms of those effects. The results showed that Ang II induced inflammatory responses of HASMCs via NADPH oxidase- and mitochondria-derived ROS/NF-κB/IL-6/Jak2/Stat3 pathway which was attenuated by the pretreatment with CORM-2. Additionally, CORM-2 further exhibited anti-inflammatory activities in Ang II-stimulated HASMCs, as indicated by the reduction of monocyte adhesion to HASMCs and migration of HASMCs via the suppression of ICAM-1 and VCAM-1 as well as MMP-2 and MMP-9 levels, respectively. Moreover, Ang II-induced COX-2-mediated PGE₂ secretion was also inhibited by the pretreatment with CORM-2. Importantly, our data demonstrated that CORM-2 reversed Ang II-induced IL-6 overexpression dependent on Nrf2 activation and HO-1 expression. Taken together, the present study indicates that CORM-2-induced Nrf2/HO-1 alleviates IL-6/Jak2/Stat3-mediated inflammatory responses to Ang II by inhibiting NADPH oxidase- and mitochondria-derived ROS, suggesting that CORM-2 is a promising pharmacologic candidate to reverse the pathological changes involved in the inflammation of vessel wall for the prevention and treatment of AAA.

Effect of profilin-1 on the asymmetric dimethylarginine-induced vascular lesion-associated hypertension

Previous studies have demonstrated that the levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, are strongly associated with hypertension, diabetes, and cardiovascular diseases. Profilin-1, an actin-binding protein, has been documented to be involved in endothelial injury and in the proliferation of vascular smooth muscle cells resulting from hypertension. However, the role of profilin-1 in ADMA-induced vascular injury in hypertension remains largely unknown. Forty healthy subjects and forty-two matched patients with essential hypertension were enrolled, and the related indexes of vascular injury in plasma were detected. Rat aortic smooth muscle cells (RASMCs) were treated with different concentrations of ADMA for different periods of time and transfected with profilin-1 small hairpin RNA to interrupt the expression of profilin-1. To determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway, RASMCs were pretreated with AG490 or rapamycin. The expression of profilin-1 was tested using real-time polymerase chain reaction (PCR) and western blot analysis. Cell proliferation was measured by flow cytometry and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazoliumbromide assays. Compared with healthy subjects, the levels of ADMA and profilin-1 were markedly elevated in hypertensive individuals, while the levels of NO were significantly decreased (p < 0.05). In vitro, studies showed ADMA-induced profilin-1 expression in a concentration- and time-dependent manner in RASMCs (p < 0.05), concomitantly with promoting the proliferation of RASMCs. Furthermore, ADMA-mediated proliferation of RASMCs and upregulation expression of profilin-1 were inhibited by blockade of the JAK2/STAT3 pathway or knockdown of profilin-1. Profilin-1 implicated in the ADMA-mediated vascular lesions in hypertension.

Chronic Intermittent Hypobaric Hypoxia Decreases High Blood Pressure by Stabilizing the Vascular Renin-Angiotensin System in Spontaneously Hypertensive Rats

Background and Aims

Previous studies have demonstrated the anti-hypertensive effect of chronic intermittent hypobaric hypoxia (CIHH) in hypertensive rats. The present study investigated the anti-hypertensive effect of CIHH in spontaneously hypertensive rats (SHR) and the role of the renin-angiotensin system (RAS) in anti-hypertensive effect of CIHH.

Methods

Fifteen-week-old male SHR and WKY rats were divided into four groups: the SHR without CIHH treatment (SHR-CON), the SHR with CIHH treatment (SHR-CIHH), the WKY without CIHH treatment (WKY-CON), and the WKY with CIHH treatment (WKY-CIHH) groups. The SHR-CIHH and WKY-CIHH rats underwent 35-days of hypobaric hypoxia simulating an altitude of 4,000 m, 5 h per day. Arterial blood pressure and heart rate were recorded by biotelemetry, and angiotensin (Ang) II, Ang1–7, interleukin (IL)-6, tumor necrosis factor-alpha (TNF)-α, and IL-10 in serum and the mesenteric arteries were measured by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, respectively. The microvessel tension recording technique was used to determine the contraction and relaxation of the mesenteric arteries. Hematoxylin and eosin and Masson’s staining were used to observe vascular morphology and fibrosis. Western blot was employed to detect the expression of the angiotensin-converting enzyme (ACE), ACE2, AT1, and Mas proteins in the mesenteric artery.

Results

The biotelemetry result showed that CIHH decreased arterial blood pressure in SHR for 3–4 weeks (P < 0.01). The ELISA and immunohistochemistry results showed that CIHH decreased Ang II, but increased Ang1–7 in serum and the mesenteric arteries of SHR. In the CIHH-treated SHR, IL-6 and TNF-α decreased in serum and the mesenteric arteries, and IL-10 increased in serum (P < 0.05–0.01). The microvessel tension results revealed that CIHH inhibited vascular contraction with decreased Ang1–7 in the mesenteric arteries of SHR (P < 0.05–0.01). The staining results revealed that CIHH significantly improved vascular remodeling and fibrosis in SHR. The western blot results demonstrated that CIHH upregulated expression of the ACE2 and Mas proteins, and downregulated expression of the ACE and AT1 proteins (P < 0.05–0.01).

Conclusion

CIHH decreased high blood pressure in SHR, possibly by inhibiting RAS activity, downregulating the ACE-Ang II-AT1 axis and upregulating the ACE2-(Ang1-7)-Mas axis, which resulted in antagonized vascular remodeling and fibrosis, reduced inflammation, and enhanced vascular relaxation.

Role of the central renin‑angiotensin system in hypertension (Review)

Present in more than one billion adults, hypertension is the most significant modifiable risk factor for mortality resulting from cardiovascular disease. Although its pathogenesis is not yet fully understood, the disruption of the renin-angiotensin system (RAS), consisting of the systemic and brain RAS, has been recognized as one of the primary reasons for several types of hypertension. Therefore, acquiring sound knowledge of the basic science of RAS and the under- lying mechanisms of the signaling pathways associated with RAS may facilitate the discovery of novel therapeutic targets with which to promote the management of patients with cardiovascular and kidney disease. In total, 4 types of angiotensin II receptors have been identified (AT1R-AT4R), of which AT1R plays the most important role in vasoconstriction and has been most extensively studied. It has been found in several regions of the brain, and its distribution is highly associated with that of angiotensin-like immunoreactivity in nerve terminals. The effect of AT1R involves the activation of multiple media and signaling pathways, among which the most important signaling pathways are considered to be AT1R/JAK/STAT and Ras/Raf/MAPK pathways. In addition, the regulation of the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and cyclic AMP response element-binding (CREB) pathways is also closely related to the effect of ATR1. Their mechanisms of action are related to pro-inflammatory and sympathetic excitatory effects. Central AT1R is involved in almost all types of hypertension, including spontaneous hypertension, salt-sensitive hypertension, obesity-induced hypertension, renovascular hypertension, diabetic hypertension, L-NAME-induced hypertension, stress-induced hypertension, angiotensin II-induced hyper- tension and aldosterone-induced hypertension. There are 2 types of central AT1R blockade, acute blockade and chronic blockade. The latter can be achieved by chemical blockade or genetic engineering. The present review article aimed to high- light the prevalence, functions, interactions and modulation means of central AT-1R in an effort to assist in the treatment of several pathological conditions. The identification of angiotensin-derived peptides and the development of AT-2R agonists may provide a wider perspective on RAS, as well as novel therapeutic strategies.

Chromosome 2 Fragment Substitutions in Dahl Salt-Sensitive Rats and RNA Sequencing Identified Enpep and Hs2st1 as Vascular Inflammatory Modulators

Chromosome 2 introgression from normotensive Brown Norway (BN) rats into hypertensive Dahl salt-sensitive (SS) background (SS-chromosome 2^BN/Mcwi; consomic S2^B) reduced blood pressure and vascular inflammation under a normal-salt diet (NSD). We hypothesized that BN chromosome 2 contains anti-inflammatory genes that could reduce blood pressure and vascular inflammation in rats fed NSD or high-salt diet (HSD). Four- to 6-week old male SS and congenic rats containing the BN chromosome 2 distal portion (SS.BN-[rs13453786-rs66377062]/Aek; S2^Ba) and middle segment (SS.BN-[rs106982173-rs65057186]/Aek; S2^Bb) were fed NSD or HSD (4% NaCl) up to age 12 to 13 weeks. Systolic blood pressure determined by telemetry was higher in SS rats fed HSD versus NSD. Systolic blood pressure was lower in both congenic rats than in SS under NSD, but similar under HSD versus SS. Reactive oxygen species generation using dihydroethidium staining, expression of vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1, and immune cell infiltration by immunofluorescence demonstrated that S2^Ba rats present less inflammation under NSD and more under HSD versus SS rats. RNA sequencing and reverse transcription-quantitative PCR identified 2 differentially expressed genes encoded within BN chromosome 2 distal portion that could act as regulators of vascular inflammation. These were downregulated glutamyl aminopeptidase (Enpep) that was anti-inflammatory under NSD and upregulated heparan sulfate 2-O-sulfotransferase 1 (Hs2st1) that was proinflammatory under HSD. In conclusion, 2 differentially expressed genes encoded within introgressed BN chromosome 2 distal fragment were identified: Enpep associated with reduced vascular inflammation under NSD, and Hs2st1, associated with increased vascular inflammation under HSD.

Role of the JAK2/STAT3 pathway in angiotensin II-induced enhanced expression of Giα proteins and hyperproliferation of aortic vascular smooth muscle cells

We earlier showed that angiotensin (Ang) II-induced overexpression of Giα proteins contributes to the hyperproliferation of vascular smooth muscle cells (VSMC). In addition, the implication of the JAK2/STAT3 pathway in Ang II-induced hyperproliferation of VSMC has also been reported. However, the role of the JAK2/STAT3 pathway in Ang II-induced overexpression of Giα proteins and hyperproliferation of VSMC remains unexplored. In the present study, we show that inhibition or knockdown of the JAK2/STAT3 pathway by a specific inhibitor "cucurbitacin I" (CuI) or siRNAs attenuated Ang II-induced overexpression of Giα proteins and hyperproliferation of VSMC. In addition, the enhanced expression of cell cycle proteins induced by Ang II was also attenuated by CuI. Furthermore, Ang II-induced enhanced production of the superoxide anion (O₂ ^-), H₂O₂, and NADPH oxidase activity, as well as the enhanced expression of NADPH oxidase subunits implicated in enhanced expression of Giα proteins and hyperproliferation, were also attenuated by inhibition of the JAK2/STAT3 pathway. On the other hand, Ang II-induced inhibition and augmentation of the levels of nitric oxide and peroxynitrite, respectively, in VSMC were restored to control levels by CuI. In summary, our results demonstrate that Ang II through the JAK2/STAT3 pathway increases nitroxidative stress, which contributes to the overexpression of Giα proteins and cell cycle proteins and the hyperproliferation of VSMC.

Intrarenal Renin Angiotensin System Imbalance During Postnatal Life Is Associated With Increased Microvascular Density in the Mature Kidney

Environmental stress during early life is an important factor that affects the postnatal renal development. We have previously shown that male rats exposed to maternal separation (MatSep), a model of early life stress, are normotensive but display a sex-specific reduced renal function and exacerbated angiotensin II (AngII)-mediated vascular responses as adults. Since optimal AngII levels during postnatal life are required for normal maturation of the kidney, this study was designed to investigate both short- and long-term effect of MatSep on (1) the renal vascular architecture and function, (2) the intrarenal renin-angiotensin system (RAS) components status, and (3) the genome-wide expression of genes in isolated renal vasculature. Renal tissue and plasma were collected from male rats at different postnatal days (P) for intrarenal RAS components mRNA and protein expression measurements at P2, 6, 10, 14, 21, and 90 and microCT analysis at P21 and 90. Although with similar body weight and renal mass trajectories from P2 to P90, MatSep rats displayed decreased renal filtration capacity at P90, while increased microvascular density at both P21 and P90 (p < 0.05). MatSep increased renal expression of renin, and angiotensin type 1 (AT1) and type 2 (AT2) receptors (p < 0.05), but reduced ACE2 mRNA expression and activity from P2-14 compared to controls. However, intrarenal levels of AngII peptide were reduced (p < 0.05) possible due to the increased degradation to AngIII by aminopeptidase A. In isolated renal vasculature from neonates, Enriched Biological Pathways functional clusters (EBPfc) from genes changed by MatSep reported to modulate extracellular structure organization, inflammation, and pro-angiogenic transcription factors. Our data suggest that male neonates exposed to MatSep could display permanent changes in the renal microvascular architecture in response to intrarenal RAS imbalance in the context of the atypical upregulation of angiogenic factors.