Transforming growth factor beta signaling, vascular remodeling, and hypertension

Association of THBS1 genetic variants and mRNA expression with the risks of ischemic stroke and long-term death after stroke

Background

Thrombospondin-1 (THBS1) derived from platelets and acted as a critical mediator of hemostasis promoting platelet activation in thrombus formation. The biological connection of genetic variants and mRNA expression of THBS1 with ischemic stroke (IS) warrants further validation with population-based evidence.

Objective

To evaluate the association of single nucleotide polymorphisms (SNPs) and mRNA expression of THBS1 with the risks of IS and long-term death after stroke.

Methods

A case-control study consisted of 4,584 IS patients recruited from five hospitals in Jiangsu, China, and 4,663 age-gender-matched controls free of IS. A cohort study enrolled 4,098 participants free of stroke and lasted from 2009 to 2022. Early collected 3158 IS patients aged between 35 and 80 years were followed up an average of 5.86-year to follow up their long-term death outcomes. Two tagSNPs of the THBS1 gene, rs2236471 and rs3743125, were genotyped in all subjects and THBS1 mRNA expression of peripheral leukocyte was measured using RT-qPCR in 314 IS cases and 314 controls.

Results

There is no significant difference in genotype and haplotype frequencies of rs2236741 and rs3743125 between IS cases and controls (all P > 0.05). Furthermore, the cohort studies did not observe significant associations between THBS1 variants and the risk of IS incidence or long-term death after IS (all P > 0.05). The THBS1 mRNA expression level (2^–ΔΔCT) in IS cases was approximately equal to that in controls (1.01 vs. 0.99, P = 0.833). In addition, THBS1 mRNA expression had no significant association with all-cause death, stroke death, and IS death of IS patients (all P > 0.05).

Conclusion

Therefore, our study suggested that there is no significant association of THBS1 polymorphisms and mRNA expression level with the risk of IS and long-term death after IS.

Isoliquiritigenin ameliorates advanced glycation end-products toxicity on renal proximal tubular epithelial cells

Diabetic nephropathy is a serious chronic complication affecting at least 25% of diabetic patients. Hyperglycemia associated advanced glycation end-products (AGEs) increase tubular epithelial-myofibroblast transdifferentiation (TEMT) and extracellular matrix synthesis and thereby causes renal fibrosis. The chalcone isoliquiritigenin, found in many herbs of Glycyrrhiza family, is known for potential health-promoting effects. However, their effects on AGE-associated renal proximal tubular fibrosis are not known yet. In this study, the effect of isoliquiritigenin on AGE-induced renal proximal tubular fibrosis was determined in cultured HK-2 cell line. The results show that 200 μg/mL of AGE-induced TEMT and the formed myofibroblasts synthesized collagen to increase extracellular matrix formation thereby lead to renal tubular fibrosis. However, treatment with 200 nM of isoliquiritigenin considerably inhibited the TEMT and suppressed the TGFβ/STAT3 mechanism to inhibit collagen secretion. Therefore, isoliquiritigenin effectively suppressed AGE-induced renal tubular fibrosis.

Worsening baroreflex sensitivity on progression to type 2 diabetes: localized vs. systemic inflammation and role of antidiabetic therapy

Cardiac autonomic neuropathy (CAN) is an early cardiovascular manifestation of type 2 diabetes (T2D) that constitutes an independent risk factor for cardiovascular mortality and morbidity. Nevertheless, its underlying pathophysiology remains poorly understood. We recently showed that localized perivascular adipose tissue (PVAT) inflammation underlies the incidence of parasympathetic CAN in prediabetes. Here, we extend our investigation to provide a mechanistic framework for the evolution of autonomic impairment as the metabolic insult worsens. Early metabolic dysfunction was induced in rats fed a mild hypercaloric diet. Two low-dose streptozotocin injections were used to evoke a state of late decompensated T2D. Cardiac autonomic function was assessed by invasive measurement of baroreflex sensitivity using the vasoactive method. Progression into T2D was associated with aggravation of CAN to include both sympathetic and parasympathetic arms. Unlike prediabetic rats, T2D rats showed markers of brainstem neuronal injury and inflammation as well as increased serum levels of IL-1β. Experiments on PC12 cells differentiated into sympathetic-like neurons demonstrated that brainstem injury observed in T2D rats resulted from exposure to possible proinflammatory mediators in rat serum rather than a direct effect of the altered metabolic profile. CAN and the associated cardiovascular damage in T2D only responded to combined treatment with insulin to manage hyperglycemia in addition to a nonhypoglycemic dose of metformin or pioglitazone providing an anti-inflammatory effect, coincident with the effect of these combinations on serum IL-1β. Our present results indicate that CAN worsening upon progression to T2D involves brainstem inflammatory changes likely triggered by systemic inflammation.

TGF-β Signaling: A Therapeutic Target to Reinstate Regenerative Plasticity in Vascular Dementia?

Vascular dementia (VaD) is the second leading form of memory loss after Alzheimer's disease (AD). Currently, there is no cure available. The etiology, pathophysiology and clinical manifestations of VaD are extremely heterogeneous, but the impaired cerebral blood flow (CBF) represents a common denominator of VaD. The latter might be the result of atherosclerosis, amyloid angiopathy, microbleeding and micro-strokes, together causing blood-brain barrier (BBB) dysfunction and vessel leakage, collectively originating from the consequence of hypertension, one of the main risk factors for VaD. At the histopathological level, VaD displays abnormal vascular remodeling, endothelial cell death, string vessel formation, pericyte responses, fibrosis, astrogliosis, sclerosis, microglia activation, neuroinflammation, demyelination, white matter lesions, deprivation of synapses and neuronal loss. The transforming growth factor (TGF) β has been identified as one of the key molecular factors involved in the aforementioned various pathological aspects. Thus, targeting TGF-β signaling in the brain might be a promising therapeutic strategy to mitigate vascular pathology and improve cognitive functions in patients with VaD. This review revisits the recent understanding of the role of TGF-β in VaD and associated pathological hallmarks. It further explores the potential to modulate certain aspects of VaD pathology by targeting TGF-β signaling.

Qingxuan Jiangya Decoction () Prevents Blood Pressure Elevation and Ameliorates Vascular Structural Remodeling via Modulating TGF-β 1/Smad Pathway in Spontaneously Hypertensive Rats

OBJECTIVE

To elevate the effects of Qingxuan Jiangya Decoction (, QXJYD) on hypertension and vascular structural remodeling (VSR) in spontaneously hypertensive rats (SHRs), and investigate the underlying mechanisms.

METHODS

SHRs (n=8) were given intra-gastric administration with 60 mg/kg of QXJYD or saline, daily for 8 weeks, while rats in SHR-control (n=8) and WKY (n=8) groups were received equal volumes of saline solution. Systolic blood pressures (SBP), diastolic blood pressures (DBP) and mean blood pressures (MBP) were measured once a week. The levels of angiotensin II (Ang II), endothelin 1 (ET-1) and plasma renin activity (PRA) were tested by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay, respectively. The effect of QXJYD on VSR was determined by examining the media thickness and the ex vivo contractility of thoracic aortic. The proliferation and fibrosis of vascular smooth muscle cells (VSMCs) were examined via immunohistochemical (IHC) staining for proliferating cell nuclear antigen (PCNA), collagen I and collagen III, respectively. The mRNA and protein expressions of transforming growth factor β 1 (TGF-β 1), Smad3 and phosphorylation of Smad3 in thoracic aorta tissues were determined by real-time polymerase chain reaction (PCR) and Western blot assay, respectively.

RESULTS

QXJYD treatment led to a significant decrease of the elevation of blood pressure in SHRs and reduced the levels of Ang II, ET-1 and PRA in the serum (P<0.05). In addition, QXJYD treatment remarkably ameliorated VSR and vascular function in SHRs. Moreover, QXJYD inhibited VSMC proliferation and fibrosis by suppressing the expression of PCNA, collagen I and collagen III in thoracic aortic. Furthermore, QXJYD inhibited the expression of TGF-β 1, Smad3 and the phosphorylation of Smad3, respectively (P<0.05).

CONCLUSION

QXJYD reversed VSR by inhibiting VSMC proliferation and collagen deposition via regulation of TGF-β 1/Smad signaling pathway, which may, in part, illuminate its anti-hypertensive activities.

Amelioration of perivascular adipose inflammation reverses vascular dysfunction in a model of nonobese prediabetic metabolic challenge: potential role of antidiabetic drugs

The onset of vascular impairment precedes that of diagnostic hyperglycemia in diabetic patients suggesting a vascular insult early in the course of metabolic dysfunction without a well-defined mechanism. Mounting evidence implicates adipose inflammation in the pathogenesis of insulin resistance and diabetes. It is not certain whether amelioration of adipose inflammation is sufficient to preclude vascular dysfunction in early stages of metabolic disease. Recent findings suggest that antidiabetic drugs, metformin, and pioglitazone, improve vascular function in prediabetic patients, without an indication if this protective effect is mediated by reduction of adipose inflammation. Here, we used a prediabetic rat model with delayed development of hyperglycemia to study the effect of metformin or pioglitazone on adipose inflammation and vascular function. At the end of the metabolic challenge, these rats were neither obese, hypertensive, nor hyperglycemic. However, they showed increased pressor responses to phenylephrine and augmented aortic and mesenteric contraction. Vascular tissues from prediabetic rats showed increased Rho-associated kinase activity causing enhanced calcium sensitization. An elevated level of reactive oxygen species was seen in aortic tissues together with increased Transforming growth factor β1 and Interleukin-1β expression. Although, no signs of systemic inflammation were detected, perivascular adipose inflammation was observed. Adipocyte hypertrophy, increased macrophage infiltration, and elevated Transforming growth factor β1 and Interleukin-1β mRNA levels were seen. Two-week treatment with metformin or pioglitazone or switching to normal chow ameliorated adipose inflammation and vascular dysfunction. Localized perivascular adipose inflammation is sufficient to trigger vascular dysfunction early in the course of diabetes. Interfering with this inflammatory process reverses this early abnormality.

Sauchinone inhibits angiotensin II-induced proliferation and migration of vascular smooth muscle cells

Hypertension is a common type of cardiovascular disease that remains a major cause of death in the world. Vascular remodelling is an important complication of hypertension, and vascular smooth muscle cells (VSMCs) play a major role in vascular remodelling. Sauchinone is one of the active lignins which has been found to possess vascular protective effects. However, the functional role of sauchinone in hypertension has not been investigated. The aim of this study was to evaluate the role of sauchinone in the angiotensin II (Ang II)-induced vascular remodelling model in VSMCs. The results showed that treatment of sauchinone inhibited Ang II-induced VSMCs proliferation and migration in VSMCs. Sauchinone treatment suppressed the reactive oxygen species (ROS) production and NADPH oxidase (NOX) activity in Ang II-induced VSMCs. The inhibitory effects of Ang II on expressions of VSMCs phenotype markers including α-smooth muscle actin (α-SMA), calponin, osteopontin were mitigated by sauchinone treatment. Furthermore, sauchinone inhibited Ang II-induced over-activation of TGF-β1/Smad3 signalling pathway in VSMCs. Taken together, this study identified sauchinone as a potential agent for preventing vascular remodelling in hypertension.

ALA/LA ameliorates glucose toxicity on HK-2 cells by attenuating oxidative stress and apoptosis through the ROS/p38/TGF-β1 pathway

BACKGROUND

Growing evidence indicates that oxidative stress (OS) plays a pivotal role in Diabetic nephropathy (DN). In a previous study we demonstrated that ALA/LA protected HK-2 cells against high glucose-induced cytotoxicity. So we aimed to establish the glucose injury model of HK-2 cells and investigate the beneficial effects of ALA/LA on high glucose-induced excessive production of TGF-β1 and the possible mechanisms mediating the effects.

METHODS

The expression of OS markers in high glucose-induced HK-2 cells treated with ALA/LA., including the antioxidant enzymes and reactive oxygen species (ROS) production, as well as the apoptosis rate were assayed by ELISA and flow cytometry. The p38/transforming growth factor β1 (TGF-β1) signal pathway were measured by real-time RT-PCR and western blot.

RESULTS

The modeling condition of glucose toxicity on HK-2 cells was at the glucose concentration of 40.9 mM. ALA/LA can significantly increase the activities of antioxidant enzymes and decrease ROS production stimulated by high glucose. The study also found that ALA/LA caused a decrease in the apoptosis rate and TGF-β1 level of HK-2 cells under high glucose stress through the ROS/p38 pathway.

CONCLUSIONS

ALA/LA exerts protective effects in vitro through inhibition of ROS generation, down regulation of the activation of the p38MAPK pathway and the expression of TGF-β1 in HK-2 cells.

Evidence of selection as a cause for racial disparities in fibroproliferative disease

Fibroproliferative diseases are common complex traits featuring scarring and overgrowth of connective tissue which vary widely in presentation because they affect many organ systems. Most fibroproliferative diseases are more prevalent in African-derived populations than in European populations, leading to pronounced health disparities. It is hypothesized that the increased prevalence of these diseases in African-derived populations is due to selection for pro-fibrotic alleles that are protective against helminth infections. We constructed a genetic risk score (GRS) of fibroproliferative disease risk-increasing alleles using 147 linkage disequilibrium-pruned variants identified through genome-wide association studies of seven fibroproliferative diseases with large African-European prevalence disparities. A comparison of the fibroproliferative disease GRS between 1000 Genomes Phase 3 populations detected a higher mean GRS in AFR (mean = 148 risk alleles) than EUR (mean = 136 risk alleles; T-test p-value = 1.75x10^-123). To test whether differences in GRS burden are systematic and may be due to selection, we employed the quantitative trait loci (QTL) sign test. The QTL sign test result indicates that population differences in risk-increasing allele burdens at these fibroproliferative disease variants are systematic and support a model featuring selective pressure (p-value = 0.011). These observations were replicated in an independent sample and were more statistically significant (T-test p-value = 7.26x10^-237, sign test p-value = 0.015). This evidence supports the role of selective pressure acting to increase frequency of fibroproliferative alleles in populations of African relative to European ancestry populations.

Elastin microfibril interface-located protein 1, transforming growth factor beta, and implications on cardiovascular complications

Elastin microfibril interface-located protein 1 (EMILIN1), a glycoprotein, is associated with elastin in the extracellular matrix (ECM) of arteries, lymph vasculature, and other tissues. EMILIN1 particularly has a niche role in elastin fiber biogenesis (elastogenesis) by aiding with the fusion of elastin fibers, rendering them more ordered. In addition to elastogenesis, EMILIN1 has been shown to have roles in maintenance of vascular cell morphology, smooth muscle cell adhesion to elastic fibers, and transforming growth factor (TGFβ) regulation, by inhibiting TGFβ activation via blocking the proteolytic production of the latency-associated peptide/active TGFβ complex. The increased TGFβ signaling induced during EMILIN1 deficiency alters TGFβ activity, resulting in vascular smooth muscle cell growth and vascular remodeling. The increasing systemic blood pressure associated with TGFβ signaling may be closely linked to the activity of other mediators that affect cardiovascular homeostasis, such as angiotensin II. The increase in prevalence of hypertension and other cardiovascular diseases in other disease states likely involve a complex activation of TGFβ signaling and ECM dysfunction. Thus, the interaction of TGFβ and ECM components appears to be integrative involving both structural alterations to vessels through EMILIN1 and changes in TGFβ signaling processes. This review summarizes the current knowledge on the EMILIN1-TGFβ relationship; the specific roles of EMILIN1 and TGFβ in blood pressure regulation, their synergistic interaction, and in particular the role of TGFβ (in conjunction with ECM proteins) in other disease states altering cardiovascular homeostasis.

Transforming growth factor-β1 (C509T, G800A, and T869C) gene polymorphisms and risk of ischemic stroke in North Indian population: A hospital-based case-control study

Background:

Transforming growth factor-beta 1 (TGF-β1) is a multifunctional pleiotropic cytokine involved in inflammation and pathogenesis of cerebrovascular diseases. There is limited information on the association between variations within the TGF-β1 gene polymorphisms and risk of ischemic stroke (IS). The aim of this study was to investigate the association of the TGF-β1 gene (C509T, G800A, and T869C) polymorphisms, and their haplotypes with the risk of IS in North Indian population.

Methods:

A total of 250 IS patients and 250 age- and sex-matched controls were studied. IS was classified using the Trial of Org 10172 in Acute Stroke Treatment classification. Conditional logistic regression analysis was used to calculate the strength of association between TGF-β1 gene polymorphisms and risk of IS. Genotyping was performed using SNaPshot method.

Results:

Hypertension, diabetes, dyslipidemia, alcohol, smoking, family history of stroke, sedentary lifestyle, and low socioeconomic status were found to be associated with the risk of IS. The distribution of C509T, G800A and T869C genotypes was consistent with Hardy-Weinberg Equilibrium in the IS and control groups. Adjusted conditional logistic regression analysis showed a significant association of TGF-β1 C509T (odds ratio [OR], 2.1; 95% CI; 1.2–3.8; P = 0.006), G800A (OR, 4.4; 95% CI; 2.1–9.3; P < 0.001) and T869C (OR, 2.6; 95% CI; 1.5–4.5; P = 0.001) with the risk of IS under dominant model. Haplotype analysis showed that C509-A800-T869 and T509-G800-C869 haplotypes were significantly associated with the increased risk of IS. C509T and T869C were in strong linkage disequilibrium (D' =0.51, r² = 0.23).

Conclusion:

Our results suggest that TGF-β1 polymorphisms and their haplotypes are significantly associated with the risk of IS in North Indian population.

Acetyl-11-Keto-β-Boswellic Acid Attenuates Prooxidant and Profibrotic Mechanisms Involving Transforming Growth Factor-β1, and Improves Vascular Remodeling in Spontaneously Hypertensive Rats

Vascular remodeling is an important complication of hypertension with oxidative stress-related profibrotic pathways involved. The transforming growth factor β1 (TGF-β1) has been shown to be a potential target of vasoprotection, and has multiple roles in vascular remodeling. Acetyl-11-Keto-β-Boswellic Acid (AKBA) is one of the active principles of Boswellic acids, and shows antioxidant activity in many diseases. The study is to determine effects of AKBA on systemic oxidative stress of hypertension and vascular remodeling. In the experiments, spontaneously hypertensive rats (SHR) were used. And in vitro, fibroblast was pretreated with AKBA before Ang II stimuli. In the results, treatment of AKBA markedly reduced oxidative stress, and decreased vascular remodeling by restoring vascular wall parameters and improving vascular reactivity. AKBA dramatically reduced TGF-β1 and Smad3 expression, as shown in immunofluorescence and immunohistochemistry. In cultured fibroblast, AKBA decreased intracellular ROS levels. Cell viability and proliferation, as well as migration were inhibited by AKBA. Additionally, treatment of AKBA significantly decreased TGF-β1 secretion in culture supernatant. Expression of TGF-β1, Smad3, P-Smad3 and Smad7 were also decreased by AKBA in fibroblast. In conclusion, AKBA is able to attenuate oxidative stress and profibrotic mechanisms, and improve vascular remodeling in hypertension through TGF-β1/Smad3 pathway.

Protective effect of L-glutamine against diabetes-induced nephropathy in experimental animal: Role of KIM-1, NGAL, TGF-β1, and collagen-1

Diabetic nephropathy is a serious microvascular complication and one of the main causes of end-stage renal disease. L-Glutamine (LG) is naturally occurring amino acids with antidiabetic and antioxidant potential. The aim of present investigation was to evaluate the potential of LG against streptozotocin (STZ)-induced diabetic nephropathy (DN) in laboratory rats. DN was induced in male Wistar rats (200-220 g) by intraperitoneal administration of STZ (55 mg/kg). Animals were treated orally with either distilled water (10 mg/kg) or LG (250, 500, and 1000 mg/kg) or Sitagliptin (5 mg/kg). Various biochemical, molecular, and histological (hematoxylin-eosin and Masson's trichrome stain) parameters were assessed. Administration of LG (500 and 1000 mg/kg) significantly inhibited (p < .05) STZ-induced alterations in serum and urine biochemistry (urine creatinine, uric acid, albumin, and BUN). It also significantly increased creatinine clearance rate. STZ induced increase in renal oxidonitrosative stress was significantly decreased (p < .05) by LG (500 and 1000 mg/kg) treatment. Upregulated renal KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expression after STZ administration was significantly inhibited (p < .05) by LG (500 and 1000 mg/kg) treatment. Correlation analysis also revealed that antidiabetic potential of LG attenuates STZ-induced elevated renal KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expression. Histopathological alteration induced by STZ in renal tissue was ameliorated by LG treatment. In conclusion, results of present investigation suggest that treatment with LG ameliorated STZ-induced DN via the inhibition of oxidonitrosative stress as well as downregulation of KIM-1, NGAL, TGF-β1, and collagen-1 mRNA expressions.

Genetic Considerations in Pediatric Chronic Kidney Disease

Chronic kidney disease (CKD) in children is an irreversible process that, in some cases, may lead to end-stage renal disease. The majority of children with CKD have a congenital disorder of the kidney or urological tract arising from birth. There is strong evidence for both a genetic and epigenetic component to progression of CKD. Utilization of gene-mapping strategies, ranging from genome-wide association studies to single-nucleotide polymorphism analysis, serves to identify potential genetic variants that may lend to disease variation. Genome-wide association studies evaluating population-based data have identified different loci associated with CKD progression. Analysis of single-nucleotide polymorphisms on an individual level suggests that secondary systemic sequelae of CKD are closely related to dysfunction of the cardiovascular-inflammatory axis and may lead to advanced cardiovascular disease through abnormal vascular calcification and activation of the renin-angiotensin system. Similarly, genetic variants affecting cytokine control, fibrosis, and parenchymal development may modulate CKD through development and acceleration of renal interstitial fibrosis. Epigenetic studies evaluate modification of the genome through DNA methylation, histone modification, or RNA interference, which may be directly influenced by external or environmental factors directing genomic expression. Lastly, improved understanding of the genetic and epigenetic contribution to CKD progression may allow providers to identify a population at accelerated risk for disease progression and apply novel therapies targeted at the genetic mechanism of disease.

Curcumin protects against lipopolysaccharide-induced vasoconstriction dysfunction via inhibition of thrombospondin-1 and transforming growth factor-β1

Sepsis is a complex syndrome characterized by the development of progressive dysfunction in multiple organs. The aim of the present study was to investigate the protective effect of curcumin against lipopolysaccharide (LPS)-induced vasoconstrictive dysfunction, and to investigate the possible underlying mechanism. Male Sprague-Dawley rats were randomly divided into the following groups: Control, sepsis and curcumin. A sepsis model was established by an intraperitoneal (i.p.) injection of 5 mg/kg LPS. Thoracic aortic rings obtained from the rats were mounted in an organ bath and the vasoconstriction of the rings was recorded. In addition, the serum E-selectin levels were determined by an enzyme-linked immunosorbent assay. The expression levels of thrombospondin (TSP)-1 and transforming growth factor (TGF)-β1 in the aortic tissue were detected by immunohistochemistry. Vasoconstriction of the aortic rings was found to significantly decrease in the sepsis rats when compared with the control group. However, curcumin (10 or 20 mg/kg, i.p.) prevented the vasoconstrictive dysfunction induced by LPS. The serum level of E-selectin and the expression levels of TSP-1 and TGF-β1 significantly increased in the sepsis rats when compared with the control group rats; however, the levels decreased significantly following treatment with curcumin (10 or 20 mg/kg). Furthermore, hematoxylin and eosin staining revealed that curcumin alleviated the LPS-induced damage in the aortic tunica intima and tunica media. Therefore, the results indicated that curcumin alleviates LPS-induced vasoconstrictive dysfunction in the thoracic aorta of rats. In addition, the inhibition of TSP-1 and TGF-β1 expression may be involved in the mechanism underlying this protective effect.

Blood pressure homeostasis is maintained by a P311-TGF-β axis

P311 is an 8-kDa intracellular protein that is highly conserved across species and is expressed in the nervous system as well as in vascular and visceral smooth muscle cells. P311-null (P311-/-) mice display learning and memory defects, but alterations in their vasculature have not been previously described. Here we report that P311-/- mice are markedly hypotensive with accompanying defects in vascular tone and VSMC contractility. Functional abnormalities in P311-/- mice resulted from decreased total and active levels of TGF-β1, TGF-β2, and TGF-β3 that arise as a specific consequence of decreased translation. Vascular hypofunctionality was fully rescued in vitro and in vivo by exogenous TGF-β1-TGF-β3. Conversely, P311-transgenic (P311(TG)) mice had elevated levels of TGF-β1-TGF-β3 and subsequent hypertension. Consistent with findings attained in mouse models, arteries recovered from hypertensive human patients displayed increased P311 expression. Thus, we identified P311 as the first protein known to modulate TGF-β translation and the first pan-regulator of TGF-β expression under steady-state conditions. Together, our findings point to P311 as a critical blood pressure regulator and establish a potential link between P311 expression and the development of hypertensive disease.

The haplotype of the TGFβ1 gene associated with cerebral infarction in Chinese

BACKGROUND

Transforming growth factor beta1 (TGFβ1) is a multifunctional cytokine involved in inflammation and pathogenesis of atherosclerosis. The aim of the present study was to investigate the relationship between human TGFβ1 gene +869T>C (rs1800470), -509C>T (rs1800469) single nucleotide polymorphisms (SNPs) and haplotypes and cerebral infarction (CI) in a Chinese population.

METHODS

The genetic association study was performed in 450 Chinese patients (306 male and 144 female) with CI and 450 control subjects (326 male and 124 female). TGFβ1 gene +869T>C and -509C>T polymorphisms were identified with amplification refractory mutation system polymerase chain reaction and DNA sequencing method.

RESULTS

The individual SNPs analysis showed the +869T and -509C in an additive model (+869T vs +869C; -509 C vs T), +869TT genotype in a recessive model (TT vs TC+CC) and 509CC genotype in a dominant model (CC+ CT vs TT) were identified to be related to CI (P<0.05). +869T>C and -509C>T SNPs were in strong linkage disequilibrium (d'=0.87, R2=0.75). Haplotype analysis showed that +869C/-509T haplotype was associated with a significant decreased risk of CI (OR= 0.86, 95%CI, 0.70-0.92; P=0.007). Furthermore,+869T/-509C haplotype was associated with a significant increased risk of CI (OR=1.31, 95%CI, 1.10-2.03; P=0.019).

CONCLUSIONS

The results of this study indicate that polymorphisms and the haplotypes in the TGFβ1 gene might be genetic markers for CI in the Chinese population.

Sepsis-induced acute respiratory distress syndrome with fatal outcome is associated to increased serum transforming growth factor beta-1 levels

BACKGROUND

TGF-β1 is a promoter of pulmonary fibrosis in many chronic inflammatory diseases. TGF-β1 circulating levels in patients with sepsis-induced Acute Respiratory Distress Syndrome (ARDS) have not been established.

METHODS

In this prospective pilot cohort study, serum bioactive TGF-β1 concentration, determined by sandwich ELISA, was analyzed in 52 patients who fulfilled criteria for septic shock at admission and on days 3 and 7.

RESULTS

Of the 52 patients enrolled in the study, 46.1% fulfilled the criteria for ARDS on admission. At ICU admission, there were not statistical differences in TGF-β1 concentrations between septic shock patients with or without ARDS. After 7 days of follow-up in ICU, circulating TGF-β1 levels were significantly higher in patients with sepsis and ARDS than in those without ARDS [55.47 (35.04-79.48 pg/ml) versus 31.65 (22.89-45.63 pg/ml), respectively] (p = 0.002). Furthermore, in septic shock associated ARDS patients, TGF-β1 levels were significantly higher in nonsurvivors than in survivors [85.23 (78.19-96.30 pg/ml) versus 36.41 (30.21-55.47 pg/ml), respectively] (p = 0.006) on day 7 of ICU follow-up.

CONCLUSIONS

In patients with septic shock, persistent ARDS is accompanied with increased circulating TGF-β1 levels. Furthermore, ARDS patients with fatal outcome show higher TGF-β1 concentrations than survivors. These results suggest the relevance of TGF-β1 levels found in the pathogenesis of persistent sepsis-induced ARDS.

Poly(ADP-ribose) polymerase 1 is indispensable for transforming growth factor-β Induced Smad3 activation in vascular smooth muscle cell

Background

Transforming growth factor type-β (TGF-β)/Smad pathway plays an essential role in vascular fibrosis. Reactive oxygen species (ROS) generation also mediates TGF-β signaling-induced vascular fibrosis, suggesting that some sort of interaction exists between Smad and redox pathways. However, the underlying molecular mechanism is largely unknown. This study aims to investigate the influence of poly(ADP-ribose) polymerase 1 (PARP1), a downstream effector of ROS, on TGF-β signaling transduction through Smad3 pathway in rat vascular smooth muscle cells (VSMCs).

Methods and Results

TGF-β1 treatment promoted PARP1 activation through induction of ROS generation in rat VSMCs. TGF-β1-induced phosphorylation and nuclear accumulation of Smad3 was prevented by treatment of cells with PARP inhibitor, 3-aminobenzamide (3AB) or N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-2-(N,N-dimethylamino)acetami (PJ34), or PARP1 siRNA. TGF-β1 treatment promoted poly(ADP-ribosy)lation of Smad3 via activation of PARP1 in the nucleus. Poly(ADP-ribosy)lation enhanced Smad-Smad binding element (SBE) complex formation in nuclear extracts and increased DNA binding activity of Smad3. Pretreatment with 3AB, PJ34, or PARP1 siRNA prevented TGF-β1-induced Smad3 transactivation and expression of Smad3 target genes, including collagen Iα1, collagen IIIα1 and tissue inhibitor of metalloproteinase 1, in rat VSMCs.

Conclusions

PARP1 is indispensable for TGF-β1 induced Smad3 activation in rat VSMCs. Targeting PARP1 may be a promising therapeutic approach against vascular diseases induced by dysregulation of TGF-β/Smad3 pathway.

Exploring anti-TGF-β therapies in cancer and fibrosis

Transforming growth factor-β (TGF-β) is a multifunctional cytokine, with important roles in maintaining tissue homeostasis. TGF-β signals via transmembrane serine/threonine kinase receptors and intracellular Smad transcriptional regulators. Perturbed TGF-β signaling has been implicated in a large variety of pathological conditions. Increased TGF-β levels have been found in patients with cancer, fibrosis, and systemic sclerosis, and were correlated with disease severity. In cancer, TGF-β mediates tumor invasion and metastasis by affecting both tumor cells and the tumor microenvironment including fibroblast activation and immune suppression. Furthermore, TGF-β is a strong stimulator of extracellular matrix deposition. On the basis of these observations, small molecule inhibitors of the TGF-β receptor kinases, neutralizing antibodies that interfere with ligand?receptor interactions, antisense oligonucleotides reducing TGF-β expression, and soluble receptor ectodomains that sequester TGF-β have been developed to intervene with excessive TGF-β signaling activity in the aforementioned disorders. Here, we review the current state of anti-TGF-β therapy in clinical trials.

Association of intronic single-nucleotide polymorphisms in the EMILIN1 gene with essential hypertension in a Chinese population

Studies in mice suggest that the elastin microfibril interfacer-1 gene (EMILIN1), the gene encoding elastin microfibril interfacer-1 protein, contributes to the pathogenesis of essential hypertension (EH) in humans. EMILIN1 in part maintains elastic fibres in vessel walls, and hence peripheral arterial compliance. In a case-control study, we assessed 942 non-obese non-diabetic Chinese, comprising 467 patients with EH and 475 normotensive control subjects (166 without, and 309 with, family history of hypertension in first-degree relatives (FHH)). Hypertension in first-degree relatives occurred in 88%, 65% and 0% of cases, all controls and controls without FHH, respectively. We scanned for single-nucleotide polymorphisms (SNPs) and genotyped them in the EMILIN1 gene using high-resolution melt-curve analysis. No exonic variants were detected. We assessed the association of SNPs and their haplotypes with EH. Three SNPs in introns 1 and 5 (rs2289360, rs2011616 and rs7424556) were in strong pair-wise linkage disequilibrium (r(2)>0.89). All three SNPs were significantly associated with hypertension. Genotypic frequencies at the three SNPs differed significantly between cases and only those controls without FHH. Healthy controls with FHH should be excluded to increase the odds of detecting association. All the G alleles of rs2289360 (odds ratio = 1.69, P = 0.010), rs2011616 (odds ratio = 1.52, P = 0.038) and rs7424556 (odds ratio = 1.59, P = 0.023) were high-risk alleles in the recessive genetic model. We observed significant overall haplotypic association with EH (empirical P = 0.0072); GGG is a risk haplotype (P = 0.043). The overall results support EMILIN1 as a candidate gene for human EH.

Transforming Growth Factor-β1 as a Common Target Molecule for Development of Cardiovascular Diseases, Renal Insufficiency and Metabolic Syndrome

Transforming growth factor-β1 (TGF-β1) is a polypeptide member of the transforming growth factor β superfamily of cytokines. It is a secreted protein that performs many cellular functions including control of cell growth, cell proliferation, cell differentiation and apoptosis. In the cardiovascular system, TGF-β1 plays pivotal roles in the pathogenesis of hypertension, restenosis after percutaneous coronary intervention, atherosclerosis, cardiac hypertrophy and heart failure. In addition, TGF-β1 has been shown to be increased in adipose tissue of obese subjects with insulin resistance. Furthermore, TGF-β1 is a potent initiator of proliferation of renal mesangial cells leading to chronic kidney disease. Some currently available agents can manipulate TGF-β1 expression leading to amelioration of cardiovascular diseases. Thus, an understanding of interactions between chronic kidney disease and metabolic syndrome and the development of cardiovascular diseases is an important issue, and attention should be given to TGF-β1 as a crucial factor for regulation and modulation of those pathological conditions.

Transforming growth factor beta2 is negatively regulated by endogenous retinoic acid during early heart morphogenesis

Vitamin A-deficient (VAD) quail embryos lack the vitamin A-active form, retinoic acid (RA) and are characterized by a phenotype that includes a grossly abnormal cardiovascular system that can be rescued by RA. Here we report that the transforming growth factor, TGFbeta2 is involved in RA-regulated cardiovascular development. In VAD embryos TGFbeta2 mRNA and protein expression are greatly elevated. The expression of TGFbeta receptor II is also elevated in VAD embryos but is normalized by treatment with TGFbeta2-specific antisense oligonucleotides (AS). Administration of this AS or an antibody specific for TGFbeta2 to VAD embryos normalizes posterior heart development and vascularization, while the administration of exogenous active TGFbeta2 protein to normal quail embryos mimics the excessive TGFbeta2 status of VAD embryos and induces VAD cardiovascular phenotype. In VAD embryos pSmad2/3 and pErk1 are not activated, while pErk2 and pcRaf are elevated and pSmad1/5/8 is diminished. We conclude that in the early avian embryo TGFbeta2 has a major role in the retinoic acid-regulated posterior heart morphogenesis for which it does not use Smad2/3 pathways, but may use other signaling pathways. Importantly, we conclude that retinoic acid is a critical negative physiological regulator of the magnitude of TGFbeta2 signals during vertebrate heart formation.

Does over-expression of transforming growth factor-beta account for the increased morbidity in African-Americans?: possible clinical study and therapeutic implications

African-Americans experience an excessive prevalence of a number of apparently disparate disorders that all appear to be, at least in part, mediated by the over-expression or activation of transforming growth factor-beta (TGF-beta) signaling pathways, and that certain genotypes including the codon 10 polymorphism occur more commonly among African-Americans and appears to predispose to these disorders. These disorders, fibrosing in nature, include hypertension, focal glomerulosclerosis, diabetic nephropathy, end stage renal disease, sarcoidosis, uterine leiomyoma, keloids, myocardial fibrosis, and glaucoma. The specific polymorphism for TGF-beta, codon 10, has been implicated in glomerulosclerosis and diabetic nephropathy as well as cardiac transplant rejection. Although TGF-beta over-expression is not the sole factor in these disorders, it is suggested that by designing future clinical studies that consider genomic differences in TGF-beta expression, a more complete understanding of these clinical disorders will be possible. A more thorough understanding of the genetic basis of disease will like promote improved therapeutic regimens and may help reduce the disparate health outcomes for African-Americans as well as improve treatment of individuals of various and diverse ethnic backgrounds.

Role of transforming growth factor Beta in corneal function, biology and pathology

Transforming growth factor-beta (TGFbeta) is a pleiotropic multifunctional cytokine that regulates several essential cellular processes in many parts of the body including the cornea. Three isoforms of TGFbeta are known in mammals and the human cornea expresses all of them. TGFbeta1 has been shown to play a central role in scar formation in adult corneas whereas TGFbeta2 and TGFbeta3 have been implicated to play a critical role in corneal development and scarless wound healing during embryogenesis. The biological effects of TGFbeta in the cornea have been shown to follow Smad dependent as well as Smad-independent signaling pathways depending upon cellular responses and microenvironment. Corneal TGFbeta expression is necessary for maintaining corneal integrity and corneal wound healing. On the other hand, TGFbeta is perhaps the most important cytokine in the pathogenesis of fibrotic disease in the cornea. Although the transformation of keratocytes to myofibroblasts induced by TGFbeta is largely believed to cause corneal fibrosis or scarring, the precise molecular mechanism(s) involved in this process is still unknown. Currently no drugs are available to treat corneal scarring effectively without causing significant side effects. Many approaches to treat TGFbeta-mediated corneal scarring are under investigation. These include blocking of TGFbeta, TGFbeta receptor, TGFbeta function and/or TGFbeta maturation. Other strategies such as modulating keratocyte proliferation, apoptosis, transcription and DNA condensation are also being investigated. The potential of gene therapy to neutralize the pathologic effects of TGFbeta has also been demonstrated recently.

Vitamin A-not for your eyes only: requirement for heart formation begins early in embryogenesis

Vitamin A insufficiency has profound adverse effects on embryonic development. Major advances in understanding the role of vitamin A in vertebrate heart formation have been made since the discovery that the vitamin A active form, all-trans-retinoic acid, regulates many genes, including developmental genes. Among the experimental models used, the vitamin A-deficient avian embryo has been an important tool to study the function of vitamin A during early heart formation. A cluster of retinoic acid-regulated developmental genes have been identified that participate in building the heart. In the absence of retinoic acid the embryonic heart develops abnormally leading to embryolethality.

Emilin1 gene and essential hypertension: a two-stage association study in northern Han Chinese population

Background

Elastogenesis of elastic extracellular matrix (ECM) which was recognized as a major component of blood vessels has been believed for a long time to play only a passive role in the dynamic vascular changes of typical hypertension. Emilin1 gene participated in the transcription of ECM's formation and was recognized to modulate links TGF-β maturation to blood pressure homeostasis in animal study. Recently relevant advances urge further researches to investigate the role of Emilin1 gene in regulating TGF-β signals involved in elastogenesis and vascular cell defects of essential hypertension (EH).

Methods

We designed a two-stage case-control study and selected three single nucleotide polymorphisms (SNPs), rs3754734, rs2011616 and rs2304682 from the HapMap database, which covered Emilin1 gene. Totally 2,586 subjects were recruited from the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA). In stage 1, all the three SNPs of the Emilin1 gene were genotyped and tested within a subsample including 503 cases and 490 controls, significant SNPs would enter into stage 2 including 814 cases with hypertension and 779 controls and analyze on the basis of testing total 2,586 subjects.

Results

In stage 1, single locus analyses showed that SNPs rs3754734 and rs2011616 had significant association with EH (P < 0.05). In stage 2, weak association for dominant model were observed by age stratification and odds ratio (ORs) of TG+GG vs. TT of rs3754734 were 0.768 (0.584-1.009), 0.985 (0.735-1.320) and 1.346 (1.003-1.806) in < 50, 50-59 and ≥ 60 years group and ORs of GA+AA vs. GG of rs2011616 were 0.745 (0.568-0.977), 1.013 (0.758-1.353) and 1.437 (1.072-1.926) in < 50, 50-59 and ≥ 60 years group respectively. Accordingly, significant interactions were detected between genotypes of rs3754734 and rs2011616 and age for EH, and ORs were 1.758 (1.180-2.620), P = 0.006 and 1.903 (1.281-2.825), P = 0.001, respectively. Results of haplotypes analysis showed that there weren't any haplotypes associated with EH directly, but the interaction of hap2 (GA) and age-group found to be significant after being adjusted for the covariates, OR was 1.220 (1.031-1.444), P value was 0.020.

Conclusion

Our findings don't support positive association of Emilin1 gene with EH, but the interaction of age and genotype variation of rs3754734 and rs2011616 might increase the risk to hypertension.

The American Journal of Cardiology and Journal of Periodontology editors' consensus: periodontitis and atherosclerotic cardiovascular disease

ACKNOWLEDGMENT

This Editors' Consensus is supported by an educational grant from Colgate-Palmolive, Inc., New York, New York, and is based on a meeting of the authors held in Boston, Massachusetts, on January 9, 2009.

DISCLOSURE

Dr. Friedewald has received honoraria for speaking from Novartis, East Hanover, New Jersey. Dr. Kornman is a full-time employee and shareholder of Interleukin Genetics, Waltham, Massachusetts, which owns patents on genetic biomarkers for chronic inflammatory diseases. Dr. Genco is a consultant to Merck, Whitehouse Station, New Jersey. Dr. Ridker has received research support from AstraZeneca, Wilmington, Delaware; Novartis; Pfizer, New York, New York; Roche, Nutley, New Jersey; Sanofi-Aventis, Bridgewater, New Jersey; and Abbott Laboratories, Abbott Park, Illinois. Dr. Ridker has received non-financial research support from Amgen, Thousand Oaks, California. Dr. Ridker is a co-inventor on patents held by Brigham and Women's Hospital that relate to the use of inflammatory biomarkers in cardiovascular disease. Dr. Ridker is a research consultant for Schering-Plough, Kenilworth, New Jersey; Sanofi-Aventis; AstraZeneca; Isis, Carlsbad, California; Novartis; and Vascular Biogenics, Tel Aviv, Israel. Dr. Van Dyke is a co-inventor on patents held by Boston University, Boston, Massachusetts, that relate to inflammation control, including consulting fees. Dr. Roberts has received honoraria for speaking from Merck, Schering-Plough, AstraZeneca, and Novartis. All other individuals in a position to control content disclosed no relevant financial relationships.

C-Peptide: the missing link in diabetic nephropathy?

Proinsulin C-peptide has been found to exert beneficial effects in many tissues affected by diabetic microvascular complications, including the kidneys. Glomerular hyperfiltration and microalbuminuria are early markers of diabetic nephropathy. C-peptide at physiological concentrations effectively reduces diabetes-induced glomerular hyperfiltration via constriction of the afferent arteriole, dilation of the efferent arteriole, and inhibition of tubular reabsorption in experimental models of type 1 diabetes. The glomerular hypertrophy and mesangial matrix expansion seen in early diabetes can be reduced or prevented by C-peptide administration, possibly via interference with TGF-beta1 and TNFalpha signaling. Several of C-peptide's reno-protective effects have been confirmed in human studies; reduced glomerular hyperfiltration and diminished urinary albumin excretion have been documented in type 1 diabetes patients receiving replacement doses of C-peptide for periods of up to 3 months. In this review, we critically summarize the current state of knowledge regarding C-peptide's renal effects, and discuss possible mechanisms of its beneficial effects in diabetic nephropathy.

Effects of alpha-lipoic acid on transforming growth factor beta1-p38 mitogen-activated protein kinase-fibronectin pathway in diabetic nephropathy

In diabetic nephropathy, transforming growth factor beta1 (TGFbeta1) is related to p38 mitogen-activated protein kinase (MAPK) that induces production of fibronectin in mesangial cells. We investigated the effects of alpha-lipoic acid (ALA), a potent antioxidant, on proteinuria and TGFbeta1-p38 MAPK-fibronectin pathway in diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. After ALA treatment for 5 weeks in OLETF rats at 30 weeks of age, plasma malondialdehyde, urinary protein excretion, renal cortical TGFbeta1, and fibronectin protein levels were decreased; and urinary protein excretion was positively correlated with renal cortical TGFbeta1 and fibronectin protein levels. Phospho-form but not total-form levels as well as fold activations of each protein consisting of p38 MAPK pathway were also attenuated. These results suggest that ALA ameliorates proteinuria by attenuating expressions of TGFbeta1 and fibronectin proteins, and these favorable effects are related to inhibition of phosphorylating activation of p38 MAPK pathway in renal cortex of OLETF rats.

Circulating transforming growth factor-beta1 levels and the risk for kidney disease in African Americans

Transforming growth factor-β1 (TGF-β1) is well known to induce progression of experimental renal disease. Here we determined whether there is an association between serum levels of TGF-β1 and the risk factors for progression of clinically relevant renal disorders in 186 black and 147 white adults none of whom had kidney disease or diabetes. Serum TGF-β1 protein levels were positively and significantly associated with plasma renin activity along with the systolic and diastolic blood pressure in blacks but not whites after controlling for age, gender and body mass index. These TGF-β1 protein levels were also significantly associated with body mass index and metabolic syndrome and more predictive of microalbuminuria in blacks than in whites. The differential association between TGF-β1 and renal disease risk factors in blacks and whites suggests an explanation for the excess burden of end-stage renal disease in the black population but this requires validation in an independent cohort. Whether these findings show that it is the circulating levels of TGF-β1 that contributes to renal disease progression or reflects other unmeasured factors will need to be tested in longitudinal studies.

Transforming growth factor-beta1 869T/C, but not interleukin-6 -174G/C, polymorphism associates with hypertension in rheumatoid arthritis

OBJECTIVES

Part of the deleterious effects of systemic inflammation on the cardiovascular system of patients with RA may be exerted via increased propensity to hypertension. IL-6 and TGF-beta1 are important regulators of the inflammatory response. In some, but not all, studies, IL6 -174G/C (rs1800795) and TGFB1 869T/C (rs1982073) gene polymorphisms have been associated with hypertension in the general population. The present study addressed their potential association with hypertension in RA patients.

METHODS

TGFB1 869T/C and IL6 -174G/C were identified in 400 RA patients and 422 local, non-RA controls using real-time PCR and melting curve analysis. Binary logistic and linear regression models were used to identify the independence of the effects of the polymorphisms on hypertension.

RESULTS

Genotypic and allelic frequencies of the two polymorphisms were similar in RA and controls. Within the RA group, there was no significant association between IL6 -174G/C and hypertension, but TGF 869T-allele carriers had significantly increased prevalence of hypertension compared with CC homozygotes (70.2 vs 55.2%; P = 0.023). This association remained significant after adjustment for other hypertension risk factors and medication (odds ratio = 1.96; 95% CI 1.02, 3.77; P = 0.044), and was more pronounced in patients with increased systemic inflammation.

CONCLUSIONS

This study suggests an association of TGFB1 869T/C, but not of IL6 -174G/C, with hypertension in RA patients. If this finding is confirmed in prospective studies, this polymorphism could be used as a screening tool for RA patients with higher risk of developing hypertension and lead to increased surveillance and earlier treatment.

Hypertension and microvascular remodelling

In the present review, microvascular remodelling refers to alterations in the structure of resistance vessels contributing to elevated systemic vascular resistance in hypertension. We start with some historical aspects, underscoring the importance of Folkow's contribution made half a century ago. We then move to some basic concepts on the biomechanics of blood vessels, and explicit the definitions proposed by Mulvany for specific forms of remodelling, especially inward eutrophic and inward hypertrophic. The available evidence for the existence of remodelled resistance vessels in hypertension comes next, with relatively more weight given to human, in comparison with animal data. Mechanisms are discussed. The impact of antihypertensive drug treatment on remodelling is described, again with emphasis on human data. Some details are given on the three studies to date which point to remodelling of subcutaneous resistance arteries as an independent predictor of cardiovascular risk in hypertensive patients. We terminate by considering the potential role of remodelling in the pathogenesis of end-organ damage and in the perpetuation of hypertension.

Genetic polymorphisms of the RAS-cytokine pathway and chronic kidney disease

Chronic kidney disease (CKD) in children is irreversible. It is associated with renal failure progression and atherosclerotic cardiovascular (CV) abnormalities. Nearly 60% of children with CKD are affected since birth with congenital or inherited kidney disorders. Preliminary evidence primarily from adult CKD studies indicates common genetic risk factors for CKD and atherosclerotic CV disease. Although multiple physiologic pathways share common genes for CKD and CV disease, substantial evidence supports our attention to the renin angiotensin system (RAS) and the interlinked inflammatory cascade because they modulate the progressions of renal and CV disease. Gene polymorphisms in the RAS-cytokine pathway, through altered gene expression of inflammatory cytokines, are potential factors that modulate the rate of CKD progression and CV abnormalities in patients with CKD. For studying such hypotheses, the cooperative efforts among scientific groups and the availability of robust and affordable technologies to genotype thousands of single nucleotide polymorphisms (SNPs) across the genome make genome-wide association studies an attractive paradigm for studying polygenic diseases such as CKD. Although attractive, such studies should be interpreted carefully, with a fundamental understanding of their potential weaknesses. Nevertheless, whole-genome association studies for diabetic nephropathy and future studies pertaining to other types of CKD will offer further insight for the development of targeted interventions to treat CKD and associated atherosclerotic CV abnormalities in the pediatric CKD population.

Extracellular control of TGFbeta signalling in vascular development and disease

The intracellular mechanism of transforming growth factor-beta (TGFbeta) signalling via kinase receptors and SMAD effectors is firmly established, but recent studies of human cardiovascular syndromes such as Marfan syndrome and pre-eclampsia have refocused attention on the importance of regulating the availability of active extracellular TGFbeta. It seems that elastic extracellular matrix (ECM) components have a crucial role in controlling TGFbeta signalling, while soluble and membrane bound forms of TGFbeta co-receptors add further layers of regulation. Together, these extracellular interactions determine the final bioavailability of TGFbeta to vascular cells, and dysregulation is associated with an increasing number of vascular pathologies.

Transforming Growth Factor-β1 Impairs Endothelin-1-Mediated Contraction of Brain Vessels by Inducing Mitogen-Activated Protein (MAP) Kinase Phosphatase-1 and Inhibiting p38 MAP Kinase

Brain levels of transforming growth factor-beta1 (TGF-beta1) are increased in Alzheimer's disease and have been implicated in the associated cerebrovascular pathology. We recently reported that transgenic mice that overexpress TGF-beta1 (TGF+ mice) display, with aging, selectively reduced endothelin-1 (ET-1)-mediated contractions. Because ET-1 is a key regulator of cerebrovascular tone and homeostasis, we investigated how increased levels of TGF-beta1 could selectively alter this contractile response. We found that ETA receptors, via activation of p38 mitogen-activated protein (MAP) kinase, mediate the ET-1-induced contraction in mouse cerebral arteries, a response significantly decreased in aged TGF+ mice (-39%; p < 0.01) despite unaltered ETA receptor levels or affinity. In cerebrovascular smooth muscle cell cultures, long-term treatment with TGF-beta1 significantly decreased (>50%; p < 0.05) the ET-1-induced activation of the p38 MAPK/27-kDa heat shock protein (HSP27) signaling pathway. This occurred with no effect upstream to p38 MAP kinase but with the concomitant induction of mitogen-activated protein kinase phosphatase-1 (MKP-1) expression. Inhibition of MKP-1 expression with Ro-31-8220 or suppression of MKP-1 expression by short interfering RNA restored the ET-1-mediated p38 MAP kinase response. These results disclose a new role for long-term increases of TGF-beta1 in modulating cerebrovascular tone by dampening ET-1-mediated activation of the p38 MAPK/HSP27 signaling pathway. Such changes in ET-1-mediated signaling may help maintain vascular wall homeostasis by compensating for the diminished dilatory function induced by TGF-beta1 and amyloid-beta; brain levels of these two molecules are increased in patients with Alzheimer's disease.

The role of angiotensin AT1 receptor-associated protein in renin-angiotensin system regulation and function

We cloned a novel molecule, AT1 receptor-associated protein (ATRAP), which is expressed in many tissues but specifically interacts with the AT1 receptor carboxyl-terminal. In the kidney, ATRAP was broadly distributed along the renal tubules; salt intake modulated its expression. In cardiovascular cells, angiotensin II (Ang II) stimulation made ATRAP co-localized with AT1 receptor in cytoplasm; ATRAP overexpression decreased cell surface AT1 receptor. In downstream signaling pathways, ATRAP suppressed Ang II-induced phosphorylation of mitogen-activated protein kinase, activation of c-fos gene transcription, and enhancement of amino acid or bromodeoxyuridine incorporation in cardiovascular cells. Thus, cardiovascular ATRAP may promote AT1 receptor internalization and attenuate Ang II-mediated cardiovascular remodeling. We would expect ATRAP to become a new therapeutic target molecule to treat and prevent cardiovascular remodeling in hypertension.

Pericytes may have an important role in the pathogenesis of vascular malformations

Vascular malformations are a series of congenital developmental abnormalities. The defects in vascular remodeling may contribute to the formation of these unique entities. Pericytes are the component of microvascular system and play a key role in vascular remodeling. It is logical to propose pericytes may play an important role in the pathogenesis of vascular malformations. Target therapies against pericytes probably bring new sight into vascular malformations treatment.