Cavin-1 regulates BMP/Smad signaling through the interaction of Caveolin-1 with BMPRII in pulmonary artery endothelial cells

Background

Pulmonary hypertension (PH) is a progressive disease associated with poor outcome. Caveolin-1 (Cav1) is a component of caveolae and classified as a related gene of pulmonary arterial hypertension (PAH). Gene mutations of bone morphogenetic protein type II receptor (BMPRII) is a most common cause of PAH. BMPRII is localized in caveolae and associates with Cav1. However, the role of the Caveolin-Cavin system on the BMP/Smad signaling and the PAH progression has not been well-known.

Purpose

The aim of our study is to investigate the relationship between Caveolin-Cavin system and BMP/Smad signaling pathway and explore the mechanism of downstream signal transduction of BMP signaling by the interaction between Caveolin and BMPRII.

Methods

Cav1 knockout mice were used to assess PH and caveolae in pulmonary artery endothelial cells were observed by electron microscope. Cav1 and Cavin-1, which is a component of caveolae and form a complex with Cav1, were knocked-down in human pulmonary artery endothelial cell (hPAEC) using siRNA and phosphorylation of Smad signal was evaluated. Apoptosis of these cells was explored by flow cytometry. We investigated the interaction between Cav1 and BMPRII, and evaluated whether Cavin-1 affects this interaction and signal transduction of BMP signaling.

Results

As previously described, deletion of Cav1 revealed disappearance of caveolae in pulmonary artery endothelial cells (PAECs), and Cav1 knockout mice exhibited PH with pulmonary vascular remodeling and right ventricular hypertrophy. We then examined roles of Cav1 in human PAECs (hPAECs). Cav1 knockdown in hPAECs reduced phosphorylation of Smad 1/5/9. In addition, Cav1 knockdown significantly increased hypoxia-induced apoptosis in hPAEC. Knockdown of Cavin-1 reversed phosphorylation of Smad 1/5/9 decreased by Cav1 knockdown in BMP9 stimulation. Cavin-1 reversed the expression of BMPRII decreased by overexpression of Cav1. Cav1 was associated with Cavin-1 at the plasma membrane in PAECs. Cav1 also associated with BMPRII at the membrane of hPAECs that was inhibited by Cavin-1, and Cavin-1 reduced the localization of BMPRII to the membrane of hPAECs. These results suggest that BMPRII interacts with Cav1 via Cavin-1-associated localization at the plasma membrane in hPAECs, resulting in regulating BMP/Smad signaling pathway and involving in the development of PAH.

Conclusions

Cavin-1 affects the interaction of Cav1 with BMPRII at the membrane of PAECs, and regulates BMP/Smad signaling. These results reveal a previously undescribed function of Cavin-Caveolin system in the development of PAH through regulation of BMP/Smad signaling.

Funding Acknowledgement

Type of funding source: None

SDPR/Cavin-2 loss inhibits monocyte adhesion to endothelial cells in abdominal aortic aneurysm via suppressing the expression of adhesion molecules

Background

Abdominal aortic aneurysm (AAA) is a common and life-threatening vascular disease. The initial phase of AAA progression is vascular inflammation. Inflammation sites present adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1). These molecules play a crucial role in recruiting inflammatory cells to endothelial cells through NF-κB signaling. Endothelial cells express serum deprivation response (SDPR)/Cavin-2 localized in caveolae on the cell membrane. Although Cavin-2 is involved in such as cell proliferation, migration, and signal transduction, the role of Cavin-2 in vascular inflammation in the development of AAA is still unclear.

Purpose

To assess the influence of Cavin-2 deficiency in AAA development and clarify the role of Cavin-2 in the regulation of inflammatory cell adhesion in endothelial cells.

Methods

CaCl2-induced AAAs were induced by the periaortic application of 0.5 M CaCl2 in male SDPR-knockout (KO) and wild-type (WT) mice at 8–10 weeks of age. Angiotensin II (Ang II)-induced AAAs were created by 4-week-subcutaneous drug infusion in male ApoE-KO and ApoE/Cavin-2-double KO (DKO) mice at 24 weeks of age. Inflammatory response and cell adhesion were evaluated using human aortic endothelial cells (HAECs) and human monocytes (THP-1 cells).

Results

Six weeks after CaCl2 treatment, Cavin-2 deficiency significantly attenuated the development of AAAs. Elastin degradation was markedly suppressed and F4/80-positive macrophages infiltration in aortic walls were decreased in Cavin-2-KO mice. Although Ang II infusion for 4 weeks formed AAAs in ApoE KO mice and ApoE/Cavin-2-DKO mice, ApoE/Cavin-2-DKO mice exhibited the suppression of AAA formation independently of blood pressure. Immunohistochemical staining showed VCAM-1 expression on endothelial cells was suppressed in ApoE/Cavin-2-DKO mice. Further, in vitro co-culture experiment, the number of THP-1 cells adhered to TNF-treated SDPR-knockdown HAECs was decreased compared with that to control HAECs. Moreover, mRNA expression of VCAM-1 and ICAM-1 was decreased in TNFα-treated SDPR-knockdown HAECSs. Protein expression of VCAM-1 was also suppressed in TNFα-treated SDPR-knockdown HAECSs. The activity of NF-κB p65, an upstream regulator of VCAM-1 and ICAM-1,tended to be suppressed in TNFα-treated SDPR-knockdown HAECs.

Conclusion

In this study, we revealed that SDPR/Cavin-2 loss attenuated AAA development with the suppression of elastin degradation and macrophage infiltration. Our findings suggest that SDPR/Cavin-2 in the endothelial cells regulates the expression of adhesion molecules via NF-κB signaling and promotes the adhesion and infiltration of inflammatory cells to the aortic wall.

Funding Acknowledgement

Type of funding source: None

Aneuploid rescue precedes X-chromosome inactivation and increases the incidence of its skewness by reducing the size of the embryonic progenitor cell pool

STUDY QUESTION

Do monosomy rescue (MR) and trisomy rescue (TR) in preimplantation human embryos affect other developmental processes, such as X-chromosome inactivation (XCI)?

SUMMARY ANSWER

Aneuploid rescue precedes XCI and increases the incidence of XCI skewness by reducing the size of the embryonic progenitor cell pools.

WHAT IS KNOWN ALREADY

More than half of preimplantation human embryos harbor aneuploid cells, some of which can be spontaneously corrected through MR or TR. XCI in females is an indispensable process, which is predicted to start at the early-blastocyst phase.

STUDY DESIGN, SIZE, DURATION

We examined the frequency of XCI skewness in young females who carried full uniparental disomy (UPD) resulting from MR or TR/gamete complementation (GC). The results were statistically analyzed using a theoretical model in which XCI involves various numbers of embryonic progenitor cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We studied 39 children and young adults ascertained by imprinting disorders. XCI ratios were determined by DNA methylation analysis of a polymorphic locus in the androgen receptor gene. We used Bayesian approach to assess the probability of the occurrence of extreme XCI skewness in the MR and TR/GC groups using a theoretical model of 1-12 cell pools.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 12 of 39 individuals (31%) showed skewed XCI. Extreme skewness was observed in 3 of 15 MR cases (20%) and 1 of 24 TR/GC cases (4.2%). Statistical analysis indicated that XCI in the MR group was likely to have occurred when the blastocyst contained three or four euploid embryonic progenitor cells. The estimated size of the embryonic progenitor cell pools was approximately one-third or one-fourth of the predicted size of normal embryos. The TR/GC group likely had a larger pool size at the onset of XCI, although the results remained inconclusive.

LIMITATIONS, REASONS FOR CAUTION

This is an observational study and needs to be validated by experimental analyses.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides evidence that the onset of XCI is determined by an intrinsic clock, irrespectively of the number of embryonic progenitor cells. Our findings can also be applied to individuals without UPD or imprinting disorders. This study provides a clue to understand chromosomal and cellular dynamics in the first few days of human development, their effects on XCI skewing and the possible implications for the expression of X-linked diseases in females.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Grants-in-aid for Scientific Research on Innovative Areas (17H06428) and for Scientific Research (B) (17H03616) from Japan Society for the Promotion of Science (JSPS), and grants from Japan Agency for Medical Research and Development (AMED) (18ek0109266h0002 and 18ek0109278h0002), National Center for Child Health and Development and Takeda Science Foundation. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

Homogeneous Intrinsic Neuronal Excitability Induces Overfitting to Sensory Noise: A Robot Model of Neurodevelopmental Disorder

Neurodevelopmental disorders, including autism spectrum disorder, have been intensively investigated at the neural, cognitive, and behavioral levels, but the accumulated knowledge remains fragmented. In particular, developmental learning aspects of symptoms and interactions with the physical environment remain largely unexplored in computational modeling studies, although a leading computational theory has posited associations between psychiatric symptoms and an unusual estimation of information uncertainty (precision), which is an essential aspect of the real world and is estimated through learning processes. Here, we propose a mechanistic explanation that unifies the disparate observations via a hierarchical predictive coding and developmental learning framework, which is demonstrated in experiments using a neural network-controlled robot. The results show that, through the developmental learning process, homogeneous intrinsic neuronal excitability at the neural level induced via self-organization changes at the information processing level, such as hyper sensory precision and overfitting to sensory noise. These changes led to multifaceted alterations at the behavioral level, such as inflexibility, reduced generalization, and motor clumsiness. In addition, these behavioral alterations were accompanied by fluctuating neural activity and excessive development of synaptic connections. These findings might bridge various levels of understandings in autism spectrum and other neurodevelopmental disorders and provide insights into the disease processes underlying observed behaviors and brain activities in individual patients. This study shows the potential of neurorobotics frameworks for modeling how psychiatric disorders arise from dynamic interactions among the brain, body, and uncertain environments.

Mechanical regulation of bone homeostasis through p130Cas-mediated alleviation of NF-κB activity

Mechanical loading plays an important role in bone homeostasis. However, molecular mechanisms behind the mechanical regulation of bone homeostasis are poorly understood. We previously reported p130Cas (Cas) as a key molecule in cellular mechanosensing at focal adhesions. Here, we demonstrate that Cas is distributed in the nucleus and supports mechanical loading-mediated bone homeostasis by alleviating NF-κB activity, which would otherwise prompt inflammatory processes. Mechanical unloading modulates Cas distribution and NF-κB activity in osteocytes, the mechanosensory cells in bones. Cas deficiency in osteocytes increases osteoclastic bone resorption associated with NF-κB-mediated RANKL expression, leading to osteopenia. Upon shear stress application on cultured osteocytes, Cas translocates into the nucleus and down-regulates NF-κB activity. Collectively, fluid shear stress-dependent Cas-mediated alleviation of NF-κB activity supports bone homeostasis. Given the ubiquitous expression of Cas and NF-κB together with systemic distribution of interstitial fluid, the Cas-NF-κB interplay may also underpin regulatory mechanisms in other tissues and organs.

Abstract P1-12-03: Prevalence, predictive factors, and clinical outcomes of anthracycline induced cardiac dysfunction among patients with breast cancer in Japan, where the normal body weight (BMI < 25) is dominant

Objective: Cardiac dysfunction (CD) is a major clinical problem for survivors of breast cancer. ASCO released a guideline for prevention and monitoring CD in survivors of adult cancer in 2017. Exposure to anthracycline (A) and trastuzumab are both risk factor for CD, as well as obesity is a part of multiple risk factors in the guideline. Meta-analysis shown obesity itself increases risk of A induced CD (A-CD). Prevalence of obesity and CD among non-oncology patients vary in countries, as many Western countries have obesity dominant population. Then little is known about clinical characteristics of A-CD in survivors of adult cancer among normal weight dominant countries, especially in Asia. This study was conducted to understand characteristics of A-CD among patients with breast cancer in Japan.

Method: This study used electrical charts, breast oncology database, and cardiology database to find prevalence, predictive factors, and clinical outcomes of A-CD in Hyogo Cancer Center. The definition of CD is based on diagnosis by the cardiologist. Major Cardiac Events (MACE) is defined as cardiac death or emergency admission due to CD. Obesity is defined as BMI > 30, normal body weight is defined as BMI < 25, and elderly is defined as age > 60 years old, same as in ASCO guideline. Patients gave written informed consent. IRB approved this study.

Result: From Apr. 2006, to Mar. 2017, 855 patients received A for the treatment of breast cancer. Median body weight was 55 Kg, median BMI was 23, and 93.4 % of patients are non-obese. Half of patients (46.9 %) are elderly. Almost a quarter (24 %) of patients received trastuzumab. At the median follow up 60 months, 20 patients (2.3 %) experienced CD, one patient (0.11 %) passed away due to CD, and four patients were admitted as emergency, then five patients (0.58 %) experienced MACE. Median time to onset of CD after the last dose of A is seven months. Among patients with CD, 18 patients (90 %) recovered their ejection fraction (EF), and the median time to recover of EF was two months. Predictive factors for CD include usage of trastuzumab (15 patients), elderly (eight patients), high dose anthracycline (four patients), and multiple cardiac risk factors at base line (four patients). Among patients treated without trastuzumab, only five (0.76 %) patients experienced CD, but four of them experienced MACE.

Conclusion: Prevalence of A-CD in the normal weight dominant population was lower than reported in obesity dominant population, especially in patients treated without trastuzumab. In this population, clinical outcome such as prevalence of MACE may vary depending on the usage of trastuzumab. Further study is warranted to set an optimal strategy for the prevention and monitoring of A-CD in non-obese dominant population.

Citation Format: Matsumoto K, Nonaka A, Ogata T, Ogata M, Sakai H, Nishimura M, Onoe T, Soyama M, Hashimoto K, Tane K, Hirokaga K, Takao S. Prevalence, predictive factors, and clinical outcomes of anthracycline induced cardiac dysfunction among patients with breast cancer in Japan, where the normal body weight (BMI < 25) is dominant [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-03.

A Neurorobotics Simulation of Autistic Behavior Induced by Unusual Sensory Precision

Recently, applying computational models developed in cognitive science to psychiatric disorders has been recognized as an essential approach for understanding cognitive mechanisms underlying psychiatric symptoms. Autism spectrum disorder is a neurodevelopmental disorder that is hypothesized to affect information processes in the brain involving the estimation of sensory precision (uncertainty), but the mechanism by which observed symptoms are generated from such abnormalities has not been thoroughly investigated. Using a humanoid robot controlled by a neural network using a precision-weighted prediction error minimization mechanism, it is suggested that both increased and decreased sensory precision could induce the behavioral rigidity characterized by resistance to change that is characteristic of autistic behavior. Specifically, decreased sensory precision caused any error signals to be disregarded, leading to invariability of the robot's intention, while increased sensory precision caused an excessive response to error signals, leading to fluctuations and subsequent fixation of intention. The results may provide a system-level explanation of mechanisms underlying different types of behavioral rigidity in autism spectrum and other psychiatric disorders. In addition, our findings suggest that symptoms caused by decreased and increased sensory precision could be distinguishable by examining the internal experience of patients and neural activity coding prediction error signals in the biological brain.