Biology subjects

D'Amore, A.

Publications and source records attributed to D'Amore, A..

5 recordsLinked to original sources

bioRxiv2024

AKT-mediated phosphorylation of TSC2 controls stimulus and tissue-specific mTORC1 signaling and organ growth

Mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) integrates diverse intracellular and extracellular growth signals to regulate cell and tissue growth. How the molecular mechanisms regulating mTORC1 signaling established through biochemical and cell biological studies function under physiological states in specific mammalian tissues are unknown. Here, we characterize a genetic mouse model lacking the 5 phosphorylation sites on the tuberous sclerosis complex 2 (TSC2) protein through which the growth factor-stimulated protein kinase AKT can active mTORC1 signaling in cell culture models. These phospho-mutant mice (TSC2-5A) are developmentally normal but exhibit reduced body weight and the weight of specific organs, such as brain and skeletal muscle, associated with cell intrinsic decreases in growth factor-stimulated mTORC1 signaling. The TSC2-5A mouse model demonstrates that TSC2 phosphorylation is a primary mechanism of mTORC1 activation in some, but not all, tissues and provides a genetic tool to facilitate studies on the physiological regulation of mTORC1.

cell biology↗

bioRxiv2024

Intervening to preserve function in ischemic cardiomyopathy with a porous hydrogel and extracellular matrix composite in a rat myocardial infarction model

A variety of hydrogels have been developed for intramyocardial injection therapy after myocardial infarction. Some of these biomaterials have incorporated bioactive substances that promote local tissue regeneration and integration, while others have emphasized the mechanical role of the injectate in providing functional benefit. In this study, we incorporated two bioactive features, porosity, and extracellular matrix derived hydrogel (ECM), into a mechanically optimized, thermoresponsive, degradable hydrogel (poly(N-isopropylacrylamide-co-N-vinylpyrrolidone-co-MAPLA) copolymer) and evaluated whether injection of this biomaterial could abrogate the remodeling process in a rat ischemic cardiomyopathy model. After myocardial infarction by coronary artery ligation, rats were randomly divided into four groups: group NP (non-porous hydrogel) without either ECM or porosity, group PM (porous hydrogel) from the same synthetic copolymer with mannitol beads as porogens, and group PME with porosity and ECM digest added to the synthetic copolymer. A group with PBS injection alone served as a control. Intramyocardial injections were made 3 days after myocardial infarction. Serial echocardiography was assessed over time, and histological assessments were performed eight weeks after infarction. Results demonstrated improved echocardiographic function and neovascularization in the PME group compared to the other hydrogels and PBS injection. The PME group also demonstrated significant improvement in LV geometry and macrophage polarization (towards M2) compared to the PBS group, whereas these differences were not observed in the NP or PM groups versus the control. These results demonstrate that further functional improvement may be achieved in hydrogel injection therapy for ischemic cardiomyopathy by incorporating porosity and ECM digest, representing a combination of mechanical and biological effects.

bioengineering↗

bioRxiv2023

Dynamical modeling reveals RNA decay mediates the effect of matrix stiffness on aged muscle stem cell fate

Loss of muscle stem cell (MuSC) self-renewal with aging reflects a combination of influences from the intracellular (e.g., post-transcriptional modifications) and extracellular (e.g., matrix stiffness) environment. Whereas conventional single cell analyses have revealed valuable insights into factors contributing to impaired self-renewal with age, most are limited by static measurements that fail to capture nonlinear dynamics. Using bioengineered matrices mimicking the stiffness of young and old muscle, we showed that while young MuSCs were unaffected by aged matrices, old MuSCs were phenotypically rejuvenated by young matrices. Dynamical modeling of RNA velocity vector fields in silico revealed that soft matrices promoted a self-renewing state in old MuSCs by attenuating RNA decay. Vector field perturbations demonstrated that the effects of matrix stiffness on MuSC self-renewal could be circumvented by fine-tuning the expression of the RNA decay machinery. These results demonstrate that post-transcriptional dynamics dictate the negative effect of aged matrices on MuSC self-renewal. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC="FIGDIR/small/529950v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1a840corg.highwire.dtl.DTLVardef@d354cforg.highwire.dtl.DTLVardef@650556org.highwire.dtl.DTLVardef@41587c_HPS_FORMAT_FIGEXP M_FIG Graphical abstract description: The balance of self-renewal and differentiation in young muscle stem cells (MuSCs) is robust to perturbations of the biophysical microenvironment. In contrast, aged MuSCs are highly sensitive to extrinsic perturbations, and exposure to a youthful microenvironment rejuvenates the self-renewing potential of aged MuSCs by modulating post-transcriptional RNA dynamics. C_FIG

cell biology↗

bioRxiv2022

Mammary Tissue-Derived Extracellular Matrix Hydrogels Reveal the Role of the Irradiated Microenvironment in Breast Cancer Recurrence

Radiation therapy (RT) is essential for triple negative breast cancer (TNBC) treatment. However, patients with TNBC continue to experience recurrence after RT. The role of the extracellular matrix (ECM) of irradiated breast tissue in tumor recurrence is still unknown. In this study, we evaluated the structure, molecular composition, and mechanical properties of irradiated murine mammary fat pads (MFPs) and developed ECM hydrogels from decellularized tissues (dECM) to assess the effects of RT-induced ECM changes on breast cancer cell behavior. Irradiated MFPs were characterized by increased ECM deposition and fiber density compared to unirradiated controls, which may provide a platform for cell invasion and proliferation. ECM component changes in collagens I, IV, and VI, and fibronectin were observed following irradiation in both MFPs and dECM hydrogels. Encapsulated TNBC cell proliferation and invasive capacity was enhanced in irradiated dECM hydrogels. In addition, TNBC cells co-cultured with macrophages in irradiated dECM hydrogels induced M2 macrophage polarization and exhibited further increases in proliferation. Our study establishes that the ECM in radiation-damaged sites promotes TNBC invasion and proliferation as well as an immunosuppressive microenvironment. This work represents an important step toward elucidating how changes in the ECM after RT contribute to breast cancer recurrence.

cancer biology↗

bioRxiv2020

Bioengineering an in situ ovary (ISO) for fertility preservation

Female cancer patients who have undergone chemotherapy have an elevated risk of developing premature ovarian failure (POF) and infertility. Experimental approaches to treat iatrogenic infertility are evolving rapidly; however, there remain challenges and risks that have hindered clinical translation. To address these concerns, we developed an ovarian-specific extracellular matrix hydrogel to facilitate follicle delivery and establish an in situ ovary (ISO). We demonstrate sustainable engraftment, natural pregnancy and the birth of healthy pups after intraovarian microinjection of isolated exogenous follicles in a chemotherapy-induced POF mouse model. Our results suggest that the methods described could offer a minimally invasive alternative for the restoration of the ovarian reserve post-chemotherapy.

bioengineering↗