Biology subjects

Latifi, N.

Publications and source records attributed to Latifi, N..

6 recordsLinked to original sources

bioRxiv2025

Generation of Valvular Interstitial Cells from Human Pluripotent Stem Cells

Heart valves are living structures whose sophisticated functions are mediated by a specialized population of mesenchymal cells known as valvular interstitial cells (VICs). Given their central role in valve homeostasis, VICs represent a promising cell population for studying heart valve diseases and developing novel therapies to treat them. Here, we describe a strategy for generating VICs from human pluripotent stem cells (hPSCs) by stage-specific manipulation of developmental signalling pathways. Our results demonstrate that hPSC-derived VICs show a high transcriptional similarity to primary human fetal VICs and can secrete key proteins of the valve extracellular matrix. We further investigate the heterogeneity of hPSC-derived VICs and identify two major subpopulations with distinct molecular and functional properties, mirroring the cellular diversity observed in vivo. Finally, we utilize an in vitro model of Noonan syndrome to demonstrate that hPSC-derived VICs can accurately recapitulate key aspects of valve disease. Collectively, these findings provide a reproducible method for the scaled generation of bona fide hPSC-derived VICs and establish their utility in disease modelling and tissue engineering applications. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABS- We established a robust platform to generate bona fide valvular interstitial cells (VICs) from human pluripotent stem cells (hPSCs), recapitulating native VIC identity and function. - We delineated signaling pathways that promote the development of two distinct VIC subsets and identified a surface marker to distinguish between them. What are the clinical implications?- A renewable, human-specific source of VICs enables precise mechanistic studies of valve development and disease that are not possible with limited surgical specimens or animal models. - This platform creates opportunities for therapeutic applications, including drug discovery and tissue engineering approaches for valve repair.

cell biology↗

bioRxiv2025

Biomimetic biaxial mechanical properties enhance hemodynamic performance and prevent adverse tissue remodelling in tissue-engineered heart valves

Heart valve tissue engineering holds the promise of providing an unlimited supply of heart valve replacements for patients with valvular heart disease. While tissue-engineered heart valves show promising performance in the short term, regurgitation due to fibrotic leaflet shortening remains a persistent limitation in most cases. Here we tested the hypothesis that engineering heart valves with native biaxial mechanical properties would mitigate adverse tissue remodeling in vitro. Melt electrowriting and hydrogel casting were used to generate four types of tissue-engineered heart valves with combinatorial biomimetic or non-biomimetic mechanical properties in the radial and circumferential direction of the heart valves. The heart valves were subject to pulmonary hemodynamic conditions in a pulse duplicator bioreactor, and their tissue remodelling, including cell phenotype and orientation and extracellular matrix properties, was investigated. The results showed that tissue-engineered heart valves with native mechanical properties, particularly in the radial direction, outperformed those with non-physiological mechanics in hemodynamic function, maintaining quiescent cell phenotype and cell orientation, and avoiding fibrosis. This study, for the first time, elucidates the impact of native mechanical properties on the performance of tissue- engineered heart valves and their cell and extracellular matrix homeostasis.

bioengineering↗

bioRxiv2024

Adverse structural and mechanical remodelling of main pulmonary artery in experimental pulmonary arterial hypertension is associated with impaired right ventricle-pulmonary artery coupling and function

RationaleCoupling between right ventricular function and the pulmonary vasculature determines outcomes in pulmonary arterial hypertension. The mechanics of the main pulmonary artery is an important but understudied determinant of right ventricular-pulmonary artery coupling. ObjectivesTo investigate the histology and mechanics of the pulmonary artery in relationship to right ventricular remodeling, mechanics, hemodynamics and coupling in experimental pulmonary arterial hypertension. MethodsIn a sugen+hypoxia rat model of pulmonary arterial hypertension, right ventricular hemodynamics were assessed by conductance catheters. Active tension-strain curves were generated using echocardiography. Main pulmonary artery and right ventricle free-wall were harvested to determine their macro- and micro-structure, composition, and mechanical properties. Comprehensive multivariate analyses elucidated relationships between pulmonary artery and right ventricle mechanics, structure and coupling. Measurements and Main ResultsPulmonary hypertensive main pulmonary arteries developed fibrosis relative to healthy controls, as did right ventricles, which also hypertrophied, with re-orientation of muscle fibres toward a tri-layer architecture reminiscent of normal left ventricular architecture. Increased glycosaminoglycan deposition and increased collagen-to-elastin ratio in the pulmonary artery; and increased collagen, as well as hypertrophy and reorganization of myofibers in the right ventricle, led to increased stiffness. This increase in stiffness was more pronounced in the longitudinal direction in the high- and low-strain regime for the pulmonary artery and right ventricle, respectively, causing increased mechanical anisotropy. Main pulmonary artery stiffening correlated significantly with right ventricular tissue mechanical remodelling and reduced systolic performance, cardiac output and right ventricle-pulmonary artery coupling. ConclusionsCompositional, structural, and mechanical changes in the main pulmonary artery correlate with adverse right ventricular remodeling, mechanics, function and coupling in pulmonary arterial hypertension. Therefore, increasing mechanical compliance of the large pulmonary arteries may be an important and novel therapeutic strategy for mitigating right ventricular failure.

physiology↗

bioRxiv2023

Precise and efficient C-to-U RNA Base Editing with SNAP-CDAR-S

Site-directed RNA base editing enables the transient and dosable change of genetic information and represents a recent strategy to manipulate cellular processes, paving ways to novel therapeutic modalities. While tools to introduce adenosine-to-inosine changes have been explored quite intensively, the engineering of precise and programmable tools for cytidine-to-uridine editing is somewhat lacking behind. Here we demonstrate that the cytidine deaminase domain evolved from the ADAR2 adenosine deaminase, taken from the RESCUE-S tool, provides very efficient and highly programmable editing when changing the RNA targeting mechanism from Cas13-based to SNAP-tag-based. Optimization of the guide RNA chemistry further allowed to dramatically improve editing yields in the difficult-to-edit 5-CCN sequence context thus improving the substrate scope of the tool. Regarding editing efficiency, SNAP-CDAR-S outcompeted the RESCUE-S tool clearly on all tested targets, and was highly superior in perturbing the {beta}-catenin pathway. NGS analysis showed similar, moderate global off-target A-to-I and C-to-U editing for both tools.

molecular biology↗

bioRxiv2022

Non-invasive quantification of contractile dynamics in cardiac cells, spheroids and organs-on-a-chip using high frequency ultrasound

Cell-based models that mimic in vivo heart physiology are poised to make significant advances in cardiac disease modeling and drug discovery. In these systems, cardiomyocyte (CM) contractility is an important functional metric, but current measurement methods are inaccurate, low-throughput, or require complex set-ups. To address this need, we developed a standalone non-invasive, label-free ultrasound technique operating at 40-200 MHz to measure the beat rate, beat rhythm, and force of contraction of cardiac models, ranging from single adult CMs to 3D microtissue constructs in standard cell culture formats. The high temporal resolution of 1000 fps resolved the beat profile of single mouse CMs paced at up to 9 Hz, revealing limitations of lower speed optical based measurements to resolve beat kinetics or characterize aberrant beats. Coupling of ultrasound with traction force microscopy enabled the measurement of CM longitudinal modulus and facile estimation of adult mouse CM contractile forces of 2.34 {+/-} 1.40 N, comparable to more complex measurement techniques. Similarly, measurements of beat rate, rhythm, and drug responses of CM spheroid and microtissue models were demonstrated. In conclusion, ultrasound can be used for the rapid characterization of CM contractile function in a wide range of commonly-studied configurations ranging from single cells to 3D tissue constructs using standard well plates, with applications in cardiac drug discovery and cardiotoxicity evaluation.

bioengineering↗

bioRxiv2017

Modified hCFTR mRNA restores normal lung function in a mouse model of cystic fibrosis

Being a classic monogenic disease, gene therapy has always been a promising therapeutic approach for Cystic Fibrosis (CF). However, numerous trials using DNA or viral vectors encoding the correct protein resulted in a general low efficacy. In the last years, chemically modified messenger RNA (cmRNA) has been proven to be a highly potent, pulmonary effective drug. We thus explored the expression of human (h)CFTR encoded by hCFTR cmRNA in vitro, analyzed by flow cytometry and Western Blot and its function with a YFP assay. Very similar effects could be observed in vivo when hCFTR cmRNA was assembled with Chitosan-coated PLGA to nanoparticles (NPs) and intratracheally (i.t.) or intravenously (i.v) injected, the latter one as an alternative administration route to circumvent the clogged airways of CF patients. This significantly improved lung function, which suggests that hCFTR cmRNA-NPs are a promising therapeutic option for CF patients independent of their CFTR genotype.

genetics↗