Biology subjects

Neiman, G.

Publications and source records attributed to Neiman, G..

4 recordsLinked to original sources

bioRxiv2025

A cardiac microphysiological system for screening lipid nanoparticle/mRNA complexes predicts in vivo efficacy for heart transfection

Lipid nanoparticle (LNP)/mRNA complexes have tremendous potential for treating cardiac diseases but lack the transfection efficiency required for successful heart therapeutics. A challenge preventing the development of cardiac LNPs is the lack of in vitro screening platforms that maximize transfection and predict efficacy. Here, we demonstrate that a phenotypic cardiac microphysiological system (MPS), constructed from a human induced pluripotent stem cell cardiomyocytes (hiPSC-CM) Cre-reporter line, can identify LNP/mRNA complexes that diffuse efficiently within 3D cardiac micromuscles and transfect cardiomyocytes with high efficiency. Successful LNP formulations contained an acid-degradable PEG (ADP)-lipid, where ADP-LNPs containing 10% PEG had enhanced diffusion and gene editing efficiency in the cardiac MPS. The in vivo delivery of LNP/mRNA complexes, including luciferase and CRE mRNA, into Ai6 mice confirmed the cardiac MPS screening outcomes. It revealed that ADP-LNPs achieved notably superior transfection in the heart with reduced off-target liver uptake compared to a standard LNP formulation. The cardiac MPS showed strong LNP transfection in vitro and pinpointed a promising formulation for in vivo mRNA delivery to the heart.

bioengineering↗

bioRxiv2025

Pillar arrays as tunable interfacial barriers for microphysiological systems

We report on the design and fabrication of a novel circular pillar array as an interfacial barrier for microfluidic microphysiological systems (MPS). Traditional barrier interfaces, such as porous membranes and microchannel arrays, present limitations due to inconsistent pore size, complex fabrication and device assembly, and lack of tunability using a scalable design. Our pillar array overcomes these limitations by providing precise control over pore size, porosity, and hydraulic resistance through simple modifications of pillar dimensions. Serving as an interface between microfluidic compartments, it facilitates cell aggregation for tissue formation and acts as a tunable diffusion barrier that mimics diffusion in vivo. We demonstrate the utility of barrier design to engineer physiologically relevant cardiac microtissues and a heterotypic model with vasculature within the device. Its tunable properties offer significant potential for drug screening/testing and disease modeling, enabling comparisons of drug permeability and cell migration in MPS tissue with or without vasculature.

bioengineering↗

bioRxiv2020

Downregulation of E-cadherin in pluripotent stem cells triggers partial EMT

Epithelial to mesenchymal transition (EMT) is a critical cellular process that has been well characterized during embryonic development and cancer metastasis and it also is implicated in several physiological and pathological events including embryonic stem cell differentiation. During early stages of differentiation, human embryonic stem cells pass through EMT where deeper morphological, molecular and biochemical changes occur. Though initially considered as a decision between two states, EMT process is now regarded as a fluid transition where cells exist on a spectrum of intermediate states. In this work, using a CRISPR interference system in human embryonic stem cells, we describe a molecular characterization of the effects of downregulation of E-cadherin, one of the main initiation events of EMT, as a unique start signal. Our results suggest that the decrease and delocalization of E-cadherin causes an incomplete EMT where cells retain their undifferentiated state while expressing several characteristics of a mesenchymal-like pheno-type. Namely, we found that E-cadherin downregulation induces SNAI1 and SNAI2 upregulation, promotes MALAT1 and LINC-ROR downregulation, modulates the expression of tight junction occludin 1 and gap junction connexin 43, increases human embryonic stem cells migratory capacity and delocalize b-catenin. Altogether, we believe our results provide a useful tool to model the molecular events of an unstable intermediate state and further identify multiple layers of molecular changes that occur during partial EMT.

cell biology↗

bioRxiv2019

Analysis of the expression of PIWI-interacting RNAs during cardiac differentiation of human pluripotent stem cells

PIWI-interacting RNAs (piRNAs) are a class of non-coding RNAs initially thought to be restricted almost exclusively to germ line cells. In recent years, accumulating evidence has demonstrated that piRNAs are actually expressed in somatic cells like pluripotent, neural, cardiac and even cancer cells. However, controversy still remains around the existence and function of somatic piRNAs. Using small RNA-seq samples from H9 pluripotent stem cells differentiated to mesoderm progenitors and cardiomyocytes we identified the expression of 447 piRNAs, of which 241 were detected in pluripotency, 218 in mesoderm and 171 in cardiac cells. The majority of them originated from the sense strand of protein coding and lncRNAs genes in all stages of differentiation, though no evidences for secondary piRNAs (ping-pong loop) were found. Genes hosting piRNAs in cardiac samples were related to critical biological processes in the heart, like contraction and cardiac muscle development. Our results indicate that somatic piRNAs might have a role in fine-tuning the expression of genes involved in the differentiation of pluripotent cells to cardiomyocytes.

molecular biology↗