Biology subjects

Hepokoski, M.

Publications and source records attributed to Hepokoski, M..

3 recordsLinked to original sources

bioRxiv2026

An Improved Manufacturing Method for Infusible Extracellular Matrix Materials to Enable Efficient Scale-Up, Improved Efficacy, and Clinical Translation

Decellularized extracellular matrix (ECM) materials are a popular choice for tissue engineering and regenerative medicine applications due to their multifaceted bioactive capabilities arising from their heterogenous composition. For minimally invasive delivery, infusible ECM (iECM) was developed through fractionation of digested decellularized ECM, allowing the material to be safely delivered intravascularly. iECM localizes to permeable vasculature in inflamed tissues and exerts immunomodulatory and pro-reparative effects with proof-of-concept already demonstrated in multiple preclinical models including myocardial infarction (MI) and multiple organ dysfunction syndrome (MODS). However, one major limitation of iECM is the steps required for manufacturing, involving centrifugation, dialysis/lyophilization, and filtration (C-D-F). These steps limit manufacturing output and iECM concentration, and require significant human handling, limiting compliance with current good manufacturing practices (cGMP). To overcome these challenges, we developed a method for manufacturing iECM that utilizes depth filtration and tangential flow filtration (DF-TFF), which reduces manufacturing time, allows for increased iECM concentration, and reduces human manipulation of material, improving translatability and scalability of iECM materials. Based on multiple material characterization methods, we determined that iECM made with DF-TFF was comparable to iECM made with C-D-F. By increasing iECM concentration through this manufacturing method, we demonstrate a dose dependent response in an acute MI porcine model and a mouse MODS model. Finally, DF-TFF enabled timely production of iECM from alternative tissue sources. Altogether, DF-TFF allows for improvements in production time, scale-up, cGMP compliance, and increased dose through higher concentration, paving the way for future clinical translation as well new preclinical studies.

bioengineering↗

bioRxiv2021

Profiling Transcription Initiation in Peripheral Leukocytes Reveals Severity-Associated Cis-Regulatory Elements in Critical COVID-19

The contribution of transcription factors (TFs) and gene regulatory programs in the immune response to COVID-19 and their relationship to disease outcome is not fully understood. Analysis of genome-wide changes in transcription at both promoter-proximal and distal cis-regulatory DNA elements, collectively termed the active cistrome, offers an unbiased assessment of TF activity identifying key pathways regulated in homeostasis or disease. Here, we profiled the active cistrome from peripheral leukocytes of critically ill COVID-19 patients to identify major regulatory programs and their dynamics during SARS-CoV-2 associated acute respiratory distress syndrome (ARDS). We identified TF motifs that track the severity of COVID- 19 lung injury, disease resolution, and outcome. We used unbiased clustering to reveal distinct cistrome subsets delineating the regulation of pathways, cell types, and the combinatorial activity of TFs. We found critical roles for regulatory networks driven by stimulus and lineage determining TFs, showing that STAT and E2F/MYB regulatory programs targeting myeloid cells are activated in patients with poor disease outcomes and associated with single nucleotide genetic variants implicated in COVID-19 susceptibility. Integration with single-cell RNA-seq found that STAT and E2F/MYB activation converged in specific neutrophils subset found in patients with severe disease. Collectively we demonstrate that cistrome analysis facilitates insight into disease mechanisms and provides an unbiased approach to evaluate global changes in transcription factor activity and stratify patient disease severity.

genomics↗

bioRxiv2020

SARS-CoV-2 Spike Protein Impairs Endothelial Function via Downregulation of ACE2

Coronavirus disease 2019 (COVID-19) includes the cardiovascular complications in addition to respiratory disease. SARS-CoV-2 infection impairs endothelial function and induces vascular inflammation, leading to endotheliitis. SARS-CoV-2 infection relies on the binding of Spike glycoprotein (S protein) to angiotensin converting enzyme 2 (ACE2) in the host cells. We show here that S protein alone can damage vascular endothelial cells (ECs) in vitro and in vivo, manifested by impaired mitochondrial function, decreased ACE2 expression and eNOS activity, and increased glycolysis. The underlying mechanism involves S protein downregulation of AMPK and upregulation of MDM2, causing ACE2 destabilization. Thus, the S protein-exerted vascular endothelial damage via ACE2 downregulation overrides the decreased virus infectivity.

pathology↗