The National Heart, Lung, and Blood Institute-funded Production Assistance for Cellular Therapies (PACT) program: Eighteen years of cell therapy.

The Production Assistance for Cellular Therapies (PACT) Program, is funded and supported by the US Department of Health and Human Services' National Institutes of Health (NIH) National Heart Lung and Blood Institute (NHLBI) to advance development of somatic cell and genetically modified cell therapeutics in the areas of heart, lung, and blood diseases. The program began in 2003, continued under two competitive renewals, and ended June 2021. PACT has supported cell therapy product manufacturing, investigational new drug enabling preclinical studies, and translational services, and has provided regulatory assistance for candidate cell therapy products that may aid in the repair and regeneration of damaged/diseased cells, tissues, and organs.

Ebola in the United States.

The ongoing epidemic of Ebola virus in West Africa and attendant cases described in other parts of the world has focused attention on this heretofore rare disease. In this brief opinion article, we provide a short primer on the epidemiology, pathogenesis, clinical manifestations, US-based hospital preparedness, vaccine and therapy development, and control of Ebola virus disease for noninfectious disease physicians.

Attenuated expression of interferon-β and interferon-λ1 by human alternatively activated macrophages.

Macrophages can be polarized into classically (CAM) or alternatively (AAM) activated macrophages with IFN-γ or IL-4, respectively. CAM are associated with type 1 immune responses and are implicated in autoimmunity; AAM are associated with type 2 responses and are implicated in allergic diseases. An impediment in investigating macrophage biology using primary human monocyte derived macrophages is the wide inter-donor heterogeneity and the limited quantity of cells that survive in vitro polarization.

Sequential proteolytic processing of an interferon-alpha receptor subunit by TNF-alpha converting enzyme and presenilins.

It is well established that interferons trigger tyrosine-kinase-dependent signaling via JAK kinases and STAT transcription factors. However, we have observed both IFNaR2 receptor cleavage and functional activity of the liberated intracellular domain (ICD), suggesting that interferon-alpha (IFN-alpha) can also signal via regulated intramembrane proteolysis (RIP), an evolutionarily conserved mechanism of receptor-mediated signaling. Sequential cleavage of the receptor ectodomain and transmembrane domain is a hallmark of the most common class of RIP.

Nuclear transit of the intracellular domain of the interferon receptor subunit IFNaR2 requires Stat2 and Irf9.

Regulated intramembrane proteolysis (RIP) is the primary signaling mechanism for some receptors, such as Notch and the amyloid precursor protein. In addition, some receptor type tyrosine kinases, such as HER4, are able to signal via both kinase activation and regulated receptor proteolysis. Previously, we showed that the IFNaR2 subunit of the type I interferon receptor can be cleaved in a two step process that resembles RIP and that the IFNaR2 intracellular domain (IFNaR2-ICD) can mediate gene transcription in a Stat2 dependent manner.

Intracellular domain of the IFNaR2 interferon receptor subunit mediates transcription via Stat2.

We recently demonstrated that IFNaR2, a subunit of the interferon receptor, can be proteolytically cleaved in response to interferon-alpha and other activators of protein kinase C. Cleavage occurs at multiple sites, via a mechanism similar to that employed by Notch and the Alzheimer's precursor protein, and releases the intracellular domain (ICD). In this study, we demonstrate that the IFNaR2 ICD, when fused to the yeast Gal4 DNA binding domain (Gal4DBD) selectively modulates transcription of four different promoters under the control of Gal4 upstream activating sequences.

Regulated proteolysis of the IFNaR2 subunit of the interferon-alpha receptor.

The type I interferons (IFNs) bind surface receptors, induce JAK kinases and activate STAT transcription factors to stimulate the transcription of genes downstream of IFN-stimulated response elements (ISREs). In this study, we demonstrate that IFNaR2, a subunit of the type I IFN receptor, is proteolytically cleaved in a regulated manner. Immunoblotting shows that multi-step cleavage occurs in response to phorbol ester (PMA) and IFN-alpha, generating both a transmembrane 'stub' and the intracellular domain (ICD), similar to Notch proteolysis.