Human Cytomegalovirus miRNAs Regulate TGF-β to Mediate Myelosuppression while Maintaining Viral Latency in CD34+ Hematopoietic Progenitor Cells

Abstract

Highlights d Latent HCMV infection of stem cells induces the myelosuppressive cytokine TGF-b d HCMV miR-US5-2 targets the transcriptional repressor NAB1 to mediate TGF-b expression d HCMV miR-UL22A downregulates SMAD3 to block TGF-b signaling in the infected cell d Blocking TGF-b signaling is critical for HCMV latency and genome maintenance

Human Cytomegalovirus Infection Suppresses CD34+ Progenitor Cell Engraftment in Humanized Mice

“…Briefly, CD34 + HPCs were infected with HCMV strain TB40/E (MOI 3) purified by FACS for CD34 + GFP + HPCs and cultured for 14 days in Methocult H4434. As shown in Figure 1A, HCMV infection suppressed myeloid (CFU-GM reduced by 43%, and CFUGEMM reduced by 78%) but not erythroid (CFU-E and BFU-E) colony formation compared to mock, which is comparable with previously published results from our laboratory and others [2][3][4][5][6].…”

“…Primary CD34 + HPCs were thawed (with an average viability of 80% post-thaw) and recovered overnight in stem cell media. HPCs were then infected with HCMV, FACS-isolated, and plated for analysis of colony formation ability as previously described [6]. CD34 + HPCs were infected with wild-type HCMV (strain: TB40/E-GFP) or mock-infected for 24-48 hrs.…”

“…Early studies using in vitro systems indicated that HCMV infection of CD34 + hematopoietic progenitor cells (HPCs) alters myeloid development [2][3][4][5]. We recently published that latent HCMV infection of CD34 + HPCs induces the secretion of TGF-β that is responsible for virus-mediated myelosuppression [6]. Even though these results provide relevant insights into the mechanism(s) for how the latent HCMV infection of a minor population of CD34 + HPCs in the bone marrow induces global myelosuppression in HSCT patients, the strict species specificity of HCMV and the lack of surrogate animal models have precluded the in vivo validation of these findings as well as the development of preventive strategies that can target latently infected cells.…”

Human Cytomegalovirus Infection Suppresses CD34+ Progenitor Cell Engraftment in Humanized Mice

“…responsible for virus-mediated myelosuppression [6]. Even though these results provide relevant insights into the mechanism(s) for how the latent HCMV infection of a minor population of CD34 + HPCs in the bone marrow induces global myelosuppression in HSCT patients, the strict species specificity of HCMV and the lack of surrogate animal models have precluded the in vivo validation of these findings as well as the development of preventive strategies that can target latently infected cells.…”

“…Primary CD34 + HPCs were thawed and recovered overnight in stem cell media. HPCs were then infected with HCMV, FACS isolated, and plated for analysis of colony formation ability as previously described [6]. CD34 + HPCs were infected with wild-type HCMV (strain: TB40/E-GFP) or Mock-infected for 24-48hrs.…”