Preparation and quantification of pseudotyped retroviral vector

Induced Pluripotent Stem Cells from Ovarian Tissue

Yamanaka and colleagues revolutionized stem cell biology and regenerative medicine by observing that somatic cells can be reprogrammed into pluripotent stem cells. Evidence indicates that induced pluripotent stem (iPS) cells retain epigenetic memories that bias their spontaneous differentiation into the originating somatic cell type, therefore epigenetic memory may be exploited to improve tissue specific regeneration. We recently showed that iPS cells reprogrammed from ovarian granulosa cells using mouse and human tissue overwhelmingly differentiate homotypically into ovarian steroidogenic and primordial germ cells. Herein we detail a protocol for the culture of human ovarian granulosa cells. We review approaches for reprogramming human ovarian granulosa cells into iPS cells. Standard methods to induce pluripotency are outlined, concentrating on integrative retroviruses. Additionally, alternative protocols for lentivirus and Sendai virus are provided. Each approach has inherent limitations, such as reprogramming efficiency, insertional mutagenesis, and partial reprogramming. Major advances continue to be made in somatic cell reprogramming to identify an optimal approach and utilization in cell-based therapies. © 2017 by John Wiley & Sons, Inc.

Sox-9 facilitates differentiation of adipose tissue-derived stem cells into a chondrocyte-like phenotype in vitro

The purpose of this study is to test whether ectopic expression of Sox-9 can induce adipose tissue-derived stem cells (ASCs) to function as real nucleus pulposus (NP) cells in vitro. Adenoviral vectors expressing Sox-9 were reported to infect the chondroblastic and human disc cells, which resulted in increased Sox-9 and type II collagen production. ASCs were isolated from rat inguinal adipose pad, characterized, and transduced in vitro with a retroviral vector encoding the Sox-9 gene. Sox-9-engineered ASCs (ASCs/Sox-9) were induced for the chondrocyte-like cell differentiation by 3D cultured in alginate beads and TGF-β3 for 2 weeks. Expression of exogenous Sox-9 protein was detected. Type II collagen and Aggrecan gene expressions of induced ASCs/Sox-9 were measured using real-time PCR; proteoglycans expressions were measured by checking the glycosaminoglycan content and type II collagen production by enzyme-linked immunosorbent assay. Isolated ASCs were CD 29(+) /CD44(+) /C-Kit(-) /Lin(-) /CD34(-) /CD45(-) . ASCs/Sox-9 expressed marked increase in exogenous Sox-9 protein. After induction, type II collagen gene expression was sevenfold higher in mRNA levels, with an approximately twofold increase in protein levels of ASCs/Sox-9 compared to ASCs. Type II collagen and proteoglycan productions were significantly increased in the ASCs/Sox-9 compared to the ASCs. In addition, co-culture of induced ASCs/Sox-9 with matured NP cells resulted in enhanced increase in proteoglycan and type II collagen production. Constitutive retroviral expression of Sox-9 could efficiently induce ASCs differentiation into chondrocyte-like cells. This novel approach may provide a practicable system for a simple and rapid differentiation of ASCs into chondrocyte-like cells which may be potentially used as a stem cell-based therapeutic tool for the treatment of degenerative disc diseases.

Impaired infectivity of ritonavir-resistant HIV is rescued by heat shock protein 90AB1

Certain ritonavir resistance mutations impair HIV infectivity through incomplete Gag processing by the mutant viral protease. Analysis of the mutant virus phenotype indicates that accumulation of capsid-spacer peptide 1 precursor protein in virus particles impairs HIV infectivity and that the protease mutant virus is arrested during the early postentry stage of HIV infection before proviral DNA synthesis. However, activation of the target cell can rescue this defect, implying that specific host factors expressed in activated cells can compensate for the defect in ritonavir-resistant HIV. This ability to rescue impaired HIV replication presented a unique opportunity to identify host factors involved in postentry HIV replication, and we designed a functional genetic screen so that expression of a given host factor extracted from activated T cells would lead directly to its discovery by rescuing mutant virus replication in nonactivated T cells. We identified the cellular heat shock protein 90 kDa α (cytosolic), class B member 1 (HSP90AB1) as a host factor that can rescue impaired replication of ritonavir-resistant HIV. Moreover, we show that pharmacologic inhibition of HSP90AB1 with 17-(allylamino)-17-demethoxygeldanamycin (tanespimycin) has potent in vitro anti-HIV activity and that ritonavir-resistant HIV is hypersensitive to the drug. These results suggest a possible role for HSP90AB1 in postentry HIV replication and may provide an attractive target for therapeutic intervention.