Go2 G protein mediates galanin inhibitory effects on insulin release from pancreatic ß cells.

The neuropeptide galanin regulates numerous physiological activities in the body, including feeding and metabolism, learning and memory, nociception and spinal reflexes, and anxiety and related behaviors. Modulation of blood glucose levels by suppressing insulin release was the first reported activity for galanin. This inhibition was mediated by one or more pertussis toxin-sensitive G proteins of the G(i/o) subfamily. However, the molecular identities of the specific G protein(s) and intracellular effectors have not been fully revealed. Recently, we demonstrated that mice lacking G(o)2, but not other members of the G(i/o) protein family, secrete more insulin than controls upon glucose challenge, indicating that G(o)2 is a major transducer for the inhibitory regulation of insulin secretion. In this study, we investigated galanin signaling mechanisms in ß cells using cell biological and electrophysiological approaches. We found that islets lacking G(o)2, but not other G(i/o) proteins, lose the inhibitory effect of galanin on insulin release. Potentiation of ATP-sensitive potassium (K(ATP)) and inhibition of calcium currents by galanin were disrupted by anti-G(o)2α antibodies. Galanin actions on K(ATP) and calcium currents were completely lost in G(o)2(-/-) ß cells. Furthermore, the hyperglycemic effect of galanin is also blunted in G(o)2(-/-) mice. Our results demonstrate that G(o)2 mediates the inhibition of insulin release by galanin by regulating both K(ATP) and Ca(2+) channels in mice. Our findings provide insight into galanin's action in glucose homeostasis. The results may also be relevant to the understanding of galanin signaling in other biological systems, especially the central nervous system.

HSF4 mutation p.Arg116His found in age-related cataracts and in normal populations produces childhood lamellar cataract in transgenic mice.

The p.Arg116His mutation in the heat shock transcription factor-4 (HSF4) has been associated with age-related cataracts, but it is also seen in 2% of the normal population, indicating either reduced penetrance or that the normal subjects were not old enough to express the phenotype. Based on the proximity of p.Arg116His to two known mutations in the DNA-binding domain of HSF4, namely, p.Leu114Pro and p.Arg119Cys, which segregate with childhood lamellar cataract, we tested the possibility that this phenotype may have been missed by the ophthalmologist and/or that it did not spread to the visual axis so as to affect vision significantly. Here, we demonstrate via BAC (bacterial artificial chromosome) transgenesis that p.Arg116His recreates the childhood lamellar cataract in mice suggesting that incomplete penetrance associated with early cataracts may not be an absence but a limitation of the detection of the phenotype.

Transgenic overexpression of hexose-6-phosphate dehydrogenase in adipose tissue causes local glucocorticoid amplification and lipolysis in male mice.

The prereceptor activation of glucocorticoid production in adipose tissue by NADPH-dependent 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) has emerged as a potential mechanism in the pathogenesis of visceral obesity and metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) is an endoplasmic reticulum lumen-resident enzyme that generates cofactor NADPH and thus mediates 11ß-HSD1 activity. To determine the role of adipose H6PDH in the prereceptor modulation of 11ß-HSD1 and metabolic phenotypes, we generated a transgenic (Tg) mouse model overexpressing H6PDH under the control of the enhancer-promoter region of the adipocyte fatty acid-binding protein (aP2) gene (aP2/H6PDH Tg mice). Transgenic aP2/H6PDH mice exhibited relatively high expression of H6PDH and elevated corticosterone production with induction of 11ß-HSD1 activity in adipose tissue. This increase in corticosterone production in aP2-H6PDH Tg mice resulted in mild abdominal fat accumulation with induction of C/EBP mRNA expression and slight weight gain. Transgenic aP2/H6PDH mice also exhibited fasting hyperglycemia and glucose intolerance with insulin resistance. In addition, the aP2/H6PDH Tg mice have elevated circulating free fatty acid levels with a concomitant increased adipose lipolytic action associated with elevated HSL mRNA and Ser(660) HSL phosphorylation within abdominal fat. These results suggest that increased H6PDH expression specifically in adipose tissue is sufficient to cause intra-adipose glucocorticoid production and adverse metabolic phenotypes. These findings suggest that the aP2/H6PDH Tg mice may provide a favorable model for studying the potential impact of H6PDH in the pathogenesis of human metabolic syndrome.

Augmented glucose-induced insulin release in mice lacking G(o2), but not G(o1) or G(i) proteins.

Insulin secretion by pancreatic ß cells is a complex and highly regulated process. Disruption of this process can lead to diabetes mellitus. One of the various pathways involved in the regulation of insulin secretion is the activation of heterotrimeric G proteins. Bordetella pertussis toxin (PTX) promotes insulin secretion, suggesting the involvement of one or more of three G(i) and/or two G(o) proteins as suppressors of insulin secretion from ß cells. However, neither the mechanism of this inhibitory modulation of insulin secretion nor the identity of the G(i/o) proteins involved has been elucidated. Here we show that one of the two splice variants of G(o), G(o2), is a key player in the control of glucose-induced insulin secretion by ß cells. Mice lacking G(o2)α, but not those lacking α subunits of either G(o1) or any G(i) proteins, handle glucose loads more efficiently than wild-type (WT) mice, and do so by increased glucose-induced insulin secretion. We thus provide unique genetic evidence that the G(o2) protein is a transducer in an inhibitory pathway that prevents damaging oversecretion of insulin.

Reassessing the role of APOBEC3G in human immunodeficiency virus type 1 infection of quiescent CD4+ T-cells.

HIV-1 is restricted for infection of primary quiescent T-cells. After viral entry, reverse transcription is initiated but is not completed. Various hypotheses have been proposed for this cellular restriction including insufficient nucleotide pools and cellular factors, but none have been confirmed as the primary mechanism for restriction. A recent study by Chiu et al. implicates APOBEC3G, an anti-retroviral cytidine deaminase, as the cellular restriction factor. Here, we attempted to confirm these findings using the same strategy as reported by Chiu et al. of siRNA targeting knock-down of APOBEC3G expression. In contrast to the published study, our results do not support a role for APOBEC3G in restriction of HIV-1 in quiescent CD4+ T-cells. In our study, we tested the same siRNA as reported by Chiu et al. as well as two additional siRNAs targeting APOBEC3G, one of which showed 2-fold greater knock-down of APOBEC3G mRNA. However, none of the three siRNAs tested had a discernable effect on enhancing infection by HIV-1 in quiescent CD4+ T-cells. Therefore, we conclude that the primary mechanism of HIV-1 restriction in quiescent CD4+ T-cells remains to be elucidated.

Regulated expression of the Ras effector Rin1 in forebrain neurons.

The Ras effector Rin1 is induced concomitant with synaptogenesis in forebrain neurons, where it inhibits fear conditioning and amygdala LTP. In epithelial cells, lower levels of Rin1 orchestrate receptor endocytosis. A 945 bp Rin1 promoter fragment was active in hippocampal neurons and directed accurate tissue-specific and temporal expression in transgenic mice. Regulated expression in neurons and epithelial cells was mediated in part by Snail transcriptional repressors: mutation of a conserved Snail site increased expression and endogenous Snai1 was detected at the Rin1 promoter. We also describe an element closely related to, but distinct from, the consensus site for REST, a master repressor of neuronal genes. Conversion to a consensus REST sequence reduced expression in both cell types. These results provide insight into regulated expression of a neuronal Ras effector, define a promoter useful in telencephalic neuron studies, and describe a novel REST site variant directing expression to mature neurons.

Role of TH17 Responses in Increasing Herpetic Keratitis in the Eyes of Mice Infected with HSV-1.

Purpose: TH17 cells play an important role in host defense and autoimmunity yet very little is known about the role of IL17 in herpes simplex virus (HSV)-1 infectivity. To better understand the relationship between IL17 and HSV-1 infection, we assessed the relative impact of IL17A-deficiency and deficiency of its receptors on HSV-1 responses in vivo. Methods: We generated IL17RA-/- and IL17RA-/-RC-/- mice in-house and infected them along with IL17A-/- and IL17RC-/- mice in the eyes with 2 × 105 PFU/eye of wild type (WT) HSV-1 strain McKrae. WT C57BL/6 mice were used as control. Virus replication in the eye, survival, corneal scarring (CS), angiogenesis, levels of latency-reactivation, and levels of CD8 and exhaustion markers (PD1, TIM3, LAG3, CTLA4, CD244, and CD39) in the trigeminal ganglia (TG) of infected mice were determined on day 28 postinfection. Results: No significant differences in virus replication in the eye, survival, latency, reactivation, and exhaustion markers were detected among IL17A-/-, IL17RA-/-, IL17RC-/-, IL17RA-/-RC-/-, and WT mice. However, mice lacking IL17 had significantly less CS and angiogenesis than WT mice. In addition, angiogenesis levels in the absence of IL17RC and irrespective of the absence of IL17RA were significantly less than in IL17A- or IL17RA-deficient mice. Conclusions: Our results suggest that the absence of IL17 protects against HSV-1-induced eye disease, but has no role in protecting against virus replication, latency, or reactivation. In addition, our data provide rationale for blocking IL17RC function rather than IL17A or IL17RA function as a key driver of HSV-1-induced eye disease.

Auxiliary trafficking subunit GJA1-20k protects connexin-43 from degradation and limits ventricular arrhythmias.

Connexin-43 (Cx43) gap junctions provide intercellular coupling, which ensures rapid action potential propagation and synchronized heart contraction. Alterations in Cx43 localization and reductions in gap junction coupling occur in failing hearts, contributing to ventricular arrhythmias and sudden cardiac death. Recent reports have found that an internally translated Cx43 isoform, GJA1-20k, is an auxiliary subunit for the trafficking of Cx43 in heterologous expression systems. Here, we have created a mouse model by using CRISPR technology to mutate a single internal translation initiation site in Cx43 (M213L mutation), which generates full-length Cx43, but not GJA1-20k. We found that GJA1M213L/M213L mice had severely abnormal electrocardiograms despite preserved contractile function, reduced total Cx43, and reduced gap junctions, and they died suddenly at 2 to 4 weeks of age. Heterozygous GJA1M213L/WT mice survived to adulthood with increased ventricular ectopy. Biochemical experiments indicated that cytoplasmic Cx43 had a half-life that was 50% shorter than membrane-associated Cx43. Without GJA1-20k, poorly trafficked Cx43 was degraded. The data support that GJA1-20k, an endogenous entity translated independently of Cx43, is critical for Cx43 gap junction trafficking, maintenance of Cx43 protein, and normal electrical function of the mammalian heart.

Human immunodeficiency virus type 1 Vpr binds to the N lobe of the Wee1 kinase domain and enhances kinase activity for CDC2.

Human immunodeficiency virus type 1 Vpr is a virion-associated accessory protein that has multiple activities within an infected cell. One of the most dramatic effects of Vpr is the induction of cell cycle arrest at the G(2)/M boundary, followed by apoptosis. This effect has implications for CD4(+) cell loss in AIDS. In normal cell cycle regulation, Wee1, a key regulator for G(2)-M progression, phosphorylates Tyr15 on Cdc2 and thereby blocks the progression of cells into M phase. We demonstrate that Vpr physically interacts with Wee1 at the N lobe of the kinase domain analogous to that present in other kinases. This interaction with Vpr enhances Wee1 kinase activity for Cdc2. Overexpression of Wee1 kinase-deficient mutants competes for Vpr-mediated cell cycle arrest, and deletion of the region of Wee1 that binds Vpr abrogates that competition. However, the Vpr mutants I74P and I81P, which fail to induce G(2) arrest, can bind to and increase the kinase activity of Wee1 to the same extent as wild-type Vpr. Therefore, we conclude that the binding of Vpr to Wee1 is not sufficient for Vpr to activate the G(2) checkpoint, and it may reflect an independent function of Vpr.

Inflammation is a key contributor to ovarian cancer cell seeding.

The incidence of ovarian cancer dramatically increases in early menopause but the factors contributing to cancer onset are unclear. Most ovarian cancers originate in the fallopian tube with subsequent implantation of malignant cells into the ovary. However, the events and conditions that lead to cancer cell implantation are unknown. To quantify which conditions are conducive to the seeding of cancer cells in an immunocompetent mouse model, we surgically implanted mouse ovarian cancer cells into the oviducts of syngeneic mice and simulated conditions associated with ovulatory wound repair, incessant ovulation, ovarian surface scarring, and aging. We found that the dominant site of cancer cell seeding was not the ovary but the nearby surgical wound site, which was associated with a strong and persistent inflammatory reaction. Conditions in the ovary associated with inflammation, such as acute ovulatory wound repair, active healing of the scarred ovarian surface, and mouse aging, contributed to increased seeding of the cancer cells to the surgical wound site and tissues surrounding the ovary. Changes in the ovary not accompanied by inflammation, such as completed ovulatory cycles and fully-healed scars on the ovarian surface, did not contribute to increased cancer cell seeding. We conclude that inflammation is the most likely mechanism by which ovulation and postmenopausal events contribute to the increased risk of ovarian cancer.

A Bacterial Artificial Chromosome Reporter System for Expression of the Human FOXP3 Gene in Mouse Regulatory T-Cells.

The transcription factor FOXP3 plays key roles in the development and function of regulatory T cells (Treg) capable of preventing and correcting immunopathology. There has been much interest in exploiting Treg as adoptive cell therapy in man, but issues of lack of nominal antigen-specificity and stability of FoxP3 expression in the face of pro-inflammatory cytokines have been a concern. In order to enable fundamental studies of human FOXP3 (hFOXP3) gene regulation and to provide preclinical tools to guide the selection of drugs that might modulate hFOXP3 expression for therapeutic purposes, we generated hFOXP3/AmCyan bacterial artificial chromosome (BAC) transgenic mice and transfectants, wherein hFOXP3 expression was read out as AmCyan expression. Using the transgenic mice, one can now investigate hFOXP3 gene expression under defined experimental conditions used for mouse Foxp3 (mFoxp3) studies. Here, we demonstrate that hFOXP3 gene expression in BAC transgenic mice is solely restricted to CD4+ T-cells, as for mFoxp3 gene expression, showing that hFOXP3 expression in Treg cells depends on fundamentally similar processes to mFoxp3 expression in these cells. Similarly, hFOXP3 expression could be observed in mouse T-cells through TCR stimulation in the presence of TGF-ß. These data suggest that, at least in part, cell type-specific human and mouse foxp3 gene expression is regulated by common regulatory regions which for the human, are located within the 110-kb human FOXP3 BAC DNA. To investigate hFOXP3 gene expression further and to screen potential therapeutics in modulating hFOXP3 gene expression in vitro, we also generated hFOXP3/AmCyan expression reporter cell lines. Using the reporter cells and transcription factor inhibitors, we showed that, just as for mFoxp3 expression, inhibitors of NF-κB, AP1, STAT5, Smad3, and NFAT also block hFOXP3 expression. hFOXP3 induction in the reporter cells was also TGF-ß dependent, and substantially enhanced by an mTOR inhibitor, Torin1. In both the reporter transgenic mice and cell lines, histone H4 molecules in the hFOXP3 promoter and enhancers located in human CNS1 and CNS2 regions were highly acetylated in natural Treg and TCR/TGF-ß-induced Treg, indicating hFOXP3 gene expression is regulated by mechanisms similar to those previously identified for the mFoxp3 gene.

Inhibition of lobuloalveolar development by FOXC1 overexpression in the mouse mammary gland.

The forkhead box transcription factor FOXC1 plays a critical role in embryogenesis and the development of many organs. Its mutations and high expression are associated with many human diseases including breast cancer. Although FOXC1 knockout mouse studies showed that it is not required for mammary gland development during puberty, it is not clear whether its overexpression alters normal mammary development in vivo. To address this question, we generated transgenic mice with mammary-specific FOXC1 overexpression. We report that transgenic FOXC1 overexpression suppresses lobuloalveologenesis and lactation in mice. This phenotype is associated with higher percentages of estrogen receptor-, progesterone receptor-, or ki67-positive mammary epithelial cells in the transgenic mice at the lactation stage. We also show that expression of the Elf5 transcription factor, a master regulator of mammary alveologenesis and luminal cell differentiation, is markedly reduced in mammary epithelial cells of transgenic mice. Likewise, levels of activated Stat5, another inducer of alveolar expansion and a known mediator of the Elf5 effect, are also lowered in those cells. In contrast, the cytokeratin 8-positive mammary cell population with progenitor properties is elevated in the transgenic mice at the lactation stage, suggesting inhibition of mammary cell differentiation. These results may implicate FOXC1 as a new important regulator of mammary gland development.

Purging Exhausted Virus-Specific CD8 T Cell Phenotypes by Somatic Cell Reprogramming.

Cytotoxic T cells are critical in controlling virus infections. However, continuous antigen stimulation and negative regulatory factors cause CD8 T cells to enter a dysfunctional state (T cell exhaustion), resulting in viral persistence. We hypothesized that the exhausted T cell state could be molecularly rejuvenated using a somatic cell reprogramming technology, which is technically able to convert any types of cells to induced pluripotent stem cells (iPSCs), to regenerate functional T cells capable of purging chronic infection. We generated a new mouse line (B6/129OKSM) in which every somatic cell contains four doxycycline-inducible reprogramming genes (Oct4, Klf4, Sox2, and c-Myc: OKSM), and infected them with lymphocytic choriomeningitis virus (LCMV) clone 13 to establish chronic infection. Exhausted LCMV-specific T cells isolated by flow sorting were successfully reprogrammed ex vivo into iPSCs in the presence of doxycycline. Upon injection into blastocysts and subsequent transfer into foster females, the reprogrammed cells differentiated into functional naive T cells that maintained their original antigen specificity. These results provide proof of concept that somatic cell reprogramming of exhausted T cells into iPSCs can erase imprints of their previous exhausted state and in turn regenerate functional virus-specific T cells.

CCR5 is a suppressor for cortical plasticity and hippocampal learning and memory.

Although the role of CCR5 in immunity and in HIV infection has been studied widely, its role in neuronal plasticity, learning and memory is not understood. Here, we report that decreasing the function of CCR5 increases MAPK/CREB signaling, long-term potentiation (LTP), and hippocampus-dependent memory in mice, while neuronal CCR5 overexpression caused memory deficits. Decreasing CCR5 function in mouse barrel cortex also resulted in enhanced spike timing dependent plasticity and consequently, dramatically accelerated experience-dependent plasticity. These results suggest that CCR5 is a powerful suppressor for plasticity and memory, and CCR5 over-activation by viral proteins may contribute to HIV-associated cognitive deficits. Consistent with this hypothesis, the HIV V3 peptide caused LTP, signaling and memory deficits that were prevented by Ccr5 knockout or knockdown. Overall, our results demonstrate that CCR5 plays an important role in neuroplasticity, learning and memory, and indicate that CCR5 has a role in the cognitive deficits caused by HIV.

Expression of the HSF4 DNA binding domain-EGFP hybrid gene recreates early childhood lamellar cataract in transgenic mice.

PURPOSE: The clinical management of cataracts in infancy involves surgical removal of the lens to ensure transmission of light to the retina, which is essential for normal neural development of the infant. This surgery, however, entails a lifelong follow-up and impaired vision. To our knowledge, no animal models recapitulate human lamellar opacities, the most prevalent form of early childhood cataracts. We present data on the recreation of the human lamellar cataract phenotype in transgenic mice. METHODS: Mutations in the DNA binding domain (DBD) of the heat shock transcription factor 4 (HSF4) are known to be associated with early childhood autosomal dominant lamellar cataract. We used bacterial artificial chromosome (BAC) transgenesis to express a hybrid gene: Hsf4 (DBD)-enhanced green fluorescent protein (EGFP), by recombineering EGFP sequences into the DBD of the Hsf4 gene, to interfere with the DNA binding properties of Hsf4. RESULTS: We recapitulated the human lamellar cataract, in its temporal as well as spatial presentation, within the transgenic mouse lens. This phenotype was reproduced faithfully using four different BACs, indicating that EGFP can be used to target transcription factor function in transgenic mice. Molecular and cell biological examination of early postnatal transgenic lens reveals impairment of secondary fiber cell differentiation. CONCLUSIONS: Recreation of the human lamellar cataract phenotype in mice allows investigation of this human pathology at a level not possible previously and points to the relevance of fiber cell heterogeneity dictated by fiber cell-specific gene activity in the biogenesis of the lamellar cataract.

Phenotype of transgenic mice overexpressed with inducible nitric oxide synthase in the retina.

BACKGROUND: Unlike its constitutive isoforms, including neuronal and endothelial nitric oxide synthase, inducible nitric oxide synthase (iNOS) along with a series of cytokines are generated in inflammatory pathologic conditions in retinal photoreceptors. In this study, we constructed transgenic mice overexpressing iNOS in the retina to evaluate the effect of sustained, intense iNOS generation in the photoreceptor damage. METHODS: For construction of opsin/iNOS transgene in the CMVSport 6 expression vector, the 4.4 kb Acc65I/Xhol mouse rod opsin promoter was ligated upstream to a 4.1 kb fragment encoding the complete mouse cDNA of iNOS. From the four founders identified, two heterozygote lines and one homozygote line were established. The presence of iNOS in the retina was confirmed and the pathologic role of iNOS was assessed by detecting nitrotyrosine products and apoptosis. Commercial TUNEL kit was used to detect DNA strand breaks, a later step in a sequence of morphologic changes of apoptosis process. RESULTS: The insertion and translation of iNOS gene were demonstrated by an intense single 130 kDa band in Western blot and specific immunolocalization at the photoreceptors of the retina. Cellular toxicity in the retinas of transgenic animals was detected by a post-translational modification product, tyrosine-nitrated protein, the most significant one of which was nitrated cytochrome c. Following the accumulation of nitrated mitochondrial proteins and cytochrome c release, marked apoptosis was detected in the photoreceptor cell nuclei of the retina. CONCLUSIONS: We have generated a pathologic phenotype with sustained iNOS overexpression and, therefore, high output of nitric oxide. Under basal conditions, such overexpression of iNOS causes marked mitochondrial cytochrome c nitration and release and subsequent photoreceptor apoptosis in the retina. Therefore, the modulation of pathways leading to iNOS generation or its effective neutralization can be of significant therapeutic benefit in the oxidative stress-mediated retinal degeneration, a leading cause of blindness.

Purification of BAC DNA for high-efficiency transgenesis.

An unresolved bottleneck in bacterial artificial chromosome (BAC) transgenesis is low efficiency generation of founder mice because of suboptimal quality of the manipulated BAC DNA. Using mini-gel electrophoresis and electro-elution that circumvents CsCl(2) centrifugation, column chromatography, and resin purifications, we have used RECOCHIP, a commercially available dialysis cassette for the purification of BAC DNA that generates transgenic founders with up to 80% efficiency.

Generation of human induced pluripotent stem cells bearing an anti-HIV transgene by a lentiviral vector carrying an internal murine leukemia virus promoter.

The recent development of induced pluripotent stem cells (iPSCs) by ectopic expression of defined reprogramming factors offers enormous therapeutic opportunity. To deliver these factors, murine leukemia virus (MLV)-based vectors have been broadly used in the setting of hematopoietic stem cell transplantation. However, MLV vectors have been implicated in malignancy induced by insertional mutagenesis, whereas lentiviral vectors have not. Furthermore, the infectivity of MLV vectors is limited to dividing cells, whereas lentiviral vectors can also transduce nondividing cells. One important characteristic of MLV vectors is a self-silencing property of the promoter element in pluripotent stem cells, allowing temporal transgene expression in a nonpluripotent state before iPSC derivation. Here we test iPSC generation using a novel chimeric vector carrying a mutant MLV promoter internal to a lentiviral vector backbone, thereby containing the useful properties of both types of vectors. Transgene expression of this chimeric vector was highly efficient compared with that of MLV vectors and was silenced specifically in human embryonic stem cells. Human fetal fibroblasts transduced with the vector encoding each factor were efficiently reprogrammed into a pluripotent state, and these iPSCs had potential to differentiate into a variety of cell types. To explore the possibility of iPSCs for gene therapy, we established iPSC clones expressing a short hairpin RNA (shRNA) targeting chemokine receptor 5 (CCR5), the main coreceptor for HIV-1. Using a reporter construct for CCR5 expression, we confirmed that CCR5 shRNA was expressed and specifically knocked down the reporter expression in iPSCs. These data indicate that our chimeric lentiviral vector is a valuable tool for generation of iPSCs and the combination with vectors encoding transgenes allows for rapid establishment of desired genetically engineered iPSC lines.

Live cell monitoring of hiPSC generation and differentiation using differential expression of endogenous microRNAs.

Human induced pluripotent stem cells (hiPSCs) provide new possibilities for regenerative therapies. In order for this potential to be achieved, it is critical to efficiently monitor the differentiation of these hiPSCs into specific lineages. Here, we describe a lentiviral reporter vector sensitive to specific microRNAs (miRNA) to show that a single vector bearing multiple miRNA target sequences conjugated to different reporters can be used to monitor hiPSC formation and subsequent differentiation from human fetal fibroblasts (HFFs). The reporter vector encodes EGFP conjugated to the targets of human embryonic stem cell (hESC) specific miRNAs (miR-302a and miR-302d) and mCherry conjugated to the targets of differentiated cells specific miRNAs (miR-142-3p, miR-155, and miR-223). The vector was used to track reprogramming of HFF to iPSC. HFFs co-transduced with this reporter vector and vectors encoding 4 reprogramming factors (OCT4, SOX2, KLF4 and cMYC) were mostly positive for EGFP (67%) at an early stage of hiPSC formation. EGFP expression gradually disappeared and mCherry expression increased indicating less miRNAs specific to differentiated cells and expression of miRNAs specific to hESCs. Upon differentiation of the hiPSC into embryoid bodies, a large fraction of these hiPSCs regained EGFP expression and some of those cells became single positive for EGFP. Further differentiation into neural lineages showed distinct structures demarcated by either EGFP or mCherry expression. These findings demonstrate that a miRNA dependent reporter vector can be a useful tool to monitor living cells during reprogramming of hiPSC and subsequent differentiation to lineage specific cells.