Determinants of effective lentivirus-driven microRNA expression in vivo

Regulation and therapeutic potentials of microRNAs to non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 80%-85% of total cases and leading to millions of deaths worldwide. Drug resistance is the primary cause of treatment failure in NSCLC, which urges scientists to develop advanced approaches for NSCLC treatment. Among novel approaches, the miRNA-based method has emerged as a potential approach as it allows researchers to modulate target gene expression. Subsequently, cell behaviors are altered, which leads to the death and the depletion of cancer cells. It has been reported that miRNAs possess the capacity to regulate multiple genes that are involved in various signaling pathways, including the phosphoinositide 3-kinase, receptor tyrosine kinase/rat sarcoma virus/mitogen-activated protein kinase, wingless/integrated, retinoblastoma, p53, transforming growth factor β, and nuclear factor-kappa B pathways. Dysregulation of these signaling pathways in NSCLC results in abnormal cell proliferation, tissue invasion, and drug resistance while inhibiting apoptosis. Thus, understanding the roles of miRNAs in regulating these signaling pathways may enable the development of novel NSCLC treatment therapies. However, a comprehensive review of potential miRNAs in NSCLC treatment has been lacking. Therefore, this review aims to fill the gap by summarizing the up-to-date information on miRNAs regarding their targets, impact on cancer-associated pathways, and prospective outcomes in treating NSCLC. We also discuss current technologies for delivering miRNAs to the target cells, including virus-based, non-viral, and emerging extracellular vesicle-based delivery systems. This knowledge will support future studies to develop an innovative miRNA-based therapy and select a suitable carrier to treat NSCLC effectively.

The lipase cofactor CGI58 controls placental lipolysis

In eutherians, the placenta plays a critical role in the uptake, storage, and metabolism of lipids. These processes govern the availability of fatty acids to the developing fetus, where inadequate supply has been associated with substandard fetal growth. Whereas lipid droplets are essential for the storage of neutral lipids in the placenta and many other tissues, the processes that regulate placental lipid droplet lipolysis remain largely unknown. To assess the role of triglyceride lipases and their cofactors in determining placental lipid droplet and lipid accumulation, we assessed the role of patatin like phospholipase domain containing 2 (PNPLA2) and comparative gene identification-58 (CGI58) in lipid droplet dynamics in the human and mouse placenta. While both proteins are expressed in the placenta, the absence of CGI58, not PNPLA2, markedly increased placental lipid and lipid droplet accumulation. These changes were reversed upon restoration of CGI58 levels selectively in the CGI58-deficient mouse placenta. Using co-immunoprecipitation, we found that, in addition to PNPLA2, PNPLA9 interacts with CGI58. PNPLA9 was dispensable for lipolysis in the mouse placenta yet contributed to lipolysis in human placental trophoblasts. Our findings establish a crucial role for CGI58 in placental lipid droplet dynamics and, by extension, in nutrient supply to the developing fetus.

microRNA-96 targets the INS/AKT/GLUT4 signaling axis: Association with and effect on diabetic retinopathy

Background

miR-96-5p is a highly expressed microRNA in the retina of subjects with diabetes. The INS/AKT/GLUT4 signaling axis is the main cell signaling pathway of glucose uptake in cells. Here, we investigated the role of miR-96-5p in this signaling pathway.

Methods

Expression levels of miR-96-5p and its target genes were measured under high glucose conditions, in the retina of streptozotocin-induced diabetic mice, in the retina of AAV-2-eGFP-miR-96 or GFP intravitreal injected mice and in the retina of human donors with diabetic retinopathy (DR). MTT, wound healing, tube formation, Western blot, TUNEL, angiogenesis assays and hematoxylin-eosin staining of the retinal sections were performed.

Results

miR-96-5p expression was increased under high glucose conditions in mouse retinal pigment epithelial (mRPE) cells, in the retina of mice receiving AAV-2 carrying miR-96 and STZ-treated mice. Expression of the miR-96-5p target genes related to the INS/AKT/GLUT4 signaling pathway was reduced following miR-96-5p overexpression. mmu-miR-96-5p expression decreased cell proliferation and thicknesses of retinal layers. Cell migration, tube formation, vascular length, angiogenesis, and TUNEL-positive cells were increased.

Conclusions

In in vitro and in vivo studies and in human retinal tissues, miR-96-5p regulated the expression of the PIK3R1, PRKCE, AKT1, AKT2, and AKT3 genes in the INS/AKT axis and some genes involved in GLUT4 trafficking, such as Pak1, Snap23, RAB2a, and Ehd1. Because disruption of the INS/AKT/GLUT4 signaling axis causes advanced glycation end product accumulation and inflammatory responses, the inhibition of miR-96-5p expression could ameliorate DR.

Potential involvement of miR-183/96/182 cluster-gene target interactions in transdifferentiation of human retinal pigment epithelial cells into retinal neurons

miR-183/96/182 cluster plays a critical role in the developing retina by regulating many target genes involved in signaling pathways. This study aimed to survey the miR-183/96/182 cluster-target interactions that, potentially contribute to human retinal pigmented epithelial (hRPE) cell differentiation into photoreceptors. Target genes of the miR-183/96/182 cluster were obtained from miRNA-target databases and applied to construct miRNA-target networks. Gene ontology and KEGG pathway analysis was performed. miR-183/96/182 cluster sequence was cloned into an eGFP-intron splicing cassette in an AAV2 vector and overexpressed in hRPE cells. The expression level of target genes including HES1, PAX6, SOX2, CCNJ, and RORΒ was evaluated using qPCR. Our results showed that miR-183, miR-96, and miR-182 share 136 target genes that are involved in cell proliferation pathways such as PI3K/AKT and MAPK pathway. qPCR data indicated a 22-, 7-, and 4-fold overexpression of miR-183, miR-96, and miR-182, respectively, in infected hRPE cells. Consequently, the downregulation of several key targets such as PAX6, CCND2, CDK5R1, and CCNJ and upregulation of a few retina-specific neural markers such as Rhodopsin, red opsin, and CRX was detected. Our findings suggest that the miR-183/96/182 cluster may induce hRPE transdifferentiation by targeting key genes that involve in the cell cycle and proliferation pathways.

Human MicroRNAs Attenuate the Expression of Immediate Early Proteins and HCMV Replication during Lytic and Latent Infection in Connection with Enhancement of Phosphorylated RelA/p65 (Serine 536) That Binds to MIEP

Attenuating the expression of immediate early (IE) proteins is essential for controlling the lytic replication of human cytomegalovirus (HCMV). The human microRNAs (hsa-miRs), miR-200b-3p and miR-200c-3p, have been identified to bind the 3′-untranslated region (3′-UTR) of the mRNA encoding IE proteins. However, whether hsa-miRs can reduce IE72 expression and HCMV viral load or exhibit a crosstalk with the host cellular signaling machinery, most importantly the NF-κB cascade, has not been evaluated. In this study, argonaute-crosslinking and immunoprecipitation-seq revealed that miR-200b-3p and miR-200c-3p bind the 3′-UTR of UL123, which is a gene that encodes IE72. The binding of these miRNAs to the 3′-UTR of UL123 was verified in transfected cells stably expressing GFP. We used miR-200b-3p/miR-200c-3p mimics to counteract the downregulation of these miRNA after acute HCMV infection. This resulted in reduced IE72/IE86 expression and HCMV VL during lytic infection. We determined that IE72/IE86 alone can inhibit the phosphorylation of RelA/p65 at the Ser⁵³⁶ residue and that p-Ser⁵³⁶ RelA/p65 binds to the major IE promoter/enhancer (MIEP). The upregulation of miR-200b-3p and miR-200c-3p resulted in the phosphorylation of RelA/p65 at Ser⁵³⁶ through the downregulation of IE, and the binding of the resultant p-Ser⁵³⁶ RelA/p65 to MIEP resulted in a decreased production of pro-inflammatory cytokines. Overall, miR-200b-3p and miR-200c-3p—together with p-Ser⁵³⁶ RelA/p65—can prevent lytic HCMV replication during acute and latent infection

Optimization of miR-22 expression cassette for rAAV delivery on diabetes

MicroRNA-22 (miR-22) was suggested to be important for type 2 diabetes but its functions for this disease remained unclear. Recombinant adeno-associated virus (rAAV)-mediated miR delivery is a powerful approach to study miR functions in vivo, however, the overexpression of miR-22 by rAAV remains challenging because it is one of the most abundant miRs in the liver. In this study, a series of expression cassettes were designed and compared. It was shown that different lengths of primary miR-22 were overexpressed in HEK293 and HeLa cells but the longer ones were more efficiently expressed. miR-22 may be placed in either introns or the 3′ UTR of a transgene for efficient overexpression. RNA polymerase III or II promoters were successfully utilized for miR expression but the latter showed higher expression levels in cell lines. Specifically, miR-22 was expressed efficiently together with an EGFP gene. After screening, a liver-specific TTR promoter was chosen to overexpress miR-22 in diabetic mice fed a high-fat diet. It was shown that miR-22 was overexpressed 2-3 folds which improved the insulin sensitivity significantly. The approach utilized in this study to optimize miR overexpression is a powerful tool for the creation of efficient rAAV vectors for the other miRs.

Mir-106b Cluster Regulates Primordial Germ Cells Differentiation from Human Mesenchymal Stem Cells

Objective

Numerous evidence indicates that microRNAs (miRNAs) are critical regulators in the spermatogenesis process. The aim of this study was to investigate Mir-106b cluster regulates primordial germ cells (PGCs) differentiation from human mesenchymal stem cells (MSCs).

Materials and Methods

In this experimental study, samples containing male adipose (n: 9 samples- age: 25-40 years) were obtained from cosmetic surgeries performed for the liposuction in Imam Khomeini Hospital. The differentiation of MSCs into PGCs was accomplished by transfection of a lentivector expressing miR-106b. The transfection of miR- 106b was also confirmed by the detection of a clear green fluorescent protein (GFP) signal in MSCs. MSCs were treated with bone morphogenic factor 4 (BMP4) protein, as a putative inducer of PGCs differentiation, to induce the differentiation of MSCs into PGCs (positive control). After 4 days of transfection, the expression of miR-106b, STELLA, and FRAGILIS genes was evaluated by real-time polymerase chain reaction (PCR). Also, the levels of thymocyte differentiation antigen 1 (Thy1) protein was assessed by the western blot analysis. The cell surface expression of CD90 was also determined by immunocytochemistry method. The cytotoxicity of miR-106b was examined in MSCs after 24, 48, and 72 hours using the MTT assay.

Results

MSCs treated with BMP4 or transfected by miR-106b were successfully differentiated into PGCs. The results of this study also showed that the expression of miR-106b was significantly increased after 48 hours from transfection. Also, we showed STELLA, FARGILIS, as well as the protein expression of Thy1, was significantly higher in MSCs transfected by lentivector expressing miR-106b in comparison with MSCs treated with BMP4 (P≤0.05). MTT assay showed miR-106b was no toxic during 72 hours in 1 µg/ml dose, that this amount could elevated germ cells marker significantly higher than other experimental groups (P≤0.05).

Conclusion

According to this findings, it appears that miR-106b plays an essential role in the differentiation of MSCs into PGCs.

Placental response to maternal SARS-CoV-2 infection

The coronavirus disease 2019 (COVID-19) pandemic affected people at all ages. Whereas pregnant women seemed to have a worse course of disease than age-matched non-pregnant women, the risk of feto-placental infection is low. Using a cohort of 66 COVID-19-positive women in late pregnancy, we correlated clinical parameters with disease severity, placental histopathology, and the expression of viral entry and Interferon-induced transmembrane (IFITM) antiviral transcripts. All newborns were negative for SARS-CoV-2. None of the demographic parameters or placental histopathological characteristics were associated with disease severity. The fetal-maternal transfer ratio for IgG against the N or S viral proteins was commonly less than one, as recently reported. We found that the expression level of placental ACE2, but not TMPRSS2 or Furin, was higher in women with severe COVID-19. Placental expression of IFITM1 and IFITM3, which have been implicated in antiviral response, was higher in participants with severe disease. We also showed that IFITM3 protein expression, which localized to early and late endosomes, was enhanced in severe COVID-19. Our data suggest an association between disease severity and placental SARS-CoV-2 processing and antiviral pathways, implying a role for these proteins in placental response to SARS-CoV-2.

Current State of Preeclampsia Mouse Models: Approaches, Relevance, and Standardization

Preeclampsia (PE) is a multisystemic, pregnancy-specific disorder and a leading cause of maternal and fetal death. PE is also associated with an increased risk for chronic morbidities later in life for mother and offspring. Abnormal placentation or placental function has been well-established as central to the genesis of PE; yet much remains to be determined about the factors involved in the development of this condition. Despite decades of investigation and many clinical trials, the only definitive treatment is parturition. To better understand the condition and identify potential targets preclinically, many approaches to simulate PE in mice have been developed and include mixed mouse strain crosses, genetic overexpression and knockout, exogenous agent administration, surgical manipulation, systemic adenoviral infection, and trophoblast-specific gene transfer. These models have been useful to investigate how biological perturbations identified in human PE are involved in the generation of PE-like symptoms and have improved the understanding of the molecular mechanisms underpinning the human condition. However, these approaches were characterized by a wide variety of physiological endpoints, which can make it difficult to compare effects across models and many of these approaches have aspects that lack physiological relevance to this human disorder and may interfere with therapeutic development. This report provides a comprehensive review of mouse models that exhibit PE-like symptoms and a proposed standardization of physiological characteristics for analysis in murine models of PE.

Intraneural Application of microRNA-1 Mimetic Nucleotides Does Not Resolve Neuropathic Pain After Chronic Constriction Injury in Rats

Background

Alterations of the expression of microRNAs (miRNAs) in chronic pain models seem to play a crucial role in the development of neuropathic pain, with microRNA-1 (miR-1) being of particular interest. Recently, we were able to show that decreased miR-1 levels were associated with increased expression of brain-derived neurotrophic factor (BDNF) and Connexin 43 (Cx43). We hypothesized that miR-1 mimetic nucleotides could alleviate neuropathic pain caused by chronic constriction injury in rats.

Methods

MiR-1 mimetic nucleotides were evaluated for effectiveness, functionality, and intracellular stability by transfecting human glioblastoma cells (U-87 MG). In vivo transfection with miR-1 mimics and corresponding scrambled miRNAs serving as control was performed by repetitive injection (days 0, 3, and 7) into the sciatic nerve following chronic constriction injury (CCI) in rats. Quantitative PCR was used to measure miR-1 content. Cx43 expression was determined by Western blot analysis. Effects on neuropathic pain were assessed by detecting paw withdrawal thresholds using an automated filament application.

Results

Transfection of miR-1 mimics was confirmed in U-87 MG cells, with miR-1 content being increased significantly after 48 h and after 96 h (p<0.05). Effective downregulation of Cx43 expression was observed 48 and 96 h after transfection (−44 ± 0.07% and −40 ± 0.11%; p<0.05). In vivo, repetitive transfection with miR-1 mimetic nucleotides led to a 17.9-fold (± 14.2) increase of miR-1 in the sciatic nerve. However, the protein expression of Cx43 in sciatic nerves as well as paw withdrawal thresholds for mechanical stimulation was not significantly increased 10 days after chronic constriction injury.

Conclusion

While transfection with miR-1 mimics effective reduces Cx43 expression in vitro and restores miR-1 after CCI, we did neither observe altered levels of Cx43 protein level in nerves nor a beneficial effect on mechanical allodynia in vivo, most likely caused by insufficient Cx43 suppression.

Ultrasound-Mediated Gene Therapy of Hepatocellular Carcinoma Using Pre-microRNA Plasmid-Loaded Nanodroplets

The PIK3 CA gene encodes the p110α protein subunit and is one of the most efficient cancer genes in solid and hematological tumors including hepatocellular carcinoma (HCC). There are currently ongoing therapies against tumors based on PIK3 CA inhibition. Because microRNAs (miRNAs) play an important role in post-transcriptional regulation and are also involved in the inhibition of PIK3 CA expression to suppress cancer cell proliferation, overexpression of tumor-suppressive miRNA is a promising therapeutic approach for HCC therapy. The successful and localized delivery of miRNA overexpression vectors (pre-miRNA plasmids) is very important in improving the therapeutic efficacy of this miRNA therapy strategy. In the study described here, submicron acoustic phase-shifted nanodroplets were used to efficiently deliver pre-miRNA plasmid in vitro and in vivo for HCC therapy under focused ultrasound (US) activation. Briefly, six miRNAs, inhibiting PIK3 CA and downregulated in HCC, were selected through summary and analysis of the currently existing literature data. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and cell apoptosis assay revealed that pre-miR-139, -203a, -378a and -422a plasmids among the six miRNA overexpression vectors could suppress growth of the hepatoma cell line SMMC-7721. These four pre-miRNA plasmids were then electrostatically adhered to positively charged lipid-shelled nanodroplets to obtain plasmid-loaded nanodroplets (PLNDs). The PLND-generated microbubbles oscillated and even collapsed under US exposure to release the loaded pre-miRNA plasmids and enhance their cellular uptake through consequent sonoporation, that is, formation of small pores on the cell membrane induced by the mechanical effects of PLND cavitation. Fluorescence microscopy results revealed that PLNDs could effectively deliver the aforementioned four pre-miRNA plasmids into SMMC-7721 cells in vitro under 1.2-MHz 60-cycle sinusoid US exposure with a peak negative pressure >5.5 MPa at a 40-Hz pulse repetition frequency. Plasmid delivery efficiency and cell viability positively correlated with the inertial cavitation dose that was determined mainly by peak negative pressure. Furthermore, PLNDs combined with US were evaluated in vivo to deliver these four pre-miRNAs plasmids and verify their therapeutic efficacy in subcutaneous tumor of the mouse xenograft HCC model. The results revealed that the PLNDs loaded with pre-miR-139 and -378a plasmids could effectively suppress tumor growth after US treatment. Thus, combination of pre-miRNA PLNDs with US activation seems to constitute a potential strategy for HCC therapy.

hsa-let-7c miRNA Regulates Synaptic and Neuronal Function in Human Neurons

Non-coding RNA, including microRNA (miRNA) serves critical regulatory functions in the developing brain. The let-7 family of miRNAs has been shown to regulate neuronal differentiation, neural subtype specification, and synapse formation in animal models. However, the regulatory role of human let-7c (hsa-let-7c) in human neuronal development has yet to be examined. Let-7c is encoded on chromosome 21 in humans and therefore may be overexpressed in human brains in Trisomy 21 (T21), a complex neurodevelopmental disorder. Here, we employ recent developments in stem cell biology to show that hsa-let-7c mediates important regulatory epigenetic functions that control the development and functional activity of human induced neuronal cells (iNs). We show that overexpression of hsa-let-7c in human iNs derived from induced pluripotent stem (iPS), as well as embryonic stem (ES), cells leads to morphological as well as functional deficits including impaired neuronal morphologic development, synapse formation and synaptic strength, as well as a marked reduction of neuronal excitability. Importantly, we have assessed these findings over three independent genetic backgrounds, showing that some of these effects are subject to influence by background genetic variability with the most robust and reproducible effect being a striking reduction in spontaneous neural firing. Collectively, these results suggest an important function for let-7 family miRNAs in regulation of human neuronal development and raise implications for understanding the complex molecular etiology of neurodevelopmental disorders, such as T21, where let-7c gene dosage is increased.

microRNAs in skeletal muscle development

A fundamental process during both embryo development and stem cell differentiation is the control of cell lineage determination. In developing skeletal muscle, many of the diffusible signaling molecules, transcription factors and more recently non-coding RNAs that contribute to this process have been identified. This has facilitated advances in our understanding of the molecular mechanisms underlying the control of cell fate choice. Here we will review the role of non-coding RNAs, in particular microRNAs (miRNAs), in embryonic muscle development and differentiation, and in satellite cells of adult muscle, which are essential for muscle growth and regeneration. Some of these short post-transcriptional regulators of gene expression are restricted to skeletal muscle, but their expression can also be more widespread. In addition, we discuss a few examples of long non-coding RNAs, which are numerous but much less well understood.

Placenta-specific gene manipulation using lentiviral vector and its application

The placenta is an essential organ for embryo development in the uterus of eutherian mammals. Large contributions in unveiling molecular mechanisms and physiological functions underlying placental formation were made by analyzing mutant and transgenic animals. However, it had been difficult to elucidate whether the placental defects observed in such animals originate from the placenta itself or from the fetus, as both placental and fetal genomes are modified. Therefore strategies to modify the placental genome without affecting the "fetal genome" had been needed. Through the ingenious use of lentiviral (LV) vectors, placenta-specific modification is now possible. Lentivirus is a genus of retroviruses that use reverse-transcriptase to convert its single-strand RNA genome to double-strand DNA and integrate into the host genome. Previous studies showed that when LV vectors were used to transduce embryos at the 2-cell stage, the viral genome is systemically introduced into host genome. Interestingly, by delaying the timing of transduction to the blastocyst stage, the transgene is expressed specifically in the placenta as a consequence of trophectoderm-specific viral transduction. This review summarizes the development of the LV vector-mediated placenta-specific gene manipulation technology and its application in placental research over the past decade. A perspective for future application of LV vectors to further placenta research, especially in combination with next generation genome editing technologies, is also presented.

Expression and trafficking of placental microRNAs at the feto-maternal interface

During pregnancy, placental trophoblasts at the feto-maternal interface produce a broad repertoire of microRNA (miRNA) species. These species include miRNA from the primate-specific chromosome 19 miRNA cluster (C19MC), which is expressed nearly exclusively in the placenta. Trafficking of these miRNAs among the maternal, placental, and fetal compartments is unknown. To determine miRNA expression and trafficking patterns during pregnancy, we sequenced miRNAs in triads of human placenta and of maternal and fetal blood and found large subject-to-subject variability, with C19MC exhibiting compartment-specific expression. We therefore created humanized mice that transgenically express the entire 160-kb human C19MC locus or lentivirally express C19MC miRNA members selectively in the placenta. C19MC transgenic mice expressed a low level of C19MC miRNAs in diverse organs. When pregnant, female C19MC mice exhibited a strikingly elevated (>40-fold) expression of C19MC miRNA in the placenta, compared with other organs, that resembled C19MC miRNAs patterns in humans. Our mouse models showed that placental miRNA traffic primarily to the maternal circulation and that maternal miRNA can traffic to the placenta and even into the fetal compartment. These findings define an extraordinary means of nonhormonal, miRNA-based communication between the placenta and feto-maternal compartments.-Chang, G., Mouillet, J.-F., Mishima, T., Chu, T., Sadovsky, E., Coyne, C. B., Parks, W. T., Surti, U., Sadovsky, Y. Expression and trafficking of placental microRNAs at the feto-maternal interface.