Stem cell therapy has garnered much attention and application in the past decades for the treatment of diseases and injuries. Mesenchymal stem cells (MSCs) are studied most extensively for their therapeutic roles, which appear to be derived from their paracrine activity. Recent studies suggest a critical therapeutic role for extracellular vesicles (EV) secreted by MSCs. EV are nano-sized membrane-bound vesicles that shuttle important biomolecules between cells to maintain physiological homeostasis. Studies show that EV from MSCs (MSC-EV) have regenerative and anti-inflammatory properties. The use of MSC-EV, as an alternative to MSCs, confers several advantages, such as higher safety profile, lower immunogenicity, and the ability to cross biological barriers, and avoids complications that arise from stem cell-induced ectopic tumor formation, entrapment in lung microvasculature, and immune rejection. These advantages and the growing body of evidence suggesting that MSC-EV display therapeutic roles contribute to the strong rationale for developing EV as an alternative therapeutic option. Despite the success in preclinical studies, use of MSC-EV in clinical settings will require careful consideration; specifically, several critical issues such as (i) production methods, (ii) quantification and characterization, (iii) pharmacokinetics, targeting and transfer to the target sites, and (iv) safety profile assessments need to be resolved. Keeping these issues in mind, the aim of this mini-review is to shed light on the challenges faced in MSC-EV research in translating successful preclinical studies to clinical platforms.

The ability of the human pathogenic fungus Candida albicans to switch between yeast-like and filamentous forms of growth has long been linked to pathogenesis. Numerous environmental conditions, including growth at high temperatures, nutrient limitation, and exposure to serum, can trigger this morphological switch and are frequently used in in vitro models to identify genes with roles in filamentation. Previous work has suggested that differences exist between the various in vitro models both in the genetic requirements for filamentation and transcriptional responses to distinct filamentation-inducing media, but these differences had not been analyzed in detail. We compared 10 in vitro models for filamentation and found broad genetic and transcriptomic differences between model systems. The comparative analysis enabled the discovery of novel media-independent genetic requirements for filamentation as well as a core filamentation transcriptional profile. Our data also suggest that the physical environment drives distinct programs of filamentation in C. albicans, which has significant implications for filamentation in vivo.

Oxycodone (oxy) is a semi-synthetic opioid commonly used as a pain medication that is also a widely abused prescription drug. While very limited studies have examined the effect of in utero oxy (IUO) exposure on neurodevelopment, a significant gap in knowledge is the effect of IUO compared with postnatal oxy (PNO) exposure on synaptogenesis-a key process in the formation of synapses during brain development-in the exposed offspring. One relatively unexplored form of cell-cell communication associated with brain development in response to IUO and PNO exposure are extracellular vesicles (EVs). EVs are membrane-bound vesicles that serve as carriers of cargo, such as microRNAs (miRNAs). Using RNA-Seq analysis, we identified distinct brain-derived extracellular vesicle (BDEs) miRNA signatures associated with IUO and PNO exposure, including their gene targets, regulating key functional pathways associated with brain development to be more impacted in the IUO offspring. Further treatment of primary 14-day in vitro (DIV) neurons with IUO BDEs caused a significant reduction in spine density compared to treatment with BDEs from PNO and saline groups. In summary, our studies identified for the first time, key BDE miRNA signatures in IUO-and PNO-exposed offspring, which could impact their brain development as well as synaptic function.Cells 2020, 9, 21 2 of 18 lack of studies that have compared the effect of in utero oxy (IUO) and postnatal oxy (PNO) exposure on synaptogenesis-a key process of the formation of synapses during brain development-in the exposed offspring. Synapses are key communication points between neurons, which play a critical role in the regulation of neurotransmission and brain plasticity [6].One relatively unexplored form of cell-cell communication associated with brain development in response to IUO and PNO exposure is extracellular vesicles (EVs) [7][8][9]. These membrane-bound vesicles, comprised of exosomes and microvesicles, originate from the multivesicular bodies and plasma membrane, respectively. Furthermore, these EVs, which carry a repertoire of cargo, including microRNAs (miRNAs), are shown to induce inflammation and subsequent neuronal damage, thus serving as key mediators of pathogenesis in several neurological and neurodegenerative disorders [10,11]. The main objective of this study was to identify differentially expressed BDEs miRNAs using RNA sequencing (RNA-Seq) and evaluate their impact on synaptic architecture during a key stage of brain development.

Prescription opioid abuse during and after pregnancy is a rising public health concern. While earlier studies have documented that offspring exposed to opioids in utero have impaired neurodevelopment, a significant knowledge gap remains in comparing the overall development between offspring exposed in utero and postnatally. Adding a layer of complexity is the role of heredity in the overall development of these exposed offspring. To fill in these important knowledge gaps, the current study uses a preclinical rat model mimicking oxycodone (oxy) exposure in utero (IUO) and postnatally (PNO) to investigate comparative and intergenerational effects in the two different treatment groups. While significant phenotypic attributes were observed with the two treatments and across the two generations, RNA sequencing revealed alterations in the expression of key synaptic genes in the two exposed groups in both generations. RNA sequencing and post validation of genes using RT-PCR highlighted the differential expression of several neuropeptides associated with the hypocretin system, a system recently implicated in addiction. Further, behavior studies revealed anxiety-like behaviors and social deficits that persisted even in the subsequent generations in the two treatment groups. To summarize, our study for the first time reveals a new line of investigation on the potential risks associated with oxy use during and after pregnancy, specifically the disruption of neurodevelopment and intergenerational impact on behavior.

Extracellular vesicles (EVs), which express a repertoire of cargo molecules (cf. proteins, microRNA, lipids, etc.), have been garnering a prominent role in the modulation of several cellular processes. Here, using both non‐human primate and rodent model systems, we provide evidence that brain‐derived EV (BDE) miRNA, miR‐29a‐3p (mir‐29a), is significantly increased during chronic methamphetamine (MA) exposure. Further, miR‐29a levels show significant increase both with drug‐seeking and reinstatement in a rat MA self‐administration model. We also show that EV‐associated miR‐29a is enriched in EV pool comprising of small EVs and exomeres and further plays a critical role in MA‐induced inflammation and synaptodendritic damage. Furthermore, treatment with the anti‐inflammatory drug ibudilast (AV411), which is known to reduce MA relapse, decreased the expression of miR‐29a and subsequently attenuated inflammation and rescued synaptodendritic injury. Finally, using plasma from MUD subjects, we provide translational evidence that EV‐miR29a could potentially serve as a biomarker to detect neuronal damage in humans diagnosed with MA use disorder (MUD). In summary, our work suggests that EV‐associated miR‐29a‐3p plays a crucial role in MUD and might be used as a potential blood‐based biomarker for detecting chronic inflammation and synaptic damage.