Combinatorial programming of human neuronal progenitors using magnetically-guided stoichiometric mRNA delivery

Therapeutic applications of cell engineering using mRNA technology

Engineering and reprogramming cells has significant therapeutic potential to treat a wide range of diseases, by replacing missing or defective proteins, to provide transcription factors (TFs) to reprogram cell phenotypes, or to provide enzymes such as RNA-guided Cas9 derivatives for CRISPR-based cell engineering. While viral vector-mediated gene transfer has played an important role in this field, the use of mRNA avoids safety concerns associated with the integration of DNA into the host cell genome, making mRNA particularly attractive for in vivo applications. Widespread application of mRNA for cell engineering is limited by its instability in the biological environment and challenges involved in the delivery of mRNA to its target site. In this review, we examine challenges that must be overcome to develop effective therapeutics.

Advances in neuronal reprogramming for neurodegenerative diseases: Strategies, controversies, and opportunities

Neuronal death is often observed in central nervous system injuries and neurodegenerative diseases. The mammalian central nervous system manifests limited neuronal regeneration capabilities, and traditional cell therapies are limited in their potential applications due to finite cell sources and immune rejection. Neuronal reprogramming has emerged as a novel technology, in which non-neuronal cells (e.g. glial cells) are transdifferentiated into mature neurons. This process results in relatively minimal immune rejection. The present review discuss the latest progress in this cutting-edge field, including starter cell selection, innovative technical strategies and methods of neuronal reprogramming for neurodegenerative diseases, as well as the potential problems and controversies. The further development of neuronal reprogramming technology may pave the way for novel therapeutic strategies in the treatment of neurodegenerative diseases.

The Crucial Roles of Pitx3 in Midbrain Dopaminergic Neuron Development and Parkinson's Disease-Associated Neurodegeneration

The degeneration of midbrain dopaminergic (mDA) neurons, particularly in the substantia nigra pars compacta (SNc), is one of the most prominent pathological hallmarks of Parkinson's disease (PD). To uncover the pathogenic mechanisms of mDA neuronal death during PD may provide therapeutic targets to prevent mDA neuronal loss and slow down the disease's progression. Paired-like homeodomain transcription factor 3 (Pitx3) is selectively expressed in the mDA neurons as early as embryonic day 11.5 and plays a critical role in mDA neuron terminal differentiation and subset specification. Moreover, Pitx3-deficient mice exhibit some canonical PD-related features, including the profound loss of SNc mDA neurons, a dramatic decrease in striatal dopamine (DA) levels, and motor abnormalities. However, the precise role of Pitx3 in progressive PD and how this gene contributes to mDA neuronal specification during early stages remains unclear. In this review, we updated the latest findings on Pitx3 by summarizing the crosstalk between Pitx3 and its associated transcription factors in mDA neuron development. We further explored the potential benefits of Pitx3 as a therapeutic target for PD in the future. To better understand the transcriptional network of Pitx3 in mDA neuron development may provide insights into Pitx3-related clinical drug-targeting research and therapeutic approaches.

Diseased, differentiated and difficult: Strategies for improved engineering of in vitro neurological systems

The rapidly growing field of cellular engineering is enabling scientists to more effectively create in vitro models of disease and develop specific cell types that can be used to repair damaged tissue. In particular, the engineering of neurons and other components of the nervous system is at the forefront of this field. The methods used to engineer neural cells can be largely divided into systems that undergo directed differentiation through exogenous stimulation (i.e., via small molecules, arguably following developmental pathways) and those that undergo induced differentiation via protein overexpression (i.e., genetically induced and activated; arguably bypassing developmental pathways). Here, we highlight the differences between directed differentiation and induced differentiation strategies, how they can complement one another to generate specific cell phenotypes, and impacts of each strategy on downstream applications. Continued research in this nascent field will lead to the development of improved models of neurological circuits and novel treatments for those living with neurological injury and disease.

Gut microbiota and inflammatory bowel disease

Gut microbiota refers to the complex aggregation of microbes in gut, including bacteria, archaea, fungi, and viruses, and they exert marked influence on the host's health. Perturbations in the gut microbiota have been closely linked to initiation and progression of IBD, which has become a disease with accelerating incidence worldwide, but it remains to be thoroughly investigated how microbial involvement might contribute to IBD. In this review, we discuss the current research findings concerning alterations in the gut microbiota, trans-kingdom interaction between the members of the gut microbiota, their interactions with the immune system of host, their potential role in the IBD pathogenesis, and the relationship between gut microbiota and IBD. We hope to provide a better understanding of the causes of IBD and shed light on the development of microbiome-based therapeutic approaches, which might be a promising strategy to alleviate, manage, and eventually cure IBD. This article is categorized under: Infectious Diseases > Genetics/Genomics/Epigenetics Infectious Diseases > Molecular and Cellular Physiology.

Roles of Transcription Factors in the Development and Reprogramming of the Dopaminergic Neurons

The meso-diencephalic dopaminergic (mdDA) neurons regulate various critical processes in the mammalian nervous system, including voluntary movement and a wide range of behaviors such as mood, reward, addiction, and stress. mdDA neuronal loss is linked with one of the most prominent human movement neurological disorders, Parkinson’s disease (PD). How these cells die and regenerate are two of the most hotly debated PD research topics. As for the latter, it has been long known that a series of transcription factors (TFs) involves the development of mdDA neurons, specifying cell types and controlling developmental patterns. In vitro and in vivo, TFs regulate the expression of tyrosine hydroxylase, a dopamine transporter, vesicular monoamine transporter 2, and L-aromatic amino acid decarboxylase, all of which are critical for dopamine synthesis and transport in dopaminergic neurons (DA neurons). In this review, we encapsulate the molecular mechanism of TFs underlying embryonic growth and maturation of mdDA neurons and update achievements on dopaminergic cell therapy dependent on knowledge of TFs in mdDA neuronal development. We believe that a deeper understanding of the extrinsic and intrinsic factors that influence DA neurons’ fate and development in the midbrain could lead to a better strategy for PD cell therapy.

Synthetic mRNA nanoparticle-mediated restoration of p53 tumor suppressor sensitizes p53-deficient cancers to mTOR inhibition

Loss of function in tumor suppressor genes is commonly associated with the onset/progression of cancer and treatment resistance. The p53 tumor suppressor gene, a master regulator of diverse cellular pathways, is frequently altered in various cancers, for example, in ~36% of hepatocellular carcinomas (HCCs) and ~68% of non-small cell lung cancers (NSCLCs). Current methods for restoration of p53 expression, including small molecules and DNA therapies, have yielded progressive success, but each has formidable drawbacks. Here, a redox-responsive nanoparticle (NP) platform is engineered for effective delivery of p53-encoding synthetic messenger RNA (mRNA). We demonstrate that the synthetic p53-mRNA NPs markedly delay the growth of p53-null HCC and NSCLC cells by inducing cell cycle arrest and apoptosis. We also reveal that p53 restoration markedly improves the sensitivity of these tumor cells to everolimus, a mammalian target of rapamycin (mTOR) inhibitor that failed to show clinical benefits in advanced HCC and NSCLC. Moreover, cotargeting of tumor-suppressing p53 and tumorigenic mTOR signaling pathways results in marked antitumor effects in vitro and in multiple animal models of HCC and NSCLC. Our findings indicate that restoration of tumor suppressors by the synthetic mRNA NP delivery strategy could be combined together with other therapies for potent combinatorial cancer treatment.

Transcription Factor-Based Fate Specification and Forward Programming for Neural Regeneration

Traditionally, in vitro generation of donor cells for brain repair has been dominated by the application of extrinsic growth factors and morphogens. Recent advances in cell engineering strategies such as reprogramming of somatic cells into induced pluripotent stem cells and direct cell fate conversion have impressively demonstrated the feasibility to manipulate cell identities by the overexpression of cell fate-determining transcription factors. These strategies are now increasingly implemented for transcription factor-guided differentiation of neural precursors and forward programming of pluripotent stem cells toward specific neural subtypes. This review covers major achievements, pros and cons, as well as future prospects of transcription factor-based cell fate specification and the applicability of these approaches for the generation of donor cells for brain repair.