Cellular specialization is particularly prominent in mammalian nervous systems, which are composed of millions to billions of neurons that appear in thousands of different 'flavors' and contribute to ...a variety of functions. Even in a single brain region, individual neurons differ greatly in their morphology, connectivity and electrophysiological properties. Systematic classification of all mammalian neurons is a key goal towards deconstructing the nervous system into its basic components. With the recent advances in single-cell gene expression profiling technologies, it is now possible to undertake the enormous task of disentangling neuronal heterogeneity. High-throughput single-cell RNA sequencing and multiplexed quantitative RT-PCR have become more accessible, and these technologies enable systematic categorization of individual neurons into groups with similar molecular properties. Here we provide a conceptual and practical guide to classification of neural cell types using single-cell gene expression profiling technologies.
Glaucoma is a common cause of vision loss or blindness and reduction of intraocular pressure (IOP) has been proven beneficial in a large fraction of glaucoma patients. The IOP is maintained by the ...trabecular meshwork (TM) and the elevation of IOP in open-angle glaucoma is associated with dysfunction and loss of the postmitotic cells residing within this tissue. To determine if IOP control can be maintained by replacing lost TM cells, we transplanted TM-like cells derived from induced pluripotent stem cells into the anterior chamber of a transgenic mouse model of glaucoma. Transplantation led to significantly reduced IOP and improved aqueous humor outflow facility, which was sustained for at least 9 wk. The ability to maintain normal IOP engendered survival of retinal ganglion cells, whose loss is ultimately the cause for reduced vision in glaucoma. In vivo and in vitro analyses demonstrated higher TM cellularity in treated mice compared with littermate controls and indicated that this increase is primarily because of a proliferative response of endogenous TM cells. Thus, our study provides in vivo demonstration that regeneration of the glaucomatous TM is possible and points toward novel approaches in the treatment of this disease.
Sibling rivalry in the E2F family Lees, Jacqueline A; Trimarchi, Jeffrey M
Nature reviews. Molecular cell biology,
200201, 2002-Jan, 2002-1-00, 20020101, Letnik:
3, Številka:
1
Journal Article
Recenzirano
The E2F transcription factor family determines whether or not a cell will divide by controlling the expression of key cell-cycle regulators. The individual E2Fs can be divided into distinct subgroups ...that act in direct opposition to one another to promote either cellular proliferation or cell-cycle exit and terminal differentiation. What is the underlying molecular basis of this 'push-me-pull-you' regulation, and what are its biological consequences?
The development of complex tissues requires that mitotic progenitor cells integrate information from the environment. The highly varied outcomes of such integration processes undoubtedly depend at ...least in part upon variations among the gene expression programs of individual progenitor cells. To date, there has not been a comprehensive examination of these differences among progenitor cells of a particular tissue. Here, we used comprehensive gene expression profiling to define these differences among individual progenitor cells of the vertebrate retina. Retinal progenitor cells (RPCs) have been shown by lineage analysis to be multipotent throughout development and to produce distinct types of daughter cells in a temporal, conserved order. A total of 42 single RPCs were profiled on Affymetrix arrays. In situ hybridizations performed on both retinal sections and dissociated retinal cells were used to validate the results of the microarrays. An extensive amount of heterogeneity in gene expression among RPCs, even among cells isolated from the same developmental time point, was observed. While many classes of genes displayed heterogeneity of gene expression, the expression of transcription factors constituted a significant amount of the observed heterogeneity. In contrast to previous findings, individual RPCs were found to express multiple bHLH transcription factors, suggesting alternative models to those previously developed concerning how these factors may be coordinated. Additionally, the expression of cell cycle related transcripts showed differences among those associated with G2 and M, versus G1 and S phase, suggesting different levels of regulation for these genes. These data provide insights into the types of processes and genes that are fundamental to cell fate choices, proliferation decisions, and, for cells of the central nervous system, the underpinnings of the formation of complex circuitry.
Previous lineage analyses have shown that retinal progenitor cells (RPCs) are multipotent throughout development, and expression-profiling studies have shown a great deal of molecular heterogeneity ...among RPCs. To determine if the molecular heterogeneity predicts that an RPC will produce particular types of progeny, clonal lineage analysis was used to investigate the progeny of a subset of RPCs, those that express the basic helix–loop–helix transcription factor, Olig2. The embryonic Olig2+ RPCs underwent terminal divisions, producing small clones with primarily two of the five cell types being made by the pool of RPCs at that time. The later, postnatal Olig2+ RPCs also made terminal divisions, which were biased toward production of rod photoreceptors and amacrine cell interneurons. These data indicate that the multipotent progenitor pool is made up of distinctive types of RPCs, which have biases toward producing subsets of retinal neurons in a terminal division, with the types of neurons produced varying over time. This strategy is similar to that of the developing Drosophila melanogaster ventral nerve cord, with the Olig2+ cells behaving as ganglion mother cells.
Purpose
SARS-CoV-2 is a new pandemic influenza caused by a coronavirus which main route of transmission is through exhaled droplets that primarily infect the nose and the nasopharynx. The aim of this ...paper is to evaluate the effect of acetic acid, the active component of vinegar, as a potential disinfectant agent for upper airways.
Methods
Twenty-nine patients were enrolled and divided into two groups: group 1 (14 patients) was composed of patients treated with off-label hydroxychloroquine and lopinavir/ritonavir, whereas group 2 (15 patients) was composed of patients treated with hydroxychloroquine only, combined with the inhalation of acetic acid disinfectant at a 0.34% concentration. A questionnaire-based evaluation of symptoms was performed after 15 days in both groups.
Results
It appears that the number of patients treated with acetic acid (group 2) that experienced improvement in individual symptoms was double that of the other group of patients (group 1), although numbers are too small for robust statistical analysis.
Conclusions
Considering its potential benefits and high availability, acetic acid disinfection appears to be a promising adjunctive therapy in cases of non-severe COVID-19 and deserves further investigation.
Cocaine abuse occasionally causes extensive destruction of the osteocartilaginous structures of the nose, sinuses and palate, which mimics the clinical picture of other diseases associated with ...necrotising midfacial lesions. The differentiation of cocaine-induced midline destructive lesions (CIMDL) and limited granulomatosis with polyangiitis (GPA) may be difficult, particularly if patients do not readily admit substance abuse. We studied 10 patients with CIMDL and palate perforation referred to our Unit between 2002 and 2015. All cases underwent nasal endoscopy, sinus CT or MRI and ANCA test. In 8 patients, a nasal biopsy was performed. The PubMed database was searched to review all cases of palate perforation described in patients affected by CIMDL or GPA. All 10 cases presented with septal perforation and inferior turbinate destruction. We found hard palate perforation in 7 patients, soft palate perforation in 2 patients, and perforation of both in one patient. ANCA testing was negative in 8 patients and positive in 2, with C-ANCA and P-ANCA specificity, respectively. A review of the English literature identified palate perforation in 5 patients with GPA and in 73 patients with CIMDL. The presence of palate perforation in patients with MDL may represent a clinical marker that strongly favors CIMDL over GPA.
To better understand the mechanisms that govern the development of retinal neurons, it is critical to gain additional insight into the specific intrinsic factors that control cell fate decisions and ...neuronal maturation. In the developing mouse retina, Atoh7, a highly conserved transcription factor, is essential for retinal ganglion cell development. Moreover, Atoh7 expression in the developing retina occurs during a critical time period when progenitor cells are in the process of making cell fate decisions. We performed transcriptome profiling of Atoh7+ individual cells isolated from mouse retina. One of the genes that we found significantly correlated with Atoh7 in our transcriptomic data was the E3 ubiquitin ligase, Trim9. The correlation between Trim9 and Atoh7 coupled with the expression of Trim9 in the early mouse retina led us to hypothesize that this gene may play a role in the process of cell fate determination. To address the role of Trim9 in retinal development, we performed a functional analysis of Trim9 in the mouse and did not detect any morphological changes in the retina in the absence of Trim9. Thus, Trim9 alone does not appear to be involved in cell fate determination or early ganglion cell development in the mouse retina. We further hypothesize that the reason for this lack of phenotype may be compensation by one of the many additional TRIM family members we find expressed in the developing retina.
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