Histopathological features in fatal COVID-19 acute respiratory distress syndrome
Merdji, H;Mayeur, S;Schenck, M;Oulehri, W;Clere-Jehl, R;Cunat, S;Herbrecht, JE;Janssen-Langenstein, R;Nicolae, A;Helms, J;Meziani, F;Chenard, MP;CRICS TRIGGERSEP Group (Clinical Research in Intensive Care, Sepsis Trial Group for Global Evaluation, Research in Sepsis), ;
PMID: 34059216 | DOI: 10.1016/j.medine.2021.02.005
COVID-19 acute respiratory distress syndrome (ARDS) shares the common histological hallmarks with other forms of ARDS. However, the chronology of the histological lesions has not been well established.To describe the chronological histopathological alterations in the lungs of patients with COVID-19 related ARDS.A prospective cohort study was carried out.Intensive Care Unit of a tertiary hospital.The first 22 consecutive COVID-19 deaths.Lung biopsies and histopathological analyses were performed in deceased patients with COVID-19 related ARDS. Clinical data and patient course were evaluated.The median patient age was 66 [63-74] years; 73% were males. The median duration of mechanical ventilation was 17 [8-24] days. COVID-19 induced pulmonary injury was characterized by an exudative phase in the first week of the disease, followed by a proliferative/organizing phase in the second and third weeks, and finally an end-stage fibrosis phase after the third week. Viral RNA and proteins were detected in pneumocytes and macrophages in a very early stage of the disease, and were no longer detected after the second week.Limited sample size.The chronological evolution of COVID-19 lung histopathological lesions seems to be similar to that seen in other forms of ARDS. In particular, lung lesions consistent with potentially corticosteroid-sensitive lesions are seen.
Heightened activation of embryonic megakaryocytes causes aneurysms in the developing brain of mice lacking podoplanin
Hoover, CM;Kondo, Y;Shao, B;McDaniel, M;Lee, R;McGee, S;Whiteheart, SW;Bergmeier, W;McEver, RP;Xia, L;
PMID: 33619517 | DOI: 10.1182/blood.2020010310
During early embryonic development in mammals, including humans and mice, megakaryocytes first originate from primitive hematopoiesis in the yolk sac. These embryonic megakaryocytes (eMk) circulate in the vasculature with unclear function. Here we report that podoplanin (PDPN), the ligand of C-type lectin-like receptor (CLEC-2) on megakaryocytes/platelets, is temporarily expressed in neural tissue during midgestation in mice. Loss of PDPN or CLEC-2 resulted in aneurysms and spontaneous hemorrhage specifically in the lower diencephalon during midgestation. Surprisingly, more eMks/platelets had enhanced granule release and localized to lower diencephalon in mutant mouse embryos than wild-type littermates prior to hemorrhage. We found that PDPN counteracted the collagen I-induced secretion of angiopoietin-1 from fetal megakaryocytes, which coincided with enhanced TIE2 activation in aneurysm-like sprouts of PDPN-deficient embryos. Blocking platelet activation prevented the PDPN-deficient embryo from developing vascular defects. Our data reveal a new role for PDPN in regulating eMk function during midgestation.
Whole-body senescent cell clearance alleviates age-related brain inflammation and cognitive impairment in mice
Ogrodnik, M;Evans, SA;Fielder, E;Victorelli, S;Kruger, P;Salmonowicz, H;Weigand, BM;Patel, AD;Pirtskhalava, T;Inman, CL;Johnson, KO;Dickinson, SL;Rocha, A;Schafer, MJ;Zhu, Y;Allison, DB;von Zglinicki, T;LeBrasseur, NK;Tchkonia, T;Neretti, N;Passos, JF;Kirkland, JL;Jurk, D;
PMID: 33470505 | DOI: 10.1111/acel.13296
Cellular senescence is characterized by an irreversible cell cycle arrest and a pro-inflammatory senescence-associated secretory phenotype (SASP), which is a major contributor to aging and age-related diseases. Clearance of senescent cells has been shown to improve brain function in mouse models of neurodegenerative diseases. However, it is still unknown whether senescent cell clearance alleviates cognitive dysfunction during the aging process. To investigate this, we first conducted single-nuclei and single-cell RNA-seq in the hippocampus from young and aged mice. We observed an age-dependent increase in p16Ink4a senescent cells, which was more pronounced in microglia and oligodendrocyte progenitor cells and characterized by a SASP. We then aged INK-ATTAC mice, in which p16Ink4a -positive senescent cells can be genetically eliminated upon treatment with the drug AP20187 and treated them either with AP20187 or with the senolytic cocktail Dasatinib and Quercetin. We observed that both strategies resulted in a decrease in p16Ink4a exclusively in the microglial population, resulting in reduced microglial activation and reduced expression of SASP factors. Importantly, both approaches significantly improved cognitive function in aged mice. Our data provide proof-of-concept for senolytic interventions' being a potential therapeutic avenue for alleviating age-associated cognitive impairment.
Single-cell RNA sequencing reveals intratumoral heterogeneity in primary uveal melanomas and identifies HES6 as a driver of the metastatic disease
Cell death and differentiation
Pandiani, C;Strub, T;Nottet, N;Cheli, Y;Gambi, G;Bille, K;Husser, C;Dalmasso, M;Béranger, G;Lassalle, S;Magnone, V;Pédeutour, F;Irondelle, M;Maschi, C;Nahon-Estève, S;Martel, A;Caujolle, JP;Hofman, P;LeBrigand, K;Davidson, I;Baillif, S;Barbry, P;Ballotti, R;Bertolotto, C;
PMID: 33462406 | DOI: 10.1038/s41418-020-00730-7
Intratumor heterogeneity has been recognized in numerous cancers as a major source of metastatic dissemination. In uveal melanomas, the existence and identity of specific subpopulations, their biological function and their contribution to metastasis remain unknown. Here, in multiscale analyses using single-cell RNA sequencing of six different primary uveal melanomas, we uncover an intratumoral heterogeneity at the genomic and transcriptomic level. We identify distinct transcriptional cell states and diverse tumor-associated populations in a subset of the samples. We also decipher a gene regulatory network underlying an invasive and poor prognosis state driven in part by the transcription factor HES6. HES6 heterogenous expression has been validated by RNAscope assays within primary human uveal melanomas, which further unveils the existence of these cells conveying a dismal prognosis in tumors diagnosed with a favorable outcome using bulk analyses. Depletion of HES6 impairs proliferation, migration and metastatic dissemination in vitro and in vivo using the chick chorioallantoic membrane assay, demonstrating the essential role of HES6 in uveal melanomas. Thus, single-cell analysis offers an unprecedented view of primary uveal melanoma heterogeneity, identifies bona fide biomarkers for metastatic cells in the primary tumor, and reveals targetable modules driving growth and metastasis formation. Significantly, our findings demonstrate that HES6 is a valid target to stop uveal melanoma progression.
A role for orphan nuclear receptor liver receptor homolog-1 (LRH-1, NR5A2) in primordial follicle activation
Meinsohn, MC;Hughes, CHK;Estienne, A;Saatcioglu, HD;Pépin, D;Duggavathi, R;Murphy, BD;
PMID: 33441767 | DOI: 10.1038/s41598-020-80178-4
Liver receptor homolog-1 (NR5A2) is expressed specifically in granulosa cells of developing ovarian follicles where it regulates the late stages of follicle development and ovulation. To establish its effects earlier in the trajectory of follicular development, NR5A2 was depleted from granulosa cells of murine primordial and primary follicles. Follicle populations were enumerated in neonates at postnatal day 4 (PND4) coinciding with the end of the formation of the primordial follicle pool. The frequency of primordial follicles in PND4 conditional knockout (cKO) ovaries was greater and primary follicles were substantially fewer relative to control (CON) counterparts. Ten-day in vitro culture of PND4 ovaries recapitulated in vivo findings and indicated that CON mice developed primary follicles in the ovarian medulla to a greater extent than did cKO animals. Two subsets of primordial follicles were observed in wildtype ovaries: one that expressed NR5A2 and the second in which the transcript was absent. Neither expressed the mitotic marker. KI-67, indicating their developmental quiescence. RNA sequencing on PND4 demonstrated that loss of NR5A2 induced changes in 432 transcripts, including quiescence markers, inhibitors of follicle activation, and regulators of cellular migration and epithelial-to-mesenchymal transition. These experiments suggest that NR5A2 expression poises primordial follicles for entry into the developing pool.
Short prolactin isoforms are expressed in photoreceptors of canine retinas undergoing retinal degeneration
Sudharsan, R;Murgiano, L;Tang, HY;Olsen, TW;Chavali, VRM;Aguirre, GD;Beltran, WA;
PMID: 33432105 | DOI: 10.1038/s41598-020-80691-6
Prolactin (PRL) hormone functions as a pleiotropic cytokine with a protective role in the retina. We recently identified by transcriptome profiling that PRL is one of the most highly upregulated mRNAs in the retinas of mutant rcd1 (PDE6B) and xlpra2 (RPGR) dogs at advanced stages of photoreceptor disease. In the present study, we have identified the expression of a short PRL isoform that lacks exon 1 in canine retinas and analyzed the time-course of expression and localization of this isoform in the retinas of these two models. Using laser capture microdissection to isolate RNA from each of the retinal cellular layers, we found by qPCR that this short PRL isoform is expressed in photoreceptors of degenerating retinas. We confirmed by in situ hybridization that its expression is localized to the outer nuclear layer and begins shortly after the onset of disease at the time of peak photoreceptor cell death in both models. PRL protein was also detected only in mutant dog retinas. Our results call for further investigations into the role of this novel PRL isoform in retinal degeneration.
High spatial resolution mapping of the mucosal proteome of the gills of Crassostrea virginica: implication in particle processing
The Journal of experimental biology
Pales Espinosa, E;Allam, B;
PMID: 33431594 | DOI: 10.1242/jeb.233361
In the oyster Crassostrea virginica, the organization of the gill allows bidirectional particle transport where a dorsal gill tract directs particles meant to be ingested while a ventral tract collects particles intended to be rejected as pseudofeces. Previous studies showed that the transport of particles in both tracts is mediated by mucus. Consequently, we hypothesized that the nature and/or the quantity of mucosal proteins present in each tract is likely different. Using endoscopy-aided micro-sampling of mucus from each tract followed by multidimensional protein identification technologies, and in situ hybridization, a high spatial resolution mapping of the oyster gill proteome was generated. Results showed the presence in gill mucus of a wide range of molecules involved in non-self recognition and interactions with microbes. Mucus composition was different between the two tracts, with mucus from the ventral tract shown to be rich in mucin-like proteins, providing an explanation of its high viscosity, while mucus from the dorsal tract was found to be enriched in mannose-binding proteins, known to be involved in food particle binding and selection. Overall, this study generated high-resolution proteomes for C. virginica gill mucus and demonstrated that the contrasting functions of the two pathways present on oyster gills are associated with significant differences in their protein makeup.
International journal of molecular sciences
Zong, YJ;Liu, XZ;Tu, L;Sun, Y;
PMID: 37373495 | DOI: 10.3390/ijms241210349
The connexin gene family is the most prevalent gene that contributes to hearing loss. Connexins 26 and 30, encoded by GJB2 and GJB6, respectively, are the most abundantly expressed connexins in the inner ear. Connexin 43, which is encoded by GJA1, appears to be widely expressed in various organs, including the heart, skin, the brain, and the inner ear. The mutations that arise in GJB2, GJB6, and GJA1 can all result in comprehensive or non-comprehensive genetic deafness in newborns. As it is predicted that connexins include at least 20 isoforms in humans, the biosynthesis, structural composition, and degradation of connexins must be precisely regulated so that the gap junctions can properly operate. Certain mutations result in connexins possessing a faulty subcellular localization, failing to transport to the cell membrane and preventing gap junction formation, ultimately leading to connexin dysfunction and hearing loss. In this review, we provide a discussion of the transport models for connexin 43, connexins 30 and 26, mutations affecting trafficking pathways of these connexins, the existing controversies in the trafficking pathways of connexins, and the molecules involved in connexin trafficking and their functions. This review can contribute to a new way of understanding the etiological principles of connexin mutations and finding therapeutic strategies for hereditary deafness.
Salvador, AFM;Dykstra, T;Rustenhoven, J;Gao, W;Blackburn, SM;Bhasiin, K;Dong, MQ;Guimarães, RM;Gonuguntla, S;Smirnov, I;Kipnis, J;Herz, J;
PMID: 37148871 | DOI: 10.1016/j.neuron.2023.04.011
Spinal cord injury (SCI) causes lifelong debilitating conditions. Previous works demonstrated the essential role of the immune system in recovery after SCI. Here, we explored the temporal changes of the response after SCI in young and aged mice in order to characterize multiple immune populations within the mammalian spinal cord. We revealed substantial infiltration of myeloid cells to the spinal cord in young animals, accompanied by changes in the activation state of microglia. In contrast, both processes were blunted in aged mice. Interestingly, we discovered the formation of meningeal lymphatic structures above the lesion site, and their role has not been examined after contusive injury. Our transcriptomic data predicted lymphangiogenic signaling between myeloid cells in the spinal cord and lymphatic endothelial cells (LECs) in the meninges after SCI. Together, our findings delineate how aging affects the immune response following SCI and highlight the participation of the spinal cord meninges in supporting vascular repair.
Ruohan, Z;Yicheng, B;Jingying, Z;Mei, H;Xinyan, Z;Min, Y;Tengfei, D;Junjing, J;
| DOI: 10.1080/26895293.2023.2199140
In summary, with the continuous improvement of technology and methods, scRNA-seq is becoming an indispensable tool in many biomedical fields. It is predicted that single-cell multiplex technology will play a more powerful role in single-cell research of complex organs and tissues in the future. It is expected that the demand and application of scRNA-seq technology will increase greatly in the future, and the technology will become more refined, high-throughput, affordable, and easier to use in scientific research laboratories and clinical laboratories. Especially in the new era of precision medicine, the study of the characteristics of high intercellular heterogeneity and clonal evolution in the occurrence, development, and treatment of diseases brings hope for the accurate diagnosis and treatment of diseases. In particular, it can be used to monitor the progress, efficacy, and prognosis of hematological tumors, and is likely to find potential therapeutic targets, providing a basis for accurate diagnosis, dynamic monitoring, and individualized treatment of the disease. More importantly, innovative single-cell technology is expected to greatly promote the effective control of diseases in IVF and early pregnancy screening and diagnosis of chromosomal and genetic diseases by improving the efficiency and detection quality. Thus, scRNA-seq is of great significance to improve human genetic health.
Song, H;Morrow, BE;
PMID: 36521641 | DOI: 10.1016/j.ydbio.2022.12.003
The morphogenesis of the otic vesicle (OV) to form inner ear organs serves as an excellent model system to understand cell fate acquisition on a single cell level. Tbx2 and Tbx3 (Tbx2/3) encode closely related T-box transcription factors that are expressed widely in the mammalian OV. Inactivation of both genes in the OV (Tbx2/3cKO) results in failed morphogenesis into inner ear organs. To understand the basis of these defects, single cell RNA-sequencing (scRNA-seq) was performed on the OV lineage, in controls versus Tbx2/3cKO embryos. We identified a multipotent population termed otic progenitors in controls that are marked by expression of the known otic placode markers Eya1, Sox2, and Sox3 as well as new markers Fgf18, Cxcl12, and Pou3f3. The otic progenitor population was increased three-fold in Tbx2/3cKO embryos, concomitant with dysregulation of genes in these cells as well as reduced progression to more differentiated states of prosensory and nonsensory cells. An ectopic neural population of cells was detected in the posterior OV of Tbx2/3cKO embryos but had reduced maturation to delaminated neural cells. As all three cell fates were affected in Tbx2/3cKO embryos, we suggest that Tbx2/3 promotes progression of multipotent otic progenitors to more differentiated cell types in the OV.
Gregor, KM;Becker, SC;Hellhammer, F;Baumgärtner, W;Puff, C;
PMID: 35053056 | DOI: 10.3390/biology11010057
Arthropod-borne diseases represent one of the greatest infection-related threats as a result of climate change and globalization. Repeatedly, arbovirus-infected mosquitoes show behavioral changes whose underlying mechanisms are still largely unknown, but might help to develop control strategies. However, in contrast to well-characterized insects such as fruit flies, little is known about neuroanatomy and neurotransmission in mosquitoes. To overcome this limitation, the study focuses on the immunohistochemical characterization of the nervous system of Culex pipiens biotype molestus in comparison to Drosophila melanogaster using 13 antibodies labeling nervous tissue, neurotransmitters or neurotransmitter-related enzymes. Antibodies directed against γ-aminobutyric acid, serotonin, tyrosine-hydroxylase and glutamine synthetase were suitable for investigations in Culex pipiens and Drosophila melanogaster, albeit species-specific spatial differences were observed. Likewise, similar staining results were achieved for neuronal glycoproteins, axons, dendrites and synaptic zones in both species. Interestingly, anti-phosphosynapsin and anti-gephyrin appear to represent novel markers for synapses and glial cells, respectively. In contrast, antibodies directed against acetylcholine, choline acetyltransferase, elav and repo failed to produce a signal in Culex pipiens comparable to that in Drosophila melanogaster. In summary, present results enable a detailed investigation of the nervous system of mosquitoes, facilitating further studies of behavioral mechanisms associated with arboviruses in the course of vector research.