Yao, Y;Chen, J;Li, X;Chen, ZF;Li, P;
PMID: 36750092 | DOI: 10.1016/j.cub.2023.01.019
Increased ventilation is a critical process that occurs when the body responds to a hypoxic environment. Sighs are long, deep breaths that prevent alveolar collapse, and their frequency is significantly increased by hypoxia. In this study, we first show that sighing is induced by hypoxia as a function of increased hypoxic severity and that hypoxia-induced sighing is capable of increasing the oxygen saturation in a mouse model. We next found that the gastrin-releasing peptide (Grp) expressing neurons in the nucleus of the solitary tract (NTS) are important in mediating hypoxia-induced sighing. Retrograde tracing from these Grp neurons reveals their direct afferent input from the petrosal ganglion neurons that innervate the carotid body, the major peripheral chemoreceptor that senses blood oxygen. Acute hypoxia preferentially activates these Grp neurons in the NTS. Photoactivation of these neurons through their projections in the inspiratory rhythm generator in the ventral medulla induces sighing, whereas genetic ablation or chemogenetic silencing of these neurons specifically diminishes the sighs, but not other respiratory responses, induced by hypoxia. Finally, the mice with reduced sighing in hypoxia exhibit an elevated heart-rate increase, which may compensate for maintaining the blood oxygen level. Therefore, we identified a neural circuit that connects the carotid body to the breathing control center in the ventral medulla with a specific function for hypoxia-induced sighing, which restores the oxygen level.
Leithead, AB;Godino, A;Barbier, M;Harony-Nicolas, H;
PMID: 37245781 | DOI: 10.1016/j.biopsych.2023.05.016
The posterior intralaminar (PIL) complex of the thalamus is a multimodal nucleus that has been implicated in maternal behaviors and conspecific social behaviors in male and female rodents. Glutamatergic neurons are a major component of the PIL; however, their specific activity and role during social interactions has not yet been assessed.We used immunohistochemistry for the immediate early gene c-fos as a proxy for neuronal activity in the PIL of mice exposed to a novel social stimulus, a novel object stimulus, or no stimulus. We then used fiber photometry to record neural activity of glutamatergic neurons in the PIL in real-time during social and non-social interactions. Finally, we used inhibitory DREADDs in glutamatergic PIL neurons and tested social preference and social habituation-dishabituation.We observed significantly more c-fos-positive cells in the PIL of mice exposed to social versus object or no stimuli. Neural activity of PIL glutamatergic neurons was increased when male and female mice were engaged in social interaction with a same-sex juvenile or opposite-sex adult, but not a toy mouse. Neural activity positively correlated with social investigation bout length and negatively correlated with chronological order of bouts. Social preference was unaffected by inhibition; however, inhibiting activity of glutamatergic neurons in the PIL delayed the time it took female mice to form social habituation.Together these findings suggest that glutamatergic PIL neurons respond to social stimuli in both male and female mice and may regulate perceptual encoding of social information to facilitate recognition of social stimuli.
Fabre PJ, Leleu M, Mascrez B, Lo Giudice Q, Cobb J, Duboule D.
PMID: 30223853 | DOI: 10.1186/s12915-018-0570-z
Abstract
BACKGROUND:
Global analyses of gene expression during development reveal specific transcription patterns associated with the emergence of various cell types, tissues, and organs. These heterogeneous patterns are instrumental to ensure the proper formation of the different parts of our body, as shown by the phenotypic effects generated by functional genetic approaches. However, variations at the cellular level can be observed within each structure or organ. In the developing mammalian limbs, expression of Hox genes from the HoxD cluster is differentially controlled in space and time, in cells that will pattern the digits and the forearms. While the Hoxd genes broadly share a common regulatory landscape and large-scale analyses have suggested a homogenous Hox gene transcriptional program, it has not previously been clear whether Hoxd genes are expressed together at the same levels in the same cells.
RESULTS:
We report a high degree of heterogeneity in the expression of the Hoxd11 and Hoxd13 genes. We analyzed single-limb bud cell transcriptomes and show that Hox genes are expressed in specific combinations that appear to match particular cell types. In cells giving rise to digits, we find that the expression of the five relevant Hoxd genes (Hoxd9 to Hoxd13) is unbalanced, despite their control by known global enhancers. We also report that specific combinatorial expression follows a pseudo-time sequence, which is established based on the transcriptional diversity of limb progenitors.
CONCLUSIONS:
Our observations reveal the existence of distinct combinations of Hoxd genes at the single-cell level during limb development. In addition, we document that the increasing combinatorial expression of Hoxd genes in this developing structure is associated with specific transcriptional signatures and that these signatures illustrate a temporal progression in the differentiation of these cells.
Kamitakahara A, Wu HH, Levitt P.
PMID: 28758209 | DOI: 10.1002/cne.24294
Detailed anatomical tracing and mapping of the viscerotopic organization of the vagal motor nuclei has provided insight into autonomic function in health and disease. To further define specific cellular identities, we paired information based on visceral connectivity with a cell-type specific marker of a subpopulation of neurons in the dorsal motor nucleus of the vagus (DMV) and nucleus ambiguus (nAmb) that express the autism-associated MET receptor tyrosine kinase. As gastrointestinal disturbances are common in children with autism spectrum disorder (ASD), we sought to define the relationship between MET-expressing (MET+) neurons in the DMV and nAmb, and the gastrointestinal tract. Using wholemount tissue staining and clearing, or retrograde tracing in a METEGFP transgenic mouse, we identify three novel subpopulations of EGFP+ vagal brainstem neurons: 1) EGFP+ neurons in the nAmb projecting to the esophagus or laryngeal muscles, 2) EGFP+ neurons in the medial DMV projecting to the stomach, and 3) EGFP+ neurons in the lateral DMV projecting to the cecum and/or proximal colon. Expression of the MET ligand, hepatocyte growth factor (HGF), by tissues innervated by vagal motor neurons during fetal development reveal potential sites of HGF-MET interaction. Furthermore, similar cellular expression patterns of MET in the brainstem of both the mouse and nonhuman primate suggest that MET expression at these sites is evolutionarily conserved. Together, the data suggest that MET+ neurons in the brainstem vagal motor nuclei are anatomically positioned to regulate distinct portions of the gastrointestinal tract, with implications for the pathophysiology of gastrointestinal comorbidities of ASD.
Dis Model Mech. 2019 Jan 14.
Jones W Jr, Rodriguez J, Bassnett S.
PMID: PMID: 30642872 | DOI: DOI:10.1242/dmm.037283
Fibrillin is an evolutionarily ancient protein that lends elasticity and resiliency to a variety of tissues. In humans, mutations in fibrillin-1 cause Marfan and related syndromes, conditions in which the eye is often severely affected. To gain insights into the ocular sequelae of Marfan syndrome, we targeted Fbn1 in mouse lens or non-pigmented ciliary epithelium (NPCE). Conditional knockout of Fbn1 in NPCE, but not lens, profoundly affected the ciliary zonule, the system of fibrillin-rich fibers that centers the lens in the eye. The tensile strength of the fibrillin-depleted zonule was reduced substantially, due to a shift toward production of smaller caliber fibers. By three months, zonular fibers invariably ruptured and mice developed ectopia lentis, a hallmark of Marfan syndrome. At later stages, untethered lenses lost their polarity and developed cataracts, and the length and volume of mutant eyes increased. This model thus captures key aspects of Marfan-related syndromes, providing insights into the role of fibrillin-1 in eye development and disease.
Human Type II Taste Cells Express ACE2 and are Infected by SARS-CoV-2
The American journal of pathology
Doyle, ME;Appleton, A;Liu, QR;Yao, Q;Mazucanti, CH;Egan, JM;
PMID: 34102107 | DOI: 10.1016/j.ajpath.2021.05.010
Chemosensory changes are well-reported symptoms of SARS-CoV-2 infection. The virus targets cells for entry by binding of its spike protein to cell-surface angiotensin-converting enzyme- 2 (ACE2). It was not known whether ACE2 is expressed on taste receptor cells (TRCs) nor if TRCs are infected directly. Using an in-situ hybridization (ISH) probe and an antibody specific to ACE2, ACE2 is present on a subpopulation of TRCs, namely, Type II cells in taste buds in taste papillae. Fungiform papillae (FP) of a SARS-CoV-2+ patient exhibiting symptoms of COVID-19, including taste changes, were biopsied. Based on ISH, replicating SARS-CoV-2 was present in Type II cells. Therefore, taste Type II cells provide a potential portal for viral entry that predicts vulnerabilities to SARS-CoV-2 in the oral cavity. The continuity and cell turnover of the patient's FP taste stem cell layer were disrupted during infection and had not completely recovered 6 weeks post symptom onset. Another patient suffering post-COVID-19 taste disturbances also had disrupted stem cells. These results demonstrate the possibility that novel and sudden taste changes frequently reported in COVID-19 may be the result of direct infection of taste papillae by SARS-CoV-2. This may result in impaired taste receptor stem cell activity and suggest more work is needed to understand the acute and post-acute dynamics of viral kinetics in the human taste bud.
Robustelli Test, E;Sena, P;Locatelli, AG;Carugno, A;di Mercurio, M;Moggio, E;Gambini, DM;Arosio, MEG;Callegaro, A;Morotti, D;Gianatti, A;Vezzoli, P;
PMID: 34989043 | DOI: 10.1111/pde.14903
Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, an increasing number of chilblain-like lesions (ChLL) have been increasingly reported worldwide. To date, the causal link between ChLL and SARS-CoV-2 infection has not been unequivocally established.In this case series, we present demographic, clinical, laboratory, and histopathological information regarding 27 young patients with a clinical diagnosis of ChLL who referred to the Dermatology Unit of Papa Giovanni XXIII Hospital, Bergamo, Italy, from 1 April 2020 to 1 June 2020.The mean age was 14.2 years, and 21 patients (78%) experienced mild systemic symptoms a median of 28 days before the onset of cutaneous lesions. ChLL mostly involved the feet (20 patients - 74%). Among acral lesions, we identified three different clinical patterns: (i) chilblains in 20 patients (74%); (ii) fixed erythematous macules in 4 children (15%); (iii) erythrocyanosis in 3 female patients (11%). Blood examinations and viral serologies, including parvovirus B19, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and coxsackievirus were normal in all. Three patients (11%) underwent nasopharyngeal swab for RT-PCR for SARS-CoV-2 showing only 1 positive. Histopathological examinations of 7 skin biopsies confirmed the clinical diagnosis of chilblains; vessel thrombi were observed only in 1 case. Our findings failed to demonstrate the direct presence of SARS-CoV-2 RNA in skin biopsies, both with real-time polymerase chain reaction (RT-PCR) and RNAscope in situ hybridization (ISH).Limited number of cases, unavailability of laboratory confirmation of COVID-19 in all patients, potential methodological weakness, and latency of skin biopsies in comparison to cutaneous lesions onset.These observations may support the hypothesis of an inflammatory pathogenesis rather than the presence of peripheral viral particles. Although, we could not exclude an early phase of viral endothelial damage followed by an IFN-I or complement-mediated inflammatory phase. Further observations on a large number of patients are needed to confirm this hypothesis.
Viral mapping in COVID-19 deceased in the Augsburg autopsy series of the first wave: A multiorgan and multimethodological approach
Hirschbühl, K;Dintner, S;Beer, M;Wylezich, C;Schlegel, J;Delbridge, C;Borcherding, L;Lippert, J;Schiele, S;Müller, G;Moiraki, D;Spring, O;Wittmann, M;Kling, E;Braun, G;Kröncke, T;Claus, R;Märkl, B;Schaller, T;
PMID: 34280238 | DOI: 10.1371/journal.pone.0254872
COVID-19 is only partly understood, and the level of evidence available in terms of pathophysiology, epidemiology, therapy, and long-term outcome remains limited. During the early phase of the pandemic, it was necessary to effectively investigate all aspects of this new disease. Autopsy can be a valuable procedure to investigate the internal organs with special techniques to obtain information on the disease, especially the distribution and type of organ involvement.During the first wave of COVID-19 in Germany, autopsies of 19 deceased patients were performed. Besides gross examination, the organs were analyzed with standard histology and polymerase-chain-reaction for SARS-CoV-2. Polymerase chain reaction positive localizations were further analyzed with immunohistochemistry and RNA-in situ hybridization for SARS-CoV-2.Eighteen of 19 patients were found to have died due to COVID-19. Clinically relevant histological changes were only observed in the lungs. Diffuse alveolar damage in considerably different degrees was noted in 18 cases. Other organs, including the central nervous system, did not show specific micromorphological alterations. In terms of SARS-CoV-2 detection, the focus remains on the upper airways and lungs. This is true for both the number of positive samples and the viral load. A highly significant inverse correlation between the stage of diffuse alveolar damage and viral load was found on a case and a sample basis. Mediastinal lymph nodes and fat were also affected by the virus at high frequencies. By contrast, other organs rarely exhibited a viral infection. Moderate to strong correlations between the methods for detecting SARS-CoV-2 were observed for the lungs and for other organs.The lung is the most affected organ in gross examination, histology and polymerase chain reaction. SARS-CoV-2 detection in other organs did not reveal relevant or specific histological changes. Moreover, we did not find CNS involvement.
WNT7B Regulates Cholangiocyte Proliferation and Function During Murine Cholestasis
Hepatology communications
Kosar, K;Cornuet, P;Singh, S;Lee, E;Liu, S;Gayden, J;Sato, T;Freyberg, Z;Arteel, G;Nejak-Bowen, K;
PMID: 34558852 | DOI: 10.1002/hep4.1784
We previously identified an up-regulation of specific Wnt proteins in the cholangiocyte compartment during cholestatic liver injury and found that mice lacking Wnt secretion from hepatocytes and cholangiocytes showed fewer proliferating cholangiocytes and high mortality in response to a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet, a murine model of primary sclerosing cholangitis. In vitro studies demonstrated that Wnt7b, one of the Wnts up-regulated during cholestasis, induces proliferation of cholangiocytes in an autocrine manner and increases secretion of proinflammatory cytokines. We hypothesized that loss of Wnt7b may exacerbate some of the complications of cholangiopathies by decreasing the ability of bile ducts to induce repair. Wnt7b-flox mice were bred with Krt19-cre mice to deplete Wnt7b expression in only cholangiocytes (CC) or with albumin-Cre mice to delete Wnt7b expression in both hepatocytes and cholangiocytes (HC + CC). These mice were placed on a DDC diet for 1 month then killed for evaluation. Contrary to our expectations, we found that mice lacking Wnt7b from CC and HC + CC compartments had improved biliary injury, decreased cellular senescence, and lesser bile acid accumulation after DDC exposure compared to controls, along with decreased expression of inflammatory cytokines. Although Wnt7b knockout (KO) resulted in fewer proliferating cholangiocytes, CC and HC + CC KO mice on a DDC diet also had more hepatocytes expressing cholangiocyte markers compared to wild-type mice on a DDC diet, indicating that Wnt7b suppression promotes hepatocyte reprogramming. Conclusion: Wnt7b induces a proproliferative proinflammatory program in cholangiocytes, and its loss is compensated for by conversion of hepatocytes to a biliary phenotype during cholestatic injury.
Successful hemostasis of bleeding gastric inflammatory fibroid polyp by endoscopic treatment in a patient with severe COVID-19
Clinical journal of gastroenterology
Murota, A;Yoshi, S;Okuda, R;Oowada, S;Yamakawa, T;Kazama, T;Hirayama, D;Ishigami, K;Yamano, HO;Narimatu, E;Sugita, S;Hasegawa, T;Nakase, H;
PMID: 33840076 | DOI: 10.1007/s12328-021-01402-w
The coronavirus disease-2019 (COVID-19) has rapidly become a pandemic, resulting in a global suspension of non-emergency medical procedures such as screening endoscopic examinations. There have been several reports of COVID-19 patients presenting with gastrointestinal symptoms such as diarrhea and vomiting. In this report, we present a case of successful hemostasis of bleeding gastric inflammatory fibroid polyp by endoscopic treatment in a patient with severe COVID-19. The case was under mechanical ventilation with extracorporeal membrane oxygenation (ECMO), and the airway was on a closed circuit. This indicates that COVID-19 is associated with not only lung injury but also intestinal damage, and that proper protective protocols are essential in guaranteeing the best outcomes for patients and clinical professionals during this pandemic.
Polinski NK, Gombash SE, Manfredsson FP, Lipton JW, Kemp CJ, Cole-Strauss A, Kanaan NM, Steece-Collier K, Kuhn NC, Wohlgenant SL, Sortwell CE.
PMID: http
Clinical trials are examining the efficacy of viral vector-mediated gene delivery for treating Parkinson’s disease (PD). While viral vector strategies have been successful in preclinical studies, to date clinical trials have disappointed. This may be due to the fact that preclinical studies fail to account for aging. Aging is the single greatest risk factor for developing PD and age alters cellular processes utilized by viral vectors. We hypothesized that the aged brain would be relatively resistant to transduction when compared to the young adult. We examined recombinant adeno-associated virus 2/5 mediated green fluorescent protein (rAAV2/5 GFP) expression in the young adult and aged rat nigrostriatal system. GFP overexpression was produced in both age groups. However, following rAAV2/5 GFP injection to the substantia nigra (SN) aged rats displayed 40-60% less GFP protein in the striatum, regardless of rat strain or duration of expression. Further, aged rats exhibited 40% fewer cells expressing GFP and 4-fold less GFP mRNA. rAAV2/5-mediated gene transfer is compromised in the aged rat midbrain, with deficiencies in early steps of transduction leading to significantly less mRNA and protein expression.
Yu, P;Deng, W;Bao, L;Qu, Y;Xu, Y;Zhao, W;Han, Y;Qin, C;
PMID: 35094625 | DOI: 10.1177/03009858211071016
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes severe viral pneumonia and is associated with a high fatality rate. A substantial proportion of patients infected by SARS-CoV-2 suffer from mild hyposmia to complete loss of olfactory function, resulting in anosmia. However, the pathogenesis of the olfactory dysfunction and comparative pathology of upper respiratory infections with SARS-CoV-2 are unknown. We describe the histopathological, immunohistochemical, and in situ hybridization findings from rodent models of SARS-CoV-2 infection. The main histopathological findings in the olfactory epithelia of K8-hACE2 Tg mice, hACE2 Tg mice, and hamsters were varying degrees of inflammatory lesions, including disordered arrangement, necrosis, exfoliation, and macrophage infiltration of the olfactory epithelia, and inflammatory exudation. On the basis of these observations, the nasal epithelia of these rodent models appeared to develop moderate, mild, and severe rhinitis, respectively. Correspondingly, SARS-CoV-2 viral RNA and antigen were mainly identified in the olfactory epithelia and lamina propria. Moreover, viral RNA was abundant in the cerebrum of K18-hACE2 Tg mice, including the olfactory bulb. The K8-hACE2 Tg mouse, hACE2 Tg mouse, and hamster models could be used to investigate the pathology of SARS-CoV-2 infection in the upper respiratory tract and central nervous system. These models could help to provide a better understanding of the pathogenic process of this virus and to develop effective medications and prophylactic treatments.
