Mesoderm-specific Stat3 deletion affects expression of Sox9 yielding Sox9-dependent phenotypes.

To date, mutations within the coding region and translocations around the SOX9 gene both constitute the majority of genetic lesions underpinning human campomelic dysplasia (CD). While pathological coding-region mutations typically result in a non-functional SOX9 protein, little is known about what mechanism(s) controls normal SOX9 expression, and subsequently, which signaling pathways may be interrupted by alterations occurring around the SOX9 gene. Here, we report the identification of Stat3 as a key modulator of Sox9 expression in nascent cartilage and developing chondrocytes. Stat3 expression is predominant in tissues of mesodermal origin, and its conditional ablation using mesoderm-specific TCre, in vivo, causes dwarfism and skeletal defects characteristic of CD. Specifically, Stat3 loss results in the expansion of growth plate hypertrophic chondrocytes and deregulation of normal endochondral ossification in all bones examined. Conditional deletion of Stat3 with a Sox9Cre driver produces palate and tracheal irregularities similar to those described in Sox9+/- mice. Furthermore, mesodermal deletion of Stat3 causes global embryonic down regulation of Sox9 expression and function in vivo. Mechanistic experiments ex vivo suggest Stat3 can directly activate the expression of Sox9 by binding to its proximal promoter following activation. These findings illuminate a novel role for Stat3 in chondrocytes during skeletal development through modulation of a critical factor, Sox9. Importantly, they further provide the first evidence for the modulation of a gene product other than Sox9 itself which is capable of modeling pathological aspects of CD and underscore a potentially valuable therapeutic target for patients with the disorder.

YY1 is indispensable for Lgr5+ intestinal stem cell renewal.

The intestinal stem cell fuels the highest rate of tissue turnover in the body and has been implicated in intestinal disease and cancer; understanding the regulatory mechanisms controlling intestinal stem cell physiology is of great importance. Here, we provide evidence that the transcription factor YY1 is essential for intestinal stem cell renewal. We observe that YY1 loss skews normal homeostatic cell turnover, with an increase in proliferating crypt cells and a decrease in their differentiated villous progeny. Increased crypt cell numbers come at the expense of Lgr5(+) stem cells. On YY1 deletion, Lgr5(+) cells accelerate their commitment to the differentiated population, exhibit increased levels of apoptosis, and fail to maintain stem cell renewal. Loss of Yy1 in the intestine is ultimately fatal. Mechanistically, YY1 seems to play a role in stem cell energy metabolism, with mitochondrial complex I genes bound directly by YY1 and their transcript levels decreasing on YY1 loss. These unappreciated YY1 functions broaden our understanding of metabolic regulation in intestinal stem cell homeostasis.

A Case of Concurrent Disseminated Coccidioidomycosis and Embryonal Carcinoma When Lice and Fleas Coexist.

Coccidioidomycosis (CM) is a fungal infection endemic to the southwestern United States with a wide range of clinical presentations depending on the infected organ systems. Most infections are asymptomatic. Coccidioidomycosis causes a primary pulmonary infection and when symptoms occur, they most often resemble community-acquired pneumonia. One percent of cases disseminate, typically via hematogenous or lymphatic spread. It is in these cases that more severe symptoms may present and potentially overlap with those characteristics of other systemic illnesses. This is a case of CM disseminated to lymph nodes in a 24-year-old man with concomitant metastatic embryonal carcinoma. It is difficult to identify the primary etiology for many components of this patient's presentation, including diffuse lymphadenopathy and multiple pulmonary nodules. Furthermore, the relationship between these 2 concurrent disease processes is not entirely clear. Factors that may contribute include the well-known phenomenon of locus minoris resistentiae (LMR) or potentially a shared immune failure between infectious organisms and malignant cells.

A Double Whammy Pneumonia: The First Reported Case of Concurrent Neisseria meningitidis and SARS-CoV-2 Pneumonia.

Meningococcal pneumonia (MP) is a rare manifestation of meningococcal disease. The MP was first described in 1907 when Neisseria meningitidis (NM) isolates were identified in sputum samples obtained from soldiers with pneumonia. Preceding and concurrent viral infections constitute a major risk for MP. During the 1918-1919 influenza pandemic, a significant increase in MP cases were reported in patients with preceding influenza infection. Despite the end of the last H1N1 influenza pandemic in 2010, seasonal influenza infections still pose a risk for simultaneous MP. History appears to be repeating itself with concomitant bacterial and viral coinfection amid the current SARS-CoV-2 pandemic. Herein presented is a unique case of an elderly woman who presented with, to the best of our knowledge, the first reported case of possible concurrent SARS-CoV-2 and MP infections.

Acute Pericarditis Leading to a Diagnosis of SLE: A Case Series of 3 Patients.

In systemic lupus erythematosus (SLE), cardiac manifestations are known to be present in up to 50% of patients. However, it is rare for acute pericarditis to be the leading symptom at the time of diagnosis of SLE occurring in up to 1% of patients. We present a case series in which 3 patients with no prior history of SLE presented with acute pericarditis. This was found to be the leading manifestation of their disease, which ultimately led to the diagnosis of SLE. These patients were initially treated with nonsteroidal anti-inflammatory drugs and colchicines; however, steroids and disease-modifying anti-rheumatologic agents were ultimately added to their medical therapy.

A census of the lung: CellCards from LungMAP.

The human lung plays vital roles in respiration, host defense, and basic physiology. Recent technological advancements such as single-cell RNA sequencing and genetic lineage tracing have revealed novel cell types and enriched functional properties of existing cell types in lung. The time has come to take a new census. Initiated by members of the NHLBI-funded LungMAP Consortium and aided by experts in the lung biology community, we synthesized current data into a comprehensive and practical cellular census of the lung. Identities of cell types in the normal lung are captured in individual cell cards with delineation of function, markers, developmental lineages, heterogeneity, regenerative potential, disease links, and key experimental tools. This publication will serve as the starting point of a live, up-to-date guide for lung research at https://www.lungmap.net/cell-cards/. We hope that Lung CellCards will promote the community-wide effort to establish, maintain, and restore respiratory health.

Prolonged SARS-CoV2 Viral Shedding in an Elderly Patient.

Coronavirus disease 2019 (COVID-19) has been devastating to the elderly population, especially due to a lack of clear guidelines for treatment. Corticosteroids have been the mainstay in treating the cytokine storm caused by the virus. In the past, prolonged viral shedding of Middle East Respiratory Syndrome (MERS) was noted in patients treated with high-dose corticosteroids. It is unclear whether this also holds true for severe acute respiratory syndrome coronavirus (SARS-CoV2). To our knowledge, this case report highlights the longest reported disease course of SARS-CoV2, lasting approximately 210 days.

Locus Minoris Resistentiae: Two Cases of Malignant Metastasis and Review of Literature.

Locus minoris resistentiae refers to a region of decreased resistance within the body. This occurs from changes to the microenvironment secondary to previous trauma and results in increased vulnerability. As a result, infection, inflammatory processes, and malignancy may localize to this area. In this article, we describe 2 unique cases of malignancy, primary prostate carcinoma and serous carcinoma of the ovary, both of which disseminated to sites of prior trauma. We review the available literature, discuss proposed pathophysiology, and highlight the need for further investigations along with increased clinician awareness.

The First Case Report of Endocarditis Caused by Serratia fonticola.

The cases of human infections caused by Serratia fonticola are relatively rare. The few cases that have been reported primarily describe skin and soft tissue, urinary, and biliary tract infections. We describe a case of a 59-year-old man with infected bilateral lower extremity wounds who developed endocarditis due to S fonticola confirmed with transesophageal echocardiogram. The patient was treated with 6 weeks of antibiotic therapy and had an uneventful recovery. After a thorough review of the literature using PubMed and Google Scholar, we concluded that this is the first reported case of endocarditis caused by S fonticola.

Echocardiographic Findings in Heart Failure Patients With Methamphetamine Use: A Case-Control Study.

Background Methamphetamine use is associated with cardiovascular disease and significant morbidity and mortality. There is only one previous study performed on echocardiographic parameters in patients with methamphetamine cardiomyopathy. Methods We performed a retrospective review of medical records in a county hospital in Southern California with a high population of methamphetamine users. We reviewed medical records and echocardiogram findings in patients seen in our institution from November 2019 to November 2020 who had cardiomyopathy with and without methamphetamine use. We excluded patients who either left the hospital or expired before appropriate assessment. We divided our patient population into a case group (methamphetamine users) and a control group (non-methamphetamine users) to study and compare their echocardiographic parameters. Results Case group included a total of 254 patients and control group included 268 patients. Majority of the patient population were males - 178 (70%) and 180 (67%) in the case and control group respectively. Age was found to be statistically significant with the younger population in the case group (p = 0.0000). Our analysis revealed statistically significant difference in methamphetamine users compared to non-users in regards to left ventricle ejection fraction (33.65% ± 18.02 vs. 41.55% ± 15.61, p=0.0000), left ventricle mass index (122.49 grams/m2 ± 40.66 vs. 108.62 grams/m2 ± 32.82, p=0.0000), left ventricle end diastolic volume index (85.91 mL/m2 ± 37.40 vs. 72.44 mL/m2 ± 25.44; p=0.0000) and marginally significant right ventricle systolic pressure (42.29mmHg ± 17.53 vs. 39.59mmHg ± 15.61; p=0.0540) Conclusion Our results indicated that methamphetamine users had echocardiogram findings with decreased ejection fraction and increased left ventricular mass index, end-diastolic volume index, and right ventricular systolic pressure consistent with worse dilated cardiomyopathy comparison to non-users.

Wound Botulism in Black Tar Heroin Injecting Users: A Case Series.

The incidence of wound botulism in injection drug users has increased since the introduction of black tar heroin. Many species of the Clostridium genus, most commonly Clostridium botulinum, Clostridium baratii, and Clostridium butyricum, have been associated with wound botulism. Patients often present with progressive bulbar weakness, including dysphagia, cranial nerve palsies, and loss of speech, in addition to symmetrical descending weakness of the upper extremities that may progress to the chest and lower extremities. In this article, we present 3 cases of wound botulism, in which the patients presented with bulbar weakness and were treated with botulism antitoxin heptavalent. The time to antitoxin administration and its effect on the patients' clinical courses is compared.

A Case of Testicular Granulomatous Inflammation Mistaken for Malignancy: Tuberculosis Identified Post Orchiectomy.

We describe the case of a 41-year-old Hispanic male, inconsistently adherent to visits and workup due to socioeconomic challenges, who presented with a right testicular mass. Because of the overriding concern that this was malignant, he underwent a right orchiectomy. Pathology revealed granulomatous disease with no evidence of malignancy. No specific diagnosis was made histologically or microbiologically on primary laboratory investigation. Six months later, he developed swelling of the left testicle and was subsequently seen in consultation at the Infectious Disease Clinic Kern Medical. An extensive evaluation for granulomatous inflammation was undertaken without a positive result. A clinical diagnosis of tuberculous epididymal orchitis was made and the patient was initiated on standard 4-drug antituberculous therapy. There was a gradual resolution of pain and swelling. After 6 months of therapy, there was no evidence of residual disease. The patient remains asymptomatic after 8 months of post-therapy follow-up.

Distribution and Diffusion of Macromolecule Delivery to the Brain via Focused Ultrasound using Magnetic Resonance and Multispectral Fluorescence Imaging.

Focused ultrasound (FUS), in combination with microbubble contrast agents, can be used to transiently open the blood-brain barrier (BBB) to allow intravascular agents to cross into the brain. Often, FUS is carried out in conjunction with magnetic resonance imaging (MRI) to evaluate BBB opening to gadolinium-based MRI contrast agents. Although MRI allows direct visualization of the distribution of gadolinium-based contrast agents in the brain parenchyma, it does not allow measurements of the distribution of other molecules crossing the BBB. Therapeutic molecules (e.g., monoclonal antibodies) are much different in size than MRI contrast agents and have been found to have different distributions in the brain after FUS-mediated BBB opening. In the work described here, we combined in vivo MRI and ex vivo multispectral fluorescence imaging to compare the distributions of MRI contrast and dextran molecules of different molecular weights (3, 70 and 500 kDa) after FUS-mediated BBB opening through a range of ultrasound pressures (0.18-0.46 MPa) in laboratory mice. The volume of brain exposed was calculated from the MRI and fluorescence images and was significantly dependent on both molecular weight and ultrasound pressure. Diffusion coefficients of the different-molecular-weight dextran molecules in the brain parenchyma were also calculated from the fluorescence images and were negatively correlated with the molecular weight of the dextran molecules. The results of this work build on a body of knowledge that is critically important for the FUS technique to be used in clinical delivery of therapeutics to the brain.

Single-cell multiomic profiling of human lungs reveals cell-type-specific and age-dynamic control of SARS-CoV2 host genes.

Respiratory failure associated with COVID-19 has placed focus on the lungs. Here, we present single-nucleus accessible chromatin profiles of 90,980 nuclei and matched single-nucleus transcriptomes of 46,500 nuclei in non-diseased lungs from donors of ~30 weeks gestation,~3 years and ~30 years. We mapped candidate cis-regulatory elements (cCREs) and linked them to putative target genes. We identified distal cCREs with age-increased activity linked to SARS-CoV-2 host entry gene TMPRSS2 in alveolar type 2 cells, which had immune regulatory signatures and harbored variants associated with respiratory traits. At the 3p21.31 COVID-19 risk locus, a candidate variant overlapped a distal cCRE linked to SLC6A20, a gene expressed in alveolar cells and with known functional association with the SARS-CoV-2 receptor ACE2. Our findings provide insight into regulatory logic underlying genes implicated in COVID-19 in individual lung cell types across age. More broadly, these datasets will facilitate interpretation of risk loci for lung diseases.

Concomitant Central Nervous System Toxoplasmosis and Seronegative Disseminated Coccidioidomycosis in a Newly Diagnosed Acquired Immune Deficiency Syndrome Patient.

Opportunistic infections (OIs) are a significant cause of morbidity and mortality in immunosuppressed patients and may be due to bacteria, virus, protozoa, or fungi. Toxoplasmosis is a common cause of central nervous system infection in human immunodeficiency virus (HIV) patients. Coccidioidomycosis is a relatively common fungal infection that may lead to disseminated disease and fungemia in immune-compromised hosts living in endemic regions. This single-patient case report documents the presentation, diagnosis, management, and outcome of concomitant central nervous system toxoplasmosis and diffuse miliary pneumonia with fungemia due to disseminated seronegative Coccidioides immitis in a 33-year-old male patient recently diagnosed with chronic advanced HIV. Impaired cellular immune function, such as defects in the IL-12/IFN-γ pathway or T-helper IL-17-mediated response, is associated with increased severity of coccidioidomycosis. Fungemia and acute respiratory distress syndrome are both associated with very high mortality in coccidioidomycosis. In HIV hosts, negative Coccidioides serology can be seen in up to 25% of cases and therefore other diagnostic modalities should be initiated promptly and simultaneously. This case demonstrates simultaneous OI in the setting of advanced acquired immune deficiency syndrome and emphasizes the need for early diagnosis of HIV and OI in order to ensure prompt initiation of antiretroviral therapy, prophylactic, and therapeutic medications.

Xylanase attachment to the cell wall of the hyperthermophilic bacterium Thermotoga maritima.

The cellular localization and processing of the endo-xylanases (1,4-beta-D-xylan-xylanohydrolase; EC 3.2.1.8) of the hyperthermophile Thermotoga maritima were investigated, in particular with respect to the unusual outer membrane ("toga") of this gram-negative bacterium. XynB (40 kDa) was detected in the periplasmic fraction of T. maritima cells and in the culture supernatant. XynA (120 kDa) was partially released to the surrounding medium, but most XynA remained cell associated. Immunogold labeling of thin sections revealed that cell-bound XynA was localized mainly in the outer membranes of T. maritima cells. Amino-terminal sequencing of purified membrane-bound XynA revealed processing of the signal peptide after the eighth residue, thereby leaving the hydrophobic core of the signal peptide attached to the enzyme. This mode of processing is reminiscent of type IV prepilin signal peptide cleavage. Removal of the entire XynA signal peptide was necessary for release from the cell because enzyme purified from the culture supernatant lacked 44 residues at the N terminus, including the hydrophobic part of the signal peptide. We conclude that toga association of XynA is mediated by residues 9 to 44 of the signal peptide. The biochemical and electron microscopic localization studies together with the amino-terminal processing data indicate that XynA is held at the cell surface of T. maritima via a hydrophobic peptide anchor, which is highly unusual for an outer membrane protein.

Semi-automated quantification and neuroanatomical mapping of heterogeneous cell populations.

BACKGROUND: Our group studies the interactions between cells of the brain and the neurotropic parasite Toxoplasma gondii. Using an in vivo system that allows us to permanently mark and identify brain cells injected with Toxoplasma protein, we have identified that Toxoplasma-injected neurons (TINs) are heterogeneously distributed throughout the brain. Unfortunately, standard methods to quantify and map heterogeneous cell populations onto a reference brain atlas are time consuming and prone to user bias. NEW METHOD: We developed a novel MATLAB-based semi-automated quantification and mapping program to allow the rapid and consistent mapping of heterogeneously distributed cells on to the Allen Institute Mouse Brain Atlas. The system uses two-threshold background subtraction to identify and quantify cells of interest. RESULTS: We demonstrate that we reliably quantify and neuroanatomically localize TINs with low intra- or inter-observer variability. In a follow up experiment, we show that specific regions of the mouse brain are enriched with TINs. COMPARISON WITH EXISTING METHODS: The procedure we use takes advantage of simple immunohistochemistry labeling techniques, use of a standard microscope with a motorized stage, and low cost computing that can be readily obtained at a research institute. To our knowledge there is no other program that uses such readily available techniques and equipment for mapping heterogeneous populations of cells across the whole mouse brain. CONCLUSION: The quantification method described here allows reliable visualization, quantification, and mapping of heterogeneous cell populations in immunolabeled sections across whole mouse brains.

Structure-functional analysis of the Dictyoglomus cell envelope.

Several closely related strains of the thermophilic bacterium Dictyoglomus have been isolated from various hot springs on the Philippine archipelago. These strains as well as Dictyoglomus thermophilum H-6-12 were analyzed in view of the structure-functional relationships of the cell envelopes. All envelopes of Dictyoglomus strains show several peculiar features that are apparently either unique for the genus or common for other phylogenetically related Thermotogales. The filamentous cells develop pili at the cell poles, guided by large columnar protein assemblies that traverse the periplasm. Filamentous protein complexes span the periplasmic space at the longitudinal sides of the cell. By the end of the exponential growth phase, Dictyoglomus strains form multicellular aggregates ("rotund bodies") inside a compartment surrounded by a single, continuous outer envelope. The formation of these rotund bodies which are also found in some other deeply branching thermophilic phyla (Thermotoga, Thermus) was studied in detail. The transition between unicellular and multicellular lifestyle can be explained by the partial detachment of a protoplast from the outer envelope during cell division. When the outer envelope is partially detached from the protoplast, mechanical forces generated by protoplast elongation may drive cell rearrangement of daughter cells inside the compartment. During the following rounds of cell division, the overall shape of the compartment changes from spindle-like to globular geometry. Analysis of subcellular fractions of Dictyoglomus cells shows that glucan hydrolases are associated with the compartment. This feature is discussed in view of the multicellular life style of Dictyoglomus.