Publications by authors named "Madhu Gowda"

12 Publications

  • Page 1 of 1

Selective Bacterial Colonization of the Murine Larynx in a Gnotobiotic Model.

Front Microbiol 2020 4;11:594617. Epub 2020 Nov 4.

Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States.

The larynx is a mucosal organ situated between the respiratory and gastrointestinal tracts. Little is known about microbial contributions to laryngeal epithelial health and pathogenesis. Developing a gnotobiotic laryngeal model will introduce new avenues for targeted explorations of microbes in laryngeal mucosal biology, allowing for enhanced understanding of host-microbe interaction in the upper airway. In this study, we first assessed the potential of using gut microbiota as a source to establish laryngeal microbiota in germ-free mice. Results demonstrated the selective nature of the upper airway and provided evidence that gut bacteria can assemble into communities that resemble the commensal resident bacteria occurring in the larynx of conventionally-raised animals phylogenetically and functionally. Then, we confirmed the reproducibility of laryngeal colonization through comparison of laryngeal microbiota in the larynx along with neighboring regions (base of tongue, esophagus, and trachea) between conventionally-raised and germ-free mice that conventionalized with cecal microbiota. Despite taxonomic differences, the established laryngeal microbiota from cecal content exhibited similarity to commensal resident microbiota in diversity within/between communities and predicted metagenomic functions. Our data also suggests little difference in bacterial distribution across the larynx and its surrounding regions and that cell motility and the ability to degrade xenobiotics is critical for bacteria colonizing upper airway. Successful colonization of laryngeal and oropharyngeal regions with gut microbiota in our study will greatly facilitate the investigation of potential localized inflammatory responses within host tissues that contribute to the disorders of essential laryngeal functions. Utilizing said gnotobiotic model to conduct future studies will allow for novel insights into direct microbial contributions to laryngeal epithelial health and pathogenesis.
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http://dx.doi.org/10.3389/fmicb.2020.594617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7676279PMC
November 2020

Case 3: Left Eye Swelling in a 9-year-old Girl.

Pediatr Rev 2019 Aug;40(8):428-430

Division of Pediatric Hospital Medicine and.

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http://dx.doi.org/10.1542/pir.2017-0219DOI Listing
August 2019

Laryngotracheal Microbiota in Adult Laryngotracheal Stenosis.

mSphere 2019 05 1;4(3). Epub 2019 May 1.

Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin, USA

Laryngotracheal stenosis is an obstructive respiratory disease that leads to voicing difficulties and dyspnea with potential life-threatening consequences. The majority of incidences are due to iatrogenic etiology from endotracheal tube intubation; however, airway scarring also has idiopathic causes. While recent evidence suggests a microbial contribution to mucosal inflammation, the microbiota associated with different types of stenosis has not been characterized. High-throughput sequencing of the V4 region of the16S rRNA gene was performed to characterize the microbial communities of 61 swab samples from 17 iatrogenic and 10 adult idiopathic stenosis patients. Nonscar swabs from stenosis patients were internal controls, and eight swabs from four patients without stenosis represented external controls. Significant differences in diversity were observed between scar and nonscar samples and among sample sites, with decreased diversity detected in scar samples and the glottis region. Permutational analysis of variance (PERMANOVA) results revealed significant differences in community composition for scar versus nonscar samples, etiology type, sample site, groups (iatrogenic, idiopathic, and internal and external controls), and individual patients. Pairwise Spearman's correlation revealed a strong inverse correlation between and among all samples. Finally, bacteria in the family were found to be distinctly associated with idiopathic stenosis samples in comparison with external controls. Our findings suggest that specific microbiota and community shifts are present with laryngotracheal stenosis in adults, with members of the family , including the known pathogens and , identified in idiopathic scar. Further work is warranted to elucidate the contributing role of bacteria on the pathogenesis of laryngotracheal stenosis. The laryngotracheal region resides at the intersection between the heavily studied nasal cavity and lungs; however, examination of the microbiome in chronic inflammatory conditions of the subglottis and trachea remains scarce. To date, studies have focused on the microbiota of the vocal folds, or the glottis, for laryngeal carcinoma, as well as healthy larynges, benign vocal fold lesions, and larynges exposed to smoking and refluxate. In this study, we seek to examine the structure and composition of the microbial community in adult laryngotracheal stenosis of various etiologies. Due to the heterogeneity among the underlying pathogenesis mechanisms and clinical outcomes seen in laryngotracheal stenosis disease, we hypothesized that different microbial profiles will be detected among various stenosis etiology types. Understanding differences in the microbiota for subglottic stenosis subtypes may shed light upon etiology-specific biomarker identification and offer novel insights into management approaches for this debilitating disease.
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http://dx.doi.org/10.1128/mSphereDirect.00211-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6495342PMC
May 2019

Change Theory Contributes to Choosing Wisely for Immune Thrombocytopenia.

Hosp Pediatr 2019 03;9(3):156-161

Division of Hematology, Oncology, and Stem Cell Transplantation, School of Medicine, Virginia Commonwealth University and Massey Cancer Center, Richmond, Virginia.

Objectives: Despite 2011 guidelines in which it is suggested that treatment of acute immune thrombocytopenia purpura (aITP) is not needed for patients without significant bleeding, only 14% of children treated for aITP have bleeding symptoms. Our aim was to decrease the percentage of children with first-episode aITP who were unnecessarily treated by 50% within 12 months of guideline implementation.

Methods: An intervention was designed by using the precaution-adoption-process model. A standard-of-practice meeting was organized and focused on clinician readiness for change. After education on current evidence and common cognitive errors, consensus clinical guidelines were created. After implementation, an article in a statewide professional newsletter was published to educate community providers. Unnecessary treatment (UT) was defined as treatment of any patient who only had bruising and/or self-resolving nose bleeds. Statistical process control charts were used to track progress, midline shifts were determined by Nelson's rules, and hospital costs were derived from administrative billing data.

Results: One hundred children with aITP were seen from January 2013 to September 2018. UT decreased from 70% to a sustained rate of <30% ( = .008), including a mean of 7% over the past 12 months. The admission rate decreased from 100% to 52% ( = .013), and the total percentage of patients treated decreased from 100% to 48% ( = .016), with both numbers continuing to decline. No adverse bleeding events occurred. An estimated 12 admissions, 4 readmissions, and 5 adverse events were avoided annually.

Conclusions: We demonstrated successful improvement in UT of aITP through an educational intervention informed by the precaution-adoption-process model change theory.
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http://dx.doi.org/10.1542/hpeds.2018-0231DOI Listing
March 2019

Outcomes of Measurable Residual Disease in Pediatric Acute Myeloid Leukemia before and after Hematopoietic Stem Cell Transplant: Validation of Difference from Normal Flow Cytometry with Chimerism Studies and Wilms Tumor 1 Gene Expression.

Biol Blood Marrow Transplant 2018 10 19;24(10):2040-2046. Epub 2018 Jun 19.

Division of Hematology, Oncology, and Blood and Marrow Transplantation, Children's Hospital Los Angeles, USC Keck School of Medicine, Los Angeles, CA, USA.

We enrolled 150 patients in a prospective multicenter study of children with acute myeloid leukemia undergoing hematopoietic stem cell transplantation (HSCT) to compare the detection of measurable residual disease (MRD) by a "difference from normal" flow cytometry (ΔN) approach with assessment of Wilms tumor 1 (WT1) gene expression without access to the diagnostic specimen. Prospective analysis of the specimens using this approach showed that 23% of patients screened for HSCT had detectable residual disease by ΔN (.04% to 53%). Of those patients who proceeded to transplant as being in morphologic remission, 10 had detectable disease (.04% to 14%) by ΔN. The disease-free survival of this group was 10% (0 to 35%) compared with 55% (46% to 64%, P < .001) for those without disease. The ΔN assay was validated using the post-HSCT specimen by sorting abnormal or suspicious cells to confirm recipient or donor origin by chimerism studies. All 15 patients who had confirmation of tumor detection relapsed, whereas the 2 patients with suspicious phenotype cells lacking this confirmation did not. The phenotype of the relapse specimen was then used retrospectively to assess the pre-HSCT specimen, allowing identification of additional samples with low levels of MRD involvement that were previously undetected. Quantitative assessment of WT1 gene expression was not predictive of relapse or other outcomes in either pre- or post-transplant specimens. MRD detected by ΔN was highly specific, but did not identify most relapsing patients. The application of the assay was limited by poor quality among one-third of the specimens and lack of a diagnostic phenotype for comparison.
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http://dx.doi.org/10.1016/j.bbmt.2018.06.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6239928PMC
October 2018

Targeted inhibition of histone H3K27 demethylation is effective in high-risk neuroblastoma.

Sci Transl Med 2018 05;10(441)

Virginia Commonwealth University Philips Institute, School of Dentistry and Massey Cancer Center, Richmond, VA 23298, USA.

High-risk neuroblastoma is often distinguished by amplification of and loss of differentiation potential. We performed high-throughput drug screening of epigenetic-targeted therapies across a large and diverse tumor cell line panel and uncovered the hypersensitivity of neuroblastoma cells to GSK-J4, a small-molecule dual inhibitor of lysine 27 of histone 3 (H3K27) demethylases ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX), and histone demethylase Jumonji D3 (JMJD3). Mechanistically, GSK-J4 induced neuroblastoma differentiation and endoplasmic reticulum (ER) stress, with accompanying up-regulation of p53 up-regulated modulator of apoptosis (PUMA) and induction of cell death. Retinoic acid (RA)-resistant neuroblastoma cells were sensitive to GSK-J4. In addition, GSK-J4 was effective at blocking the growth of chemorefractory and patient-derived xenograft models of high-risk neuroblastoma in vivo. Furthermore, GSK-J4 and RA combination increased differentiation and ER stress over GSK-J4 effects and limited the growth of neuroblastomas resistant to either drug alone. In -amplified neuroblastoma, PUMA induction by GSK-J4 sensitized tumors to the B cell lymphoma 2 (BCL-2) inhibitor venetoclax, demonstrating that epigenetic-targeted therapies and BCL-2 homology domain 3 mimetics can be rationally combined to treat this high-risk subset of neuroblastoma. Therefore, H3K27 demethylation inhibition is a promising therapeutic target to treat high-risk neuroblastoma, and H3K27 demethylation can be part of rational combination therapies to induce robust antineuroblastoma activity.
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http://dx.doi.org/10.1126/scitranslmed.aao4680DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6200133PMC
May 2018

Insights Into the Role of Collagen in Vocal Fold Health and Disease.

J Voice 2017 Sep 27;31(5):520-527. Epub 2017 Mar 27.

Department of Surgery, Voice and Swallow Clinics, Division of Otolaryngology-Head & Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. Electronic address:

As one of the key fibrous proteins in the extracellular matrix, collagen plays a significant role in the structural and biomechanical characteristics of the vocal fold. Anchored fibrils of collagen create secure structural regions within the vocal folds and are strong enough to sustain vibratory impact and stretch during phonation. This contributes tensile strength, density, and organization to the vocal folds and influences health and pathogenesis. This review offers a comprehensive summary for a current understanding of collagen within normal vocal fold tissues throughout the life span as well as vocal pathology and wound repair. Further, collagen's molecular structure and biosynthesis are discussed. Finally, collagen alterations in tissue injury and repair and the incorporation of collagen-based biomaterials as a method of treating voice disorders are reviewed.
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http://dx.doi.org/10.1016/j.jvoice.2017.01.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5583023PMC
September 2017

Exploitation of the Apoptosis-Primed State of MYCN-Amplified Neuroblastoma to Develop a Potent and Specific Targeted Therapy Combination.

Cancer Cell 2016 Feb;29(2):159-72

Philips Institute for Oral Health Research, VCU School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Perkinson Building, Richmond, VA 23298, USA. Electronic address:

Fewer than half of children with high-risk neuroblastoma survive. Many of these tumors harbor high-level amplification of MYCN, which correlates with poor disease outcome. Using data from our large drug screen we predicted, and subsequently demonstrated, that MYCN-amplified neuroblastomas are sensitive to the BCL-2 inhibitor ABT-199. This sensitivity occurs in part through low anti-apoptotic BCL-xL expression, high pro-apoptotic NOXA expression, and paradoxical, MYCN-driven upregulation of NOXA. Screening for enhancers of ABT-199 sensitivity in MYCN-amplified neuroblastomas, we demonstrate that the Aurora Kinase A inhibitor MLN8237 combines with ABT-199 to induce widespread apoptosis. In diverse models of MYCN-amplified neuroblastoma, including a patient-derived xenograft model, this combination uniformly induced tumor shrinkage, and in multiple instances led to complete tumor regression.
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http://dx.doi.org/10.1016/j.ccell.2016.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4749542PMC
February 2016

HLA-DR expression on myeloid cells is a potential prognostic factor in patients with high-risk neuroblastoma.

Oncoimmunology 2013 Oct 10;2(10):e26616. Epub 2013 Oct 10.

Department of Microbiology and Immunology; Virginia Commonwealth University; Massey Cancer Center; Richmond, VA USA.

The adaptive immune system has been reported to play a dual role in many cancers, on one hand inhibiting tumor growth and, on the other hand, promoting disease progression, escape from cancer immunosurveillance and relapse. We have previously reported that the suppression of the adaptive immune response associated with high levels of myeloid-derived suppressor cells (MDSC) was evident in patients with low-risk neuroblastoma. Here, we report the results of a pilot study demonstrating that the amounts of HLA-DR-positive or negative myeloid cells in the peripheral blood might predict disease outcome among individuals affected by high-risk neuroblastoma.
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http://dx.doi.org/10.4161/onci.26616DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3857328PMC
October 2013

Distinct signatures of the immune responses in low risk versus high risk neuroblastoma.

J Transl Med 2011 Oct 6;9:170. Epub 2011 Oct 6.

Department of Pediatrics, Children's Hospital of Richmond, Richmond, VA, USA.

Background: Over 90% of low risk (LR) neuroblastoma patients survive whereas less than 30% of high risk (HR) patients are long term survivors. Age (children younger than 18 months old) is associated with LR disease. Considering that adaptive immune system is well developed in older children, and that T cells were shown to be involved in tumor escape and progression of cancers, we sought to determine whether HR patients may tend to show a signature of adaptive immune responses compared to LR patients who tend to have diminished T-cell responses but an intact innate immune response.

Methods: We performed microarray analysis of RNA extracted from the tumor specimens of HR and LR patients. Flow cytometry was performed to determine the cellular constituents in the blood while multiplex cytokine array was used to detect the cytokine profile in patients' sera. A HR tumor cell line, SK-N-SH, was also used for detecting the response to IL-1β, a cytokines which is involved in the innate immune responses.

Results: Distinct patterns of gene expression were detected in HR and LR patients indicating an active T-cell response and a diminished adaptive immune response, respectively. A diminished adaptive immune response in LR patients was evident by higher levels of IL-10 in the sera. In addition, HR patients had lower levels of circulating myeloid derived suppressor cells (MDSC) compared with a control LR patient. LR patients showed slightly higher levels of cytokines of the innate immune responses. Treatment of the HR tumor line with IL-1β induced expression of cytokines of the innate immune responses.

Conclusions: This data suggests that adaptive immune responses may play an important role in the progression of HR disease whereas innate immune responses may be active in LR patients.
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http://dx.doi.org/10.1186/1479-5876-9-170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3195752PMC
October 2011

CD4+ T cells inhibit the neu-specific CD8+ T-cell exhaustion during the priming phase of immune responses against breast cancer.

Breast Cancer Res Treat 2011 Apr 18;126(2):385-94. Epub 2010 May 18.

Department of Microbiology & Immunology, Virginia Commonwealth University Massey Cancer Center, Box 980035, Richmond, VA 23298, USA.

Studies conducted in animal model of infectious diseases or H-Y antigen model suggest a crucial role for CD4+ T cells in providing help for CD8+ T-cell memory responses. This concept suggests that inclusion of T helper epitopes in vaccine formulation will result in improved CD8+ T-cell responses. Although this concept has been applied to cancer vaccine design, the role of CD4+ T cells in the memory differentiation of CD8+ T cells and retention of their anti-tumor function have never been tested in breast cancer model. Using the FVB mouse model of neu-positive breast carcinoma we report for the first time that helpless T cells showed cytostatic or tumor inhibitory effects during primary tumor challenge whereas, helped T cells showed cytotoxic effects and resulted in complete tumor rejection. Such differential effects, in vivo, were associated with higher frequency of CD8+PD-L1+ and CD8+PD-1+ T cells in animals harboring helpless T cells as well as higher titer of IL-2 in the sera of animals harboring helped T cells. However, depletion of CD4+ T cells did not alter the ability of neu-specific CD8+ T cells to differentiate into memory cells and to retain their effector function against the tumor during recall challenge. These results suggest the inhibitory role of CD4+ T cells on CD8+ T-cell exhaustion without substantial effects on the differentiation of memory T cells during priming phase of the immune responses against breast cancer.
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http://dx.doi.org/10.1007/s10549-010-0942-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086038PMC
April 2011

Human T cells express CD25 and Foxp3 upon activation and exhibit effector/memory phenotypes without any regulatory/suppressor function.

J Transl Med 2009 Oct 22;7:89. Epub 2009 Oct 22.

Department of Microbiology & Immunology, Virginia Commonwealth University Massey Cancer Center, Richmond, USA.

Background: Foxp3 has been suggested to be a standard marker for murine Tregs whereas its role as marker for human Tregs is controversial. While some reports have shown that human Foxp3+ T cells had no regulatory function others have shown their role in the inhibition of T cell proliferation.

Methods: T cell activation was performed by means of brayostatin-1/ionomycin (B/I), mixed lymphocyte reaction (MLR), and CD3/CD28 activation. T cell proliferation was performed using BrdU and CFSE staining. Flow cytometry was performed to determine Foxp3 expression, cell proliferation, viabilities and phenotype analyses of T cells.

Results: Both CD4+ and CD8+ T cells expressed Foxp3 upon activation in vitro. Expression of Foxp3 remained more stable in CD4+CD25+ T cells compared to that in CD8+CD25+ T cells. The CD4+CD25+Foxp3+ T cells expressed CD44 and CD62L, showing their effector and memory phenotypes. Both FoxP3- responder T cells and CD4+FoxP3+ T cells underwent proliferation upon CD3/CD28 activation.

Conclusion: Expression of Foxp3 does not necessarily convey regulatory function in human CD4+CD25+ T cells. Increased FoxP3 on CD44+ effector and CD44+CD62L+ memory T cells upon stimulation suggest the activation-induced regulation of FoxP3 expression.
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http://dx.doi.org/10.1186/1479-5876-7-89DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2770477PMC
October 2009