Dr. Steffes, a Wisconsin native, completed medical school and pediatric residency at the Medical College of Wisconsin. She then moved to the Bay Area and completed her clinical fellowship in pediatric pulmonary medicine at Stanford University in 2020. Additionally, Dr. Steffes received further post-doctoral training in the laboratories of Dr. Maya Kumar and Dr. David Cornfield, studying the cellular and molecular mechanism driving pulmonary vascular disease. In addition to her role as an Instructor in Pediatrics in the division of Pulmonary Medicine, Dr. Steffes is also completing an advanced clinical fellowship in Pulmonary Hypertension at Lucile Packard Children’s Hospital Stanford. Her clinical work consists of caring for patients with pediatric pulmonary and pulmonary vascular diseases such as pulmonary hypertension, bronchopulmonary dysplasia, interstitial lung disease, respiratory failure, chronic cough and asthma. Her research is focused on the vascular changes seen in pulmonary hypertension, more specifically understanding the cellular characteristics of occlusive neointimal lesions, the abnormal cells that block pulmonary blood flow in pulmonary hypertension. In her most recent work, Dr. Steffes identified a subset of healthy vascular smooth muscle cells that are the cell of origin for the pathologic neointimal cells and a specific signaling pathway, that when blocked, inhibits the formation of neointimal lesions.
Dr. Steffes is currently employing advanced single cell sequencing technologies to further understand neointimal cells with the ultimate goal identifying new therapies for pulmonary hypertension, a fatal disease with no known cure.
- Pediatric Pulmonary
Board Certification, American Board of Pediatrics, Pediatric Pulmonary Medicine (2020)
Fellowship, Stanford University, Pediatric Pulmonary Medicine (2020)
Board Certification: American Board of Pediatrics, Pediatrics (2017)
Residency, Medical College of Wisconsin, Pediatrics (2017)
Medical Education, Medical College of Wisconsin, Medicine (2014)
- von Willebrand Factor Is Produced Exclusively by Endothelium, Not Neointima, in Occlusive Vascular Lesions in Both Pulmonary Hypertension and Atherosclerosis. Circulation 2022; 146 (5): 429-431
The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans.
Science (New York, N.Y.)
2022; 376 (6594): eabl4896
Molecular characterization of cell types using single-cell transcriptome sequencing is revolutionizing cell biology and enabling new insights into the physiology of human organs. We created a human reference atlas comprising nearly 500,000 cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression. Using multiple tissues from a single donor enabled identification of the clonal distribution of T cells between tissues, identification of the tissue-specific mutation rate in B cells, and analysis of the cell cycle state and proliferative potential of shared cell types across tissues. Cell type-specific RNA splicing was discovered and analyzed across tissues within an individual.
View details for DOI 10.1126/science.abl4896
View details for PubMedID 35549404
- Publisher Correction: Cell types of origin of the cell-free transcriptome. Nature biotechnology 2022
Cell types of origin of the cell-free transcriptome.
Cell-free RNA from liquid biopsies can be analyzed to determine disease tissue of origin. We extend this concept to identify cell types of origin using the Tabula Sapiens transcriptomic cell atlas as well as individual tissue transcriptomic cell atlases in combination with the Human Protein Atlas RNA consensus dataset. We define cell type signature scores, which allow the inference of cell types that contribute to cell-free RNA for a variety of diseases.
View details for DOI 10.1038/s41587-021-01188-9
View details for PubMedID 35132263
- Upfront Combination Therapy: Growing the Case to Get Ahead of Pediatric Pulmonary Arterial Hypertension. Annals of the American Thoracic Society 1800; 19 (2): 163-165
- Chronic Daily House Dust Mite Exposure in Mice is an Effective Model to Quantify the Effect of Pharmacologic Agents on Discrete Stages of Artery Remodeling in Pulmonary Hypertension BIO-PROTOCOL 2022; 12 (01)
Chronic Daily House Dust Mite Exposure in Mice is an Effective Model to Quantify the Effect of Pharmacologic Agents on Discrete Stages of Artery Remodeling in Pulmonary Hypertension.
2022; 12 (1): e4273
Pulmonary hypertension (PH) is a heterogenous and incurable disease marked by varying degrees of pulmonary vascular remodeling. This vascular remodeling, which includes thickening of the smooth muscle layer (an early finding) and formation of occlusive neointimal lesions (a late finding) in the pulmonary arteries, is a major driver of morbidity and mortality in PH. Available PH therapies consist of vasodilators that do not specifically target lesion formation or expansion and neither prevent progression nor reverse disease. This paucity of curative treatments highlights the need for new drug discovery targeting crucial steps of artery remodeling in PH. The cell dynamics and molecular signals driving neointimal lesion formation have been difficult to elucidate as classic mouse models of PH do not develop neointima. Here, we detail the methods to generate a robust and non-genetic mouse model of PH with medial thickening and neointimal lesion formation in the pulmonary arteries, through chronic exposure to an inflammatory stimulus-house dust mite (HDM). This model rapidly generates human-like pulmonary arterial lesions following a reproducible time course, allowing scrutiny of the cellular and molecular mechanisms controlling each stage of artery remodeling. Further, we outline optimal tissue handling, sectioning, and staining methodologies for detailed quantitative analysis of artery medial thickening and neointimal lesion formation and expansion. Finally, we present a method for staged pharmacologic intervention to identify molecules and pathways required at each step of the pulmonary arterial remodeling process. The advantages of this mouse model of PH over currently available animal models are five-fold. (i) It allows the use of the full range of genetic and single cell tools available in mice to manipulate and study the process of vascular remodeling seen in human disease, including the formation of neointimal lesions in a controlled and cell specific manner. (ii) The vascular lesions develop in a stereotyped manner with predictable timing, allowing for pharmacologic manipulation at discrete stages of vessel remodeling. (iii) It is rapid, with development of PH and vascular remodeling in a timeframe of two to eight weeks. (iv) It uses simple techniques and requires neither surgery, unusual equipment, or extensive personnel training. (v) The staining and quantitation methodologies we present are a significant improvement over those currently in use in the field. We hope that dissemination of this model and the associated detailed methods will speed up the development of novel and more effective PH therapeutics. Graphic abstract: Chronic perivascular inflammation induces medial thickening and neointima formation in pulmonary arteries, following a stereotyped time course, and allowing staged pharmacologic intervention during specific remodeling events, as well as quantitative assessment of vascular changes.
View details for DOI 10.21769/BioProtoc.4273
View details for PubMedID 35118166
View details for PubMedCentralID PMC8769763
- RNA splicing programs define tissue compartments and cell types at single-cell resolution ELIFE 2021; 10
Coronavirus disease 2019 respiratory disease in children: clinical presentation and pathophysiology.
Current opinion in pediatrics
2021; 33 (3): 302–10
PURPOSE OF REVIEW: Pediatric coronavirus disease 2019 (COVID-19) respiratory disease is a distinct entity from adult illness, most notable in its milder phenotype. This review summarizes the current knowledge of the clinical patterns, cellular pathophysiology, and epidemiology of COVID-19 respiratory disease in children with specific attention toward factors that account for the maturation-related differences in disease severity.RECENT FINDINGS: Over the past 14 months, knowledge of the clinical presentation and pathophysiology of COVID-19 pneumonia has rapidly expanded. The decreased disease severity of COVID-19 pneumonia in children was an early observation. Differences in the efficiency of viral cell entry and timing of immune recognition and response between children and adults remain at the center of ongoing research.SUMMARY: The clinical spectrum of COVID-19 respiratory disease in children is well defined. The age-related differences protecting children from severe disease and death remain incompletely understood.
View details for DOI 10.1097/MOP.0000000000001013
View details for PubMedID 33938476
- Three Infants with Pathogenic Variants in the ABCA3 Gene: Presentation, Treatment and Clinical Course. The Journal of pediatrics 2020
A Notch3-Marked Subpopulation of Vascular Smooth Muscle Cells is the Cell of Origin for Occlusive Pulmonary Vascular Lesions.
Background: Pulmonary arterial hypertension (PAH) is a fatal disease characterized by profound vascular remodeling in which pulmonary arteries narrow due to medial thickening and occlusion by neointimal lesions, resulting in elevated pulmonary vascular resistance and right heart failure. Therapies targeting the neointima would represent a significant advance in PAH treatment, however our understanding of the cellular events driving neointima formation, and the molecular pathways that control them, remains limited. Methods: We comprehensively map the stepwise remodeling of pulmonary arteries in a robust, chronic inflammatory mouse model of pulmonary hypertension. This model demonstrates pathologic features of the human disease, including increased right ventricular pressures, medial thickening, neointimal lesion formation, elastin breakdown, increased anastomosis within the bronchial circulation, and perivascular inflammation. Using genetic lineage tracing, clonal analysis, multiplexed in situ hybridization, immunostaining, deep confocal imaging and staged pharmacologic inhibition we define the cell behaviors underlying each stage of vascular remodeling and identify a pathway required for neointima formation. Results: Neointima arises from smooth muscle cells (SMCs) and not endothelium. Medial SMCs proliferate broadly to thicken the media, after which a small number of SMCs are selected to establish the neointima. These neointimal founder cells subsequently undergoing massive clonal expansion to form occlusive neointimal lesions. The normal pulmonary artery SMC population is heterogeneous and we identify a Notch3-marked minority subset of SMCs as the major neointimal cell of origin. Notch signaling is specifically required for the selection of neointimal founder cells, and Notch inhibition significantly improves pulmonary artery pressure in animals with pulmonary hypertension. Conclusions: This work describes the first nongenetically driven murine model of PH that generates robust and diffuse occlusive neointimal lesions across the pulmonary vascular bed and does so in a stereotyped timeframe. We uncover distinct cellular and molecular mechanisms underlying medial thickening and neointima formation and highlight novel transcriptional, behavioral and pathogenic heterogeneity within pulmonary artery SMCs. In this model, inflammation is sufficient to generate characteristic vascular pathologies and physiologic measures of human PAH. We hope that identifying the molecular cues regulating each stage of vascular remodeling will open new avenues for therapeutic advancements in the treatment of PAH.
View details for DOI 10.1161/CIRCULATIONAHA.120.045750
View details for PubMedID 32794408