Rutgers Institute for Translational Medicine and Science
Child Health Institute of New Jersey
Rutgers, The State University of New Jersey
89 French Street, Suite 4275
New Brunswick, NJ 08901

(732) 235-9132
sa1510@rbhs.rutgers.edu

Education: Ph.D., Brown University, Providence, RI
B.A. University of Virginia, Charlottesville, VA

Postdoctoral Fellowship: Harvard University, Boston, MA

Dr. Steven S. An, Ph.D. is Professor of Pharmacology and Director of Bioengineering at the RITMS.  Dr. An is an Elected Fellow of the American Thoracic Society (ATS) and has served the Society and its over 77,000 membership as Member of the International Conference Committee and Chair of the Respiratory Structure and Function (RSF) Program Committee. His service to RSF Assembly also includes serving as member of its Planning Committee and its Nominating Committee. He has specific expertise in G protein-coupled receptor (GPCR) signaling and excitation-contraction coupling mechanisms of airway smooth muscle shortening in the context of obstructive lung diseases.

Research Focus:

We aim to understand the mechanobiology across the length scale–how cells and tissues grow, contract, move, invade, and remodel. Understanding the underlying mechanisms of these fundamental biological processes can provide new approaches to tissue regeneration and therapy for diseases such as asthma and cancer.

We develop new technologies to modulate and visualize the physical forces in living cells. The laboratory of Dr. Steven An has the unique capability to map the cellular stress using Fourier transform traction microscopy (FTTM), to probe the material properties of living cytoskeleton using optical magnetic twisting cytometry (OMTC), and to quantitate the molecular-level remodeling of internal structures using spontaneous nanoscale tracer motions (SNTM). These live-cell micromechanical methods are readily applicable to a wide variety of cell types and have broad research applications that are at the interface between engineering, cell biology and medicine.

Recently, we have developed a new micro-physiological system that reconstitutes 3D co-cultures of human airway smooth muscle cells with clinically-relevant human airway epithelial cells that are fully differentiated in an air-liquid interface (Nat. Biomed. Eng. 2019). This “bronchi-chip” is fully equipped with OMTC enabling the interrogation, in real-time, of the interplay between chemical and mechanical cues, and the heterotypic cell responses, driving asthma-like phenotype.

We explore new paradigms in sensory physiology. We have discovered ‘sensory’ GPCRs of the bitter taste receptor (TAS2R) family and the olfactory receptor (OR) family expressed on the smooth muscle of human bronchi (Nat. Med. 2010; Sci. Rep. 2016; Cell. Signal 2018). TAS2Rs effectively reverse bronchoconstriction by a localized calcium flux that activates, in large part, Ca2+-activated K+ (BKCa) channels–evoking membrane hyperpolarization and smooth muscle relaxation. Human airway smooth muscle cells also express multiple ORs and their obligate downstream olfaction machinery. Of note, activation of OR51E2 via its cognate ligands acetate and propionate results in marked reductions in cytoskeletal remodeling and cellular proliferation. These physiologic outcomes mediated by endogenous metabolic byproducts of the gut microbiota suggest previously unidentified “ancient” chemosensors of the gut-lung axis. The findings also give rise to the notion that ectopic expressions of sensory receptors can be exploited to discover novel disease-modifying therapeutics for asthma.

Current research efforts include: 1) identifying molecular machines primed for sensation in the lung; 2) repurposing the double helix to probe, in real-time, excitation-contraction coupling in smooth muscle shortening; 3) developing ‘bronchi-chip’ that enables chemical and mechanical interrogation into heterotypic cell-to-cell communications; 4) discovering new therapeutic modalities to treat obstructive lung disease; 5) defining the physics of cancer cell migration and invasion; and 6) uncovering the ‘forbidden’ perceptions in metastatic spread of cancers.

Selected Publications:

1. Mendelian randomization analysis reveals a complex genetic interplay among atopic dermatitis, asthma, and GERD. Ahn K, Penn RB, Rattan S, Panettieri RA, Voight BF, and An SS. American Journal of Respiratory and Critical Care Medicine 2023 Jan 15;207(2):130-137.
2. Inhibition of ABCC1 decreases cAMP egress and promotes human airway smooth muscle cell relaxation. Cao G, Lam H, Jude JA, Karmacharya N, Kan M, Jester W, Koziol-White C, Himes BE, Chupp GL, An SS, and Panettieri RA Jr. American Journal of Respiratory Cell and Molecular Biology. 2022 Jan;66(1):96-106.
3. Identification of a β-arrestin-biased negative allosteric modulator for the β2-adrenergic receptor. Ippolito M, De Pascali F, Hopfinger N, Komolov KE, Laurinavichyute D, Reddy PAN, Sakkal LA, Rajkowski KZ, Nayak AP, Lee J, Lee J, Cao G, Donover PS, Reichman M, An SS, Salvino JM, Penn RB, Armen RS, Scott CP, and Benovic BL. Proceedings of the National Academy of Sciences U.S.A. Accepted.
4. Identification and characterization of an atypical Gαs-biased β₂AR agonist that fails to evoke airway smooth muscle cell tachyphylaxis. Kim D, Tokmakova A, Lujan LK, Strzelinski HR, Kim N, Beidokhti MN, Giulianotti MA, Mafi A, Woo JAA, An SS, Goddard WA III, and Liggett SB. Proceedings of the National Academy of Sciences U.S.A. 2021 Dec 7;118(49):e2026668118.
5. The odorant receptor OR2W3 on airway smooth muscle evokes bronchodilation via a cooperative chemosensory tradeoff between TMEM16A and CFTR. Huang J, Lam H, Koziol-White C, Limjunyawong N, Kim D, Kim N, Karmacharya N, Rajkumar P, Firer D, Dalesio NM, Jude J, Kurten RC, Pluznick JL, Deshpande DA, Penn RB, Liggett SB, Panettieri RA Jr, Dong X, and An SS. Proceedings of the National Academy of Science U.S.A. 2020 Nov 10;117(45):28485-28495.
6. A microphysiological model of the bronchial airways reveals the interplay of mechanical and biochemical signals in bronchospasm. Kilic O, Yoon A, Shah SR, Yong HM, Ruiz-Valls A, Chang H, Panettieri RA Jr, Liggett SB, Quiñones-Hinojosa A, An SS, and Levchenko A. Nature Biomedical Engineering2019 Jul;3(7):532-544.
7. AIM1 is an actin-binding protein that suppresses cell migration and micrometastatic dissemination. Haffner MC, Esopi DM, Chaux A, Gürel M, Ghosh S, Vaghasia AM, Tsai H, Kim K, Castagna N, Lam H, Hicks J, Wyhs N, Biswal Shinohara D, Hurley PJ, Simons BW, Schaeffer EM, Lotan TL, Isaacs WB, Netto GJ, De Marzo AM, Nelson WG, An SS, and Yegnasubramanian S. Nature Communications 2017 Jul 26;8(1):142.
8. Directed migration of cancer cells guided by the graded texture of the underlying matrix. Park J, Kim DH, Kim HN, Wang CJ, Kwak MK, Hur E, Suh KY, An SS, and Levchenko A. Nature Materials 2016 Jul;15(7):792-801.
9. Bitter taste receptors on airway smooth muscle bronchodilate by localized calcium signaling and reverse obstruction. Deshpande DA, Wang WC, McIlmoyle EL, Robinett KS, Schillinger RM, An SS, Sham JS, and Liggett SB. Nature Medicine 2010 Nov;16(11):1299-304.
10. Universal physical responses to stretch in the living cell. Trepat X, Deng L, An SS, Navajas D, Tschumperlin DJ, Gerthoffer WT, Butler JP, and Fredberg JJ. Nature 2007 May 31;447(7144):592-5.