(From left to right) Xuexiang Han, Michael Mitchell and Mohamad-Gabriel Alameh
The COVID-19 vaccine swiftly undercut the worst of the pandemic for hundreds of millions around the world. Available sooner than almost anyone expected, these vaccines were a triumph of resourcefulness and skill.
Messenger RNA vaccines, like the ones manufactured by Moderna or Pfizer/BioNTech, owed their speed and success to decades of research reinforcing the safety and effectiveness of their unique immune-instructive technology.
In addition to outlining a more flexible and effective COVID-19 vaccine, this work has potential to increase the scope of mRNA vaccines writ large, contributing to prevention and treatment for a range of different illnesses.
Michael Mitchell, associate professor in Penn Engineering’s Department of Bioengineering, Xuexiang Han, postdoctoral fellow in Mitchell’s lab, and Mohamad-Gabriel Alameh, postdoctoral fellow in Drew Weissman’s lab at Penn Medicine and incoming assistant professor in the Department of Pathology and Laboratory Medicine at the Perelman School of Medicine, recently published their findings in Nature Nanotechnology.
mRNA, or messenger ribonucleic acid, is the body’s natural go-between. mRNA contains the instructions our cells need to produce proteins that play important roles in our bodies’ health, including mounting immune responses.
The COVID-19 vaccines follow suit, sending a single strand of RNA to teach our cells how to recognize and fight the virus.
“Macrophages killing cancer cell” photographed by Susan Arnold.
By silencing the molecular pathway that prevents macrophages from attacking our own cells, Penn Engineers have manipulated these white blood cells to eliminate solid tumors.
Cancer remains one of the leading causes of death in the U.S. at over 600,000 deaths per year. Cancers that form solid tumors such as in the breast, brain or skin are particularly hard to treat. Surgery is typically the first line of defense for patients fighting solid tumors. But surgery may not remove all cancerous cells, and leftover cells can mutate and spread throughout the body. A more targeted and wholistic treatment could replace the blunt approach of surgery with one that eliminates cancer from the inside using our own cells.
Dennis Discher, Robert D. Bent Professor in Chemical and Biomolecular Engineering, Bioengineering, and Mechanical Engineering and Applied Mechanics, and postdoctoral fellow, Larry Dooling, provide a new approach in targeted therapies for solid tumor cancers in their study, published in Nature Biomedical Engineering. Their therapy not only eliminates cancerous cells, but teaches the immune system to recognize and kill them in the future.
“Due to a solid tumor’s physical properties, it is challenging to design molecules that can enter these masses,” says Discher. “Instead of creating a new molecule to do the job, we propose using cells that ‘eat’ invaders – macrophages.”
Macrophages, a type of white blood cell, immediately engulf and destroy – phagocytize – invaders such as bacteria, viruses, and even implants to remove them from the body. A macrophage’s innate immune response teaches our bodies to remember and attack invading cells in the future. This learned immunity is essential to creating a kind of cancer vaccine.
But, a macrophage can’t attack what it can’t see.
“Macrophages recognize cancer cells as part of the body, not invaders,” says Dooling. “To allow these white blood cells to see and attack cancer cells, we had to investigate the molecular pathway that controls cell-to-cell communication. Turning off this pathway – a checkpoint interaction between a protein called SIRPa on the macrophage and the CD47 protein found on all ‘self’ cells – was the key to creating this therapy.”
Multiple members in the biophysical engineering lab lead by Dennis Discher, including co-lead author and postdoctoral fellow and Penn Bioengineering alumnus Jason Andrechak and Bioengineering Ph.D. student Brandon Hayes, contributed to this study. The research was funded by grants from the National Heart, Lung, and Blood Institute and the National Cancer Institute, including the Physical Sciences Oncology Network, of the US National Institutes of Health.
Members of the inaugural cohort of fellows in the Center for Innovation and Precision Dentistry (CiPD)’s NIDCR T90/R90 Postdoctoral Training Program have been recognized for their research activities with fellows receiving awards from the American Association for Dental, Oral, and Craniofacial Research (AADOCR), the Society for Biomaterials, and the Osteology Foundation. All four of the honored postdocs are affiliated with Penn Bioengineering.
Zhi Ren
Zhi Ren won first place in the Fives-Taylor Award at the AADOCR Mini Symposium for Young Investigators. A postdoctoral fellow in the labs of Dr. Hyun (Michel) Koo at Penn Dental Medicine (and member of the Penn Bioengineering Graduate Group) and Dr. Kathleen Stebe of Penn Engineering, Dr. Ren’s research focuses on understanding how bacterial and fungal pathogens interact in the oral cavity to form a sticky plaque biofilm on teeth, which gives rise to severe childhood tooth decay that affects millions of children worldwide. In his award-winning study, titled “Interkingdom Assemblages in Saliva Display Group-Level Migratory Surface Mobility”, Dr. Ren discovered that bacteria and fungi naturally present in the saliva of toddlers with severe decay can form superorganisms able to move and rapidly spread on tooth surfaces.
Justin Burrell
Justin Burrell won second place in the AADOCR Hatton Competition postdoctoral category for his research. Dr. Burrell has been working with Dr. Anh Le in Penn Dental Medicine’s Department of Oral Surgery/Pharmacology and Dr. D. Kacy Cullen of Penn Medicine and Penn Bioengineering. Together, their interdisciplinary team of clinician-scientists, biologists, and neuroengineers have been developing novel therapies to expedite facial nerve regeneration and increase meaningful functional recovery.
Marshall Padilla
Marshall Padilla earned third place at the Society for Biomaterials Postdoctoral Recognition Award Competition for a project titled, “Branched lipid architecture improves lipid-nanoparticle-based mRNA delivery to the liver via enhanced endosomal escape”. Padilla was also a finalist in the AADOCR Hatton Award Competition, presenting on a separate project titled, “Lipid Nanoparticle Optimization for mRNA-based Oral Cancer Therapy”. Both projects employ lipid nanoparticles, the same delivery vehicles used in the mRNA COVID-19 vaccine technology. A postdoctoral fellow in the lab of Dr. Michael J. Mitchell of Penn’s Department of Bioengineering, Dr. Padilla’s research focuses on developing new ways to enhance the efficacy and safety of lipid nanoparticle technology and its applications in dentistry and biomedicine. He has been working in collaboration with Dr. Shuying (Sheri) Yang and Dr. Anh Le in Penn Dental Medicine.
Dennis Sourvanos
Dennis Sourvanos (GD’23, DScD’23) was the recipient of the Trainee Travel Grant award through the Osteology Foundation (Lucerne Switzerland). Dr. Sourvanos will be presenting his research related to medical dosimetry and tissue regeneration at the International Osteology Symposium in Barcelona, Spain (April 27th – 29th 2023). He also presented at the 2023 AADOCR/CADR Annual Meeting for his project titled, “Validating Head-and-Neck Human-Tissue Optical Properties for Photobiomodulation and Photodynamic Therapies.” Dr. Sourvanos has been working with Dr. Joseph Fiorellini in Penn Dental Medicine’s Department of Periodontics and Dr. Timothy Zhu in the Hospital of the University of Pennsylvania’s Department of Radiation Oncology and the Smilow Center for Translational Research (and member of the Penn Bioengineering Graduate Group).
The model of tubule packing developed by the Hughes Lab shows the tubules repelling each other and shifting around.
A recent study by Penn Bioengineering researchers sheds new light on the role of physics in kidney development. The kidney uses structures called nephrons and tubules to filter blood and pass urine to the bladder. Nephron number is set at birth and can vary over an order of magnitude (anywhere from 100,000 to over a million nephrons in an individual kidney). While the reasons for this variability remain unclear, low numbers of nephrons predispose patients to hypertension and chronic kidney disease.
Now, research published in Developmental Cell led by Alex J. Hughes, Assistant Professor in the Department of Bioengineering, demonstrates a new physics-driven approach to better visualize and understand how a healthy kidney develops to avoid organizational defects that would impair its function. While previous efforts have typically approached this problem using molecular genetics and mouse models, the Hughes Lab’s physics-based approach could link particular types of defects to this genetic information and possibly highlight new treatments to prevent or fix congenital defects.
Alex J. Hughes, Assistant Professor in Bioengineering
Louis Prahl, NIH F32 Postodctoral Fellow
During embryonic development, kidney tubules grow and the tips divide to make a branched tree with clusters of nephron stem cells surrounding each branch tip. In order to build more nephrons, the tree needs to grow more branches. To keep the branches from overlapping, the kidney’s surface grows more crowded as the number of branches increase. “At this point, it’s like adding more people to a crowded elevator,” says Louis Prahl, first author of the paper and Postdoctoral Fellow in the Hughes Lab. “The branches need to keep rearranging to accommodate more until organ growth stops.”
To understand this process, Hughes, Prahl and their team investigated branch organization in mouse kidneys as well as using computer models and a 3D printed model of tubules. Their results show that tubules have to actively restructure – essentially divide at narrower angles – to accommodate more tubules. Computer simulations also identified ‘defective’ packing, in which the simulation parameters caused tubules to either overlap or be forced beneath the kidney surface. The team’s experimentation and analysis of published studies of genetic mouse models of kidney disease confirmed that these defects do occur.
This study represents a unique synthesis of different fields to understand congenital kidney disease. Mathematicians have studied geometric packing problems for decades in other contexts, but the structural features of the kidney present new applications for these models. Previous models of kidney branching have approached these problems from the perspective of individual branches or using purely geometric models that don’t account for tissue mechanics. By contrast, The Hughes Lab’s computer model demonstrates the physics of how tubule families interact with each other, allowing them to identify ‘phases’ of kidney organization that either relate to normal kidney development or organizational defects. Their 3D printed model of tubules shows that these effects can occur even when one sets the biology aside.
Hughes has been widely recognized for his research in the understanding of kidney development. This new publication is the first fruit of his 2021 CAREER Award from the National Science Foundation (NSF) and he was recently named a 2023 Rising Star by the Cellular and Molecular Bioengineering (CMBE) Special Interest Group. In 2020 he became the first Penn Engineering faculty member to receive the Maximizing Investigators’ Research Award (MIRA) from the National Institutes of Health (NIH) for his forward-thinking work in the creation of new tools for tissue engineering.
Pediatric nephrologists have long worked to understand the cause of these childhood kidney defects. These efforts are often confounded by a lack of evidence for a single causative mutation. The Hughes Lab’s approach presents a new and different application of the packing problem and could help answer some of these unsolved questions and open doors to prevention of these diseases. Following this study, Hughes and his lab members will continue to explore the physics of kidney tubule packing, looking for interesting connections between packing organization, mechanical stresses between neighboring tubule tips, and nephron formation while attempting to copy these principles to build stem cell derived tissues to replace damaged or diseased kidney tissue. Mechanical forces play an important role in developmental biology and there is much scope for Hughes, Prahl and their colleagues to learn about these properties in relation to the kidney.
Other authors include Bioengineering Ph.D. students and Hughes Lab members John Viola and Jiageng Liu.
This work was supported by NSF CAREER 2047271, NIH MIRA R35GM133380, Predoctoral Training Program in Developmental Biology T32HD083185, and NIH F32 fellowship DK126385.
Researchers at Penn and colleagues have developed a tool to analyze single cells that assesses both the patterns of gene activation within a cell and which sibling cells shared a common progenitor.
Arjun Raj of the School of Engineering and Applied Science and the Perelman School of Medicine, former postdoc Lee Richman, now of Brigham and Women’s Hospital, and colleagues have developed a new analysis tool that combines a cell’s unique gene expression data with information about the cell’s origins. The method can be applied to identify new cell subsets throughout development and better understand drug resistance.
Recent advances in analyzing data at the single-cell level have helped biologists make great strides in uncovering new information about cells and their behaviors. One commonly used approach, known as clustering, allows scientists to group cells based on characteristics such as the unique patterns of active or inactive genes or by the progeny of duplicating cells, known as clones, over several generations.
Although single-cell clustering has led to many significant findings, for example, new cancer cell subsets or the way immature stem cells mature into “specialized” cells, researchers to this point had not been able to marry what they knew about gene-activation patterns with what they knew about clone lineages.
Now, research published in Cell Genomics led by University of Pennsylvania professor of bioengineering Arjun Raj has resulted in the development of ClonoCluster, an open-source tool that combines unique patterns of gene activation with clonal information. This produces hybrid cluster data that can quickly identify new cellular traits; that can then be used to better understand resistance to some cancer therapies.
“Before, these were independent modalities, where you would cluster the cells that express the same genes in one lot and cluster the others that share a common ancestor in another,” says Lee Richman, first paper author and a former postdoc in the Raj lab who is now at Brigham and Women’s Hospital in Boston. “What’s exciting is that this tool allows you to draw new lines around your clusters and explore their properties, which could help us identify new cell types, functions, and molecular pathways.”
Researchers in the Raj Lab use a technique known as barcoding to assign labels to cells they are interested in studying, particularly useful for tracking cells, clustering data based on cells’ offspring, and following lineages over time. Believing they could parse more valuable information out of this data by incorporating the cell’s unique patterns of gene activation, the researchers applied ClonoCluster to six experimental datasets that used barcoding to track dividing cells’ offspring. Specifically, they looked at the development of chemotherapy resistance and of stem cells into specialized tissue types.
“Padilla came to the CiPD training program earlier this year with a Ph.D. in Chemistry from the University of Wisconsin-Madison. He is currently a postdoctoral fellow in the lab of Dr. Michael J. Mitchell of Penn’s Department of Bioengineering, where his research focuses on developing new materials to enhance the efficacy and safety of biological therapeutics. While passionate about research, he also has a strong interest in developing mentoring relationships and in teaching. At Wisconsin, Marshall earned a certificate in research, teaching, and learning, in which he conducted a research project on developing positive metacognitive practices in introductory organic chemistry. Additionally, he taught a course on mentoring in a research setting, and is passionate about promoting diversity and inclusiveness in biomedical sciences.”
Buffone got his Ph.D. in Chemical Engineering from SUNY Buffalo in Buffalo, NY in 2012, working with advisor Sriram Neelamegham, Professor of Chemical and Biological Engineering. Buffone completed previous postdoctoral studies at Roswell Park Comprehensive Cancer Center with Joseph T.Y. Lau, Distinguished Professor of Oncology in the department of Cellular and Molecular Biology. Upon coming to Penn in 2015, Buffone has worked in the Hammer Lab under advisor Daniel A. Hammer, Alfred G. and Meta A. Ennis Professor in Bioengineering and in Chemical and Biomolecular Engineering, first as a postdoc and later a research associate. Buffone also spent a year as a Visiting Scholar in the Center for Bioengineering and Tissue Regeneration, directed by Valerie M. Weaver, Professor at the University of California, San Francisco in 2019.
While at Penn, Buffone was a co-investigator on an R21 grant through the National Institutes of Health (NIH) which supported his time as a research associate. Buffone is excited to start his own laboratory where he plans to train a diverse set of trainees.
Buffone’s research area lies at the intersection of genetic engineering, immunology, and glycobiology and addresses how to specifically tailor the trafficking and response of immune cells to inflammation and various diseases. The work seeks to identify and subsequently modify critical cell surface and intracellular signaling molecules governing the recruitment of various blood cell types to distal sites. The ultimate goal of his research is to tailor and personalize the innate and adaptive immune response to specific diseases on demand.
“None of this would have been possible without the unwavering support of all of my mentors, past and present, and most especially Dan Hammer,” Buffone says. “His support in helping me transition into an independent scientist and his understanding of my outside responsibilities as a dad with two young children is truly the reason why I am standing here today. It’s a testament to Dan as both a person and a mentor.”
The inaugural class of the CiPD NIDCR T90/R90 Postdoctoral Training Program Fellows with Dean Mark Wolff (center); Dr. Michel Koo, Founding Director of CiPD (far right); and CiPD Co-Director Dr. Kathleen Stebe of Penn’s School of Engineering and Applied Science (far left).
With one of its key missions to develop a new generation of scientists at the interface of dental medicine and engineering, the Center for Innovation & Precision Dentistry (CiPD) has selected its inaugural class of fellows for its new postdoctoral training program.
The CiPD was awarded a $2.5 million T90/R90 grant from the National Institute of Dental and Craniofacial Research (NIDCR) last summer to establish the program, recently naming this first cohort of fellows that includes Justin Burrell, Marshall Padilla, Zhi Ren, and Dennis Sourvanos.
“We’re hoping this program will promote cross-pollination and create a culture between these two fields to help dentists develop innovative strategies with engineers,” says Penn Dental Medicine’s Michel Koo, Co-Director of CiPD, who launched the Center in 2021 with Co-Director Kathleen Stebe, Richer & Elizabeth Goodwin Professor in Penn Engineering’s Department of Chemical and Biomolecular Engineering. “Dentists can learn from engineering principles and tools, and engineers can understand more about the needs of the dental and craniofacial fields. We’re providing a platform for them to work together to address unmet clinical needs and develop careers in that interface.”
The NIDCR T90/R90 Postdoctoral Training Program aims to specifically focus on the oral microbiome, host immunity, and tissue regeneration, each of which ties into different aspects of oral health, from tooth decay and periodontal disease to the needs of head and neck cancer patients. To advance these areas, emerging approaches, from advanced materials, robotics, and artificial intelligence to tissue engineering, chloroplast- and nanoparticle-based technologies, will be leveraged.
As part of the two-year training, each postdoc will receive co-mentorship from faculty from each school in conjunction with a career development committee of clinicians, basic scientists, as well as engineers. These mentorships will be focused on research outcomes and readying participants to submit grants and compete for positions in academia or industry.
The inaugural class of fellows includes Justin Burrell, a postdoctoral student in the lab of D. Kacy Cullen, Associate Professor of Neurosurgery; Marshall Padilla, a postdoc in the lab of Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in Bioengineering; and Zhi Ren, a postdoc in the lab of Michael Koo; and Dennis Sourvanos, an Advanced Graduate Dental Education resident at Penn Dental Medicine whose research has been co-directed by Timothy C. Zhu, Professor of Radiation Oncology in the Perelman School of Medicine. Cullen, Mitchell, Koo and Zhu are all members of the Penn Bioengineering Graduate Group.
Spencer Haws, Postdoctoral Research Fellow in the laboratory of Jennifer E. Phillips-Cremins, Associate Professor and Dean’s Faculty Fellow in Bioengineering and in Genetics, was awarded a 2022 Druckenmiller Fellowship from the New York Stem Cell Foundation Research Institute (NYSCF). This prestigious program is the largest dedicated stem cell fellowship program in the world and was developed to train and support young scientists working on groundbreaking research in the field of stem cell research. Haws is one of only five inductees into the 2022 class of fellows.
Haws earned his Ph.D. in Nutritional Sciences in 2021 from the University of Wisconsin-Madison, where he studied metabolism-chromatin connections under the mentorship of John Denu, Professor in Biomolecular Chemistry at the University of Wisconsin-Madison. As a NYSCF – Druckenmiller Fellow in the Cremins Laboratory for Genome Architecture and Spatial Neurobiology, Haws is using this previously developed expertise to frame his investigations into the underlying mechanisms driving the neurodegenerative disorder fragile X syndrome (FXS). “Ultimately, I hope that this work will help guide the development of future FXS-specific therapeutics of which none currently exist,” says Haws.
Qazi obtained his Ph.D. at the Technical University of Berlin and the Charité Hospital in Berlin, Germany working on translational approaches for musculoskeletal tissue repair using biomaterials and stem cells under the co-advisement of Georg Duda, Director of the Berlin Institute of Health and David Mooney, Mercator Fellow at Charité – Universitätsmedizin Berlin. After arriving at Penn in 2019, Qazi performed research on microscale granular hydrogels in the Polymeric Biomaterials Laboratory of Jason Burdick, Adjunct Professor in Bioengineering at Penn and Bowman Endowed Professor in Chemical and Biological Engineering at the University of Colorado, Boulder. While conducting postdoctoral research, Qazi also collaborated with the groups of David Issadore, Associate Professor in Bioengineering and in Electrical and Systems Engineering, and Daeyeon Lee, Professor and Evan C. Thompson Term Chair for Excellence in Teaching in Chemical and Biomolecular Engineering and member of the Penn Bioengineering Graduate Group. Qazi’s postdoctoral research was supported through a fellowship from the German Research Foundation, and resulted in several publications in high-profile journals, including Advanced Materials, Cell Stem Cell, Small, and ACS Biomaterials Science and Engineering.
“Taimoor has done really fantastic research as a postdoctoral fellow in the group,” says Burdick. “Purdue has a long history of excellence in biomaterials research and will be a great place for him to build a strong research program.”
Qazi’s future research program will engineer biomaterials to make fundamental and translational advances in musculoskeletal tissue engineering, including the study of how rare tissue-resident cells respond to spatiotemporal signals and participate in tissue repair, and developing modular hydrogels that permit minimally invasive delivery for tissue regeneration. The ultimate goal is to create scalable, translational, and biologically inspired healthcare solutions that benefit a patient population that is expected to grow manifold in the coming years.
Qazi is looking to build a strong and inclusive team of scientists and engineers with diverse backgrounds interested in tackling problems at the interface of translational medicine, materials science, bioengineering, and cell biology, and will be recruiting graduate students immediately. Interested students can contact him directly at thqazi@seas.upenn.edu.
“I am excited to launch my independent research career at a prestigious institution like Purdue,” says Qazi. “Being at Penn and particularly in the Department of Bioengineering greatly helped me prepare for the journey ahead. I am grateful for Jason’s mentorship over the years and the access to resources provided by Jason, Dave Issadore, Ravi, Dave Meany and other faculty which support the training and professional development of postdoctoral fellows in Penn Bioengineering.”
Congratulations to Dr. Qazi from everyone at Penn Bioengineering!
