The Future of Medicine: Physician-Scientists and Mentorship

For Erica Herzog, MD, PhD, being a mentor is a privilege that is immensely fulfilling.

“There are many pressures that physician-scientists in academic medical centers experience. When you have mentees interested in this career path, it's a treasure,” says Herzog, John Slade Ely Professor of Medicine (Pulmonary), professor of pathology, and associate dean for medical student research at Yale School of Medicine (YSM).

Physician-scientists are met with the demands of balancing clinical duties, research, and teaching. Pair that with the uncertainty of funding, and the challenges can seem insurmountable.

“You have to love what you are doing for it to be worth the time, commitment, and work of having a career where you are pulled in so many directions,” says Herzog.

This summer, two of Herzog’s mentees met career benchmarks. Wonnie Ryu, MD, MPH, received the Ann Theodore Foundation Breakthrough Sarcoidosis Initiative grant for his work on innate immune mechanisms of fibrotic sarcoidosis, and Genta Ishikawa, MD, MPH, was awarded a Parker B. Francis Fellowship in Pulmonary Research for his groundbreaking studies of pulmonary fibrosis neurobiology.

And both credit Herzog and her guidance for getting them there.

“Tireless effort and dedication are essential for success in this challenging career path,” says Ishikawa, instructor of medicine at YSM. “Dr. Herzog has always been candid about this reality, and her support has profoundly motivated me over the past five years. It is one of the key reasons I have been able to persevere and thrive in this demanding environment.”

Herzog completed her residency training at Mount Sinai and came to Yale in 2000 for her pulmonary fellowship. She looks back on this time and recalls how a nightly tradition of reading the journal Cell led to her first mentor at Yale.

“One week, there was an article demonstrating previously unrecognized plasticity of bone marrow stem cells as contributors to tissue regeneration. I thought how amazing it would be if something like this could be done for the lung,” she says.

Herzog was surprised to find that the author was a Yale faculty member—Diane Krause, MD, PhD, Anthony N. Brady Professor of Laboratory Medicine and professor of pathology. Herzog connected with Krause and ultimately joined her lab to work together on basic fundamental mechanisms of tissue repair and regeneration and bone marrow stem cells, all while pursuing her doctoral degree in the Investigative Medicine Program (IMP).

As her mentor, Krause taught Herzog how to ask questions that were important, design experiments that would lead to robust and reproducible results, and frame high-impact papers.

Krause observed how Herzog was an exceptionally motivated and thoughtful pulmonologist when she first joined the laboratory and notes how she grew into a scientist with a clear and confident vision for her future as a physician-scientist.

“She tackled a challenging and controversial research question with remarkable determination. Her rigor, resilience, and intellectual maturity are reflected in the high-impact work she produced—including her first-author publication in Science. It was a privilege to watch Dr. Herzog evolve into the innovative and disciplined investigator she is today,” remarks Krause.

When Herzog completed the IMP program, she faced the decision of staying in the Krause lab to continue basic discovery or pursuing her career goal of translating complex clinical problems into potential treatments. One person she admired for bridging these two goals was Jack Elias, MD, chief of the Section of Pulmonary, Critical Care, and Sleep Medicine at the time. Elias had made patient-relevant discoveries for asthma and airways disease. Herzog met with him to discuss her options.

During their meeting, Elias invited Herzog to join his lab to study neuronal guidance proteins in pulmonary fibrosis. Herzog became a faculty member shortly thereafter, and over the last two decades, she has contributed to new ways to think about lung fibrosis. Elias has witnessed Herzog build on her experiences to become a world leader.

“Watching her clinical and scientific growth and evolving success has been one of the joys of my time at Yale and then Brown,” says Elias, Dean Emeritus and Warren Alpert Foundation Professor of Translational Science, professor of molecular biology, cell biology and biochemistry, and professor of medicine at Brown University.

As a physician-scientist and pulmonologist, she has focused on understanding the intervenable mechanisms of chronic lung disease.

“When you develop a scar, and the wound doesn't heal properly, the skin becomes thickened and does not function as it did before. When that happens in the lung, people have difficulty breathing. There’s no cure, and if the scarring progresses enough, patients can die,” says Herzog.

Her seminal insights revolve around the involvement of innate immunity in pulmonary fibrosis and the neurobiology of the disease. Herzog’s discoveries have furthered understanding of how macrophages are a critical driver of fibrosis and how substances released by injured cells can also contribute to the disease. As part of this work, she discovered that the nervous system develops aberrant communication with the lung during fibrosis, demonstrating a previously unrecognized biology with enormous ramifications for treatment.

During this time she has transitioned from mentee to mentor and finds herself cherishing the role she was once in.

Herzog has mentored over 60 individuals—all at different stages in their careers. While there is no blueprint for a mentor-mentee relationship, there are some guiding principles for a successful one.

Herzog guides her mentees by focusing on patient-relevant work, which is something she learned from her own mentors, Krause and Elias.

“The work we're doing could directly impact patients and may end up saving countless lives. We need to keep that as our focus so we're asking important questions most impactful to patients. Our science needs to be rigorous and reproducible,” she says.

For those early on in their career, publishing findings is especially important, but Herzog stresses that the work is not just about the article in the journal. The fact that a discovery can lead to an intervention that can eradicate a disease—or at least mitigate the consequences—is what is most significant, she says.

Another pearl she passes along is to accept when your hypothesis is wrong, which she considers a philosophical skill that is learned. She often tells her mentees to listen to the science, the data, and view the challenges of a negative story in a positive way. “It's just as important to know what doesn't work because a negative result can inspire you to move in a different direction that can lead to your ultimate discovery,” explains Herzog.

Every mentor-mentee dyad is different—each with their own set of strengths and areas of improvement. Herzog mentions how mentors should have a unique and tailored approach with each mentee.

The dyads set up an individual development plan for short-term goals and long-term aspirations. While weekly check-ins are important, Herzog emphasizes the importance of having benchmark check-ins so they do not lose sight of tangible goals.

“Dr. Herzog goes above and beyond to support our individual career goals,” says Ryu, assistant professor of medicine (pulmonary) at YSM. “It’s important to align your goals and expectations to ensure you’re working toward a shared vision of success. She has empowered each of us to become the best versions of ourselves—as scientists, physicians, and individuals.”

During these meetings, honest assessments are key. Herzog says honesty is one of the best gifts a mentor can give a mentee because that is what will lead to growth. “We're not here to be told that we're fantastic. We're here to develop our skills and ultimately become the physician-scientist we want to be. And the only way that we can do that is if we receive feedback and we learn what we're doing well and what can be improved.”

Herzog learned how to provide feedback by having the mentee first reflect on how an experiment or process went. This helps her understand how the mentee views the situation, so the feedback provided can be framed in such a way that is not received as criticism, but rather as an opportunity to identify what can be improved.

“While many people tend to say what the listener wants to hear, Dr. Herzog is a mentor who tells the truth—with sincerity and the intention to help her mentees grow,” Ishikawa notes.

Ishikawa is grateful for Herzog’s dedication to discussing the broader vision of his project and to working closely to build a meticulous research and career development plan. And Ryu says that there is no one else like her in the world.

“Dr. Herzog’s career arc—from an outstanding trainee, to accomplished physician scientist and generous and effective mentor—epitomizes the very best of our discipline. And at Yale PCCSM, we are fortunate to have amazing faculty like her carry forward this tradition of mentorship and discovery for the good of our patients,” adds Naftali Kaminski, MD, section chief of Pulmonary, Critical Care and Sleep Medicine and Boehringer Ingelheim Pharmaceuticals, Inc. Professor of Medicine.

While the time working together can seem short, the relationship of a mentor and mentee is lifelong, Herzog says, adding that she still calls upon her mentors to this day for their wisdom and perspective.

“As a mentor, you help physician-scientists develop the scientific skills and the critical thinking to be able to become independent. And then they figure out what it is they're going to do, and they go out and do it,” Herzog says, “And that's the best part of my job.”