Roman Dziarski
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Roman Dziarski (Polish pronunciation: IPA: /ˈrɔ.man//ˈd͡ʑar.ski/ born December 11, 1949) is a Polish-born American immunologist and
microbiologist A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of par ...
. He is best known for his research on
innate immunity The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system). The innate immune system is an alternate defense strategy and is the dominant immune s ...
and bacterial
peptidoglycan Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that forms a mesh-like layer (sacculus) that surrounds the bacterial cytoplasmic membrane. The sugar component consists of alternating ...
, for discovering the family of human
peptidoglycan recognition protein Peptidoglycan recognition proteins (PGRPs) are a group of highly conserved pattern recognition receptors with at least one peptidoglycan recognition protein domain, domain capable of recognizing the peptidoglycan component of the cell wall of bact ...
s, which comprises PGLYRP1, PGLYRP2, PGLYRP3, and PGLYRP4, and for defining the functions of these proteins. Dziarski is currently Professor Emeritus of Microbiology and Immunology at
Indiana University School of Medicine The Indiana University School of Medicine (IUSM) is a major, multi-campus medical school located throughout the US state, U.S. state of Indiana and is both the Medical school, undergraduate and Graduate medical education, graduate medical school o ...
.


Education

From 1963 to 1967, Dziarski received his secondary education at Reytan High School (Polish: ''VI Liceum Ogólnokształcące im. Tadeusza Reytana'') in Warsaw, Poland, under the tutelage of the revered pedagogue, . From 1967 to 1972, Dziarski attended the
University of Warsaw The University of Warsaw (, ) is a public university, public research university in Warsaw, Poland. Established on November 19, 1816, it is the largest institution of higher learning in the country, offering 37 different fields of study as well ...
with a major in
Biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
and
Microbiology Microbiology () is the branches of science, scientific study of microorganisms, those being of unicellular organism, unicellular (single-celled), multicellular organism, multicellular (consisting of complex cells), or non-cellular life, acellula ...
, which he studied under . He received his Bachelor of Sciences (BS) degree in 1971, and Master of Science (MS) degree in 1972. His MS Thesis was titled, ''Phenotypic expression of spontaneous mutations to nalidixic acid resistance in Escherichia coli K-12'', with Roman Mycielski as his thesis advisor. From 1972 to 1973, Dziarski studied English at West London College in London, England. From 1973 to 1977, Dziarski was a Research Scientist in the Department of Bacteriology at the National Institute of Public Health (Polish: '' Narodowy Instytut Zdrowia Publicznego – Państwowy Zakład Higieny''), Warsaw, Poland, where he performed research for his Doctor of Philosophy (Ph.D.) degree, which culminated in 1977 with the defense of his Ph.D. thesis, titled, ''Immunobiological properties of Staphylococcus aureus cell wall polysaccharides'', with Janusz Jeljaszewicz as his thesis advisor. In September 1977, Dziarski emigrated to the USA.


Academic positions

In 1977, Dziarski joined the Department of Microbiology, Immunology and Pathology at
Temple University School of Podiatric Medicine Temple University (Temple or TU) is a public state-related research university in Philadelphia, Pennsylvania, United States. It was founded in 1884 by the Baptist minister Russell Conwell and his congregation at the Grace Baptist Church of Phil ...
in Philadelphia, Pennsylvania, USA, as a research associate and assistant professor. In 1978, he was promoted to assistant professor and in 1981 to associate professor. In 1985, Dziarski moved to the Department of Microbiology and Immunology at
Indiana University School of Medicine The Indiana University School of Medicine (IUSM) is a major, multi-campus medical school located throughout the US state, U.S. state of Indiana and is both the Medical school, undergraduate and Graduate medical education, graduate medical school o ...
–Northwest, in Gary, Indiana, USA, as an associate professor and a full member of the
Indiana University Indiana University (IU) is a state university system, system of Public university, public universities in the U.S. state of Indiana. The system has two core campuses, five regional campuses, and two regional centers under the administration o ...
Graduate School, in Bloomington, Indiana, USA. In 1991, Dziarski was promoted to a Full Professor of Microbiology and Immunology with tenure. He held this position until his retirement in 2021, when he became Professor Emeritus of Microbiology and Immunology.


Scientific contributions


Role of peptidoglycan in innate immunity

In his early research, Dziarski focused on the role of bacterial peptidoglycan in innate immunity. He showed that peptidoglycan is an immunomodulator and a polyclonal activator of
B lymphocytes B cells, also known as B lymphocytes, are a type of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasm ...
. He determined the role of DNA synthesis, intracellular calcium,
protein kinase C In cell biology, protein kinase C, commonly abbreviated to PKC (EC 2.7.11.13), is a family of protein kinase enzymes that are involved in controlling the function of other proteins through the phosphorylation of hydroxyl groups of serine and t ...
, and inhibitory G proteins in peptidoglycan-induced polyclonal B lymphocyte activation. He also established the role of peptidoglycan and other polyclonal B cell activators in the induction of autoantibody responses in various models of
autoimmunity In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an " autoimmune disease ...
.


Peptidoglycan receptors and cell activation pathways

In his subsequent research, Dziarski set out to identify peptidoglycan receptors on immune cells that mediate the cell-activating and immunomodulating effects of peptidoglycan. His early attempts using biochemical methods were not successful, as they were prone to nonspecific interactions and technical artifacts. He also showed that similar problems and artifacts plagued the early attempts to identify the cell receptors for bacterial
lipopolysaccharide Lipopolysaccharide (LPS), now more commonly known as endotoxin, is a collective term for components of the outermost membrane of the cell envelope of gram-negative bacteria, such as '' E. coli'' and ''Salmonella'' with a common structural archit ...
and other cell activators. The molecular biology approach to identifying the cell-activating peptidoglycan receptors was more successful. Using this approach, Dziarski and his research group, in collaboration with Dipika Gupta and her group (also at Indiana University School of Medicine), identified
CD14 CD14 ( cluster of differentiation 14) is a human protein made mostly by macrophages as part of the innate immune system. It helps to detect bacteria in the body by binding lipopolysaccharide (LPS), a pathogen-associated molecular pattern (PAMP). ...
as the cell-activating receptor for peptidoglycan and showed that CD14 physically binds peptidoglycan. Furthermore, Dziarski's and Gupta's groups identified the involvement of several signal transduction molecules and pathways in peptidoglycan-induced cell activation. Dziarski also established that
chemokine Chemokines (), or chemotactic cytokines, are a family of small cytokines or signaling proteins secreted by cells that induce directional movement of leukocytes, as well as other cell types, including endothelial and epithelial cells. In addit ...
s are the main pro-inflammatory mediators in human
monocyte Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and monocyte-derived dendritic cells. As a part of the vertebrate innate immune system monocytes also ...
s activated by peptidoglycan and other bacterial cell activators. Using similar molecular biology approach the research groups of Carsten J. Kirschning (at Tularik Inc.) and Douglas Golenbock (at
Boston University School of Medicine The Boston University School of Medicine (formally the Chobanian and Avedisian School of Medicine) is the medical school of Boston University, a private university, private research university in Boston, Boston, Massachusetts. It was founded in ...
) in collaboration with Dziarski, discovered that
TLR2 Toll-like receptor 2 also known as TLR2 is a protein that in humans is encoded by the ''TLR2'' gene. TLR2 has also been designated as CD282 (cluster of differentiation 282). TLR2 is one of the toll-like receptors and plays a role in the immune sy ...
is the cell-activating receptor for peptidoglycan and other components of
Gram-positive bacteria In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain ...
. In the follow-up studies, Dziarski's and Gupta's groups identified the signal transduction pathway activated by peptidoglycan through TLR2 and verified that TLR2 is indeed the peptidoglycan cell-activating receptor.


Discovery of peptidoglycan recognition proteins

Dziarski's best known contribution to
innate immunity The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system). The innate immune system is an alternate defense strategy and is the dominant immune s ...
is his research on mammalian
peptidoglycan recognition protein Peptidoglycan recognition proteins (PGRPs) are a group of highly conserved pattern recognition receptors with at least one peptidoglycan recognition protein domain, domain capable of recognizing the peptidoglycan component of the cell wall of bact ...
s (PGRPs). In 2001, Dziarski's and Gupta's groups discovered and cloned three human PGRPs, which they named PGRP-L, PGRP-Iα, and PGRP-Iβ (for long and intermediate size transcripts). They established that the human genome codes for a family of 4 PGRPs: PGRP-S (short PGRP), PGRP-L, PGRP-Iα, and PGRP-Iβ. Subsequently, the Human Genome Organization Gene Nomenclature Committee changed the gene symbols of PGRP-S, PGRP-L, PGRP-Iα, and PGRP-Iβ to '' PGLYRP1'', '' PGLYRP2'', '' PGLYRP3'', and '' PGLYRP4'', respectively, and this nomenclature is currently also used for other mammalian PGRPs. Dziarski and his collaborators showed that mammalian PGRPs are selectively expressed in immune and
epithelial cells Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
.


Functions of peptidoglycan recognition proteins

Dziarski and his collaborators established that all
mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
ian PGRPs bind bacterial peptidoglycan. Then, they identified the functions of human PGRPs: PGLYRP2 is a peptidoglycan-lytic enzyme, ''N''-acetylmuramoyl-L-alanine amidase, and PGLYRP1, PGLYRP3, and PGLYRP4 are directly bactericidal for both Gram-positive and
Gram-negative bacteria Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the Crystal violet, crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelo ...
. In further research, Dziarski's group established the mechanism of bacterial killing by human PGRPs. They showed that human PGRPs kill bacteria by simultaneously inducing three synergistic stress responses: oxidative stress, thiol stress, and metal stress, by interfering with the function of the bacterial respiratory electron transport chain. Dziarski also showed that bacterial killing by these PGRPs does not involve cell membrane permeabilization, cell wall hydrolysis, or osmotic shock, but is synergistic with
antibacterial peptides Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for ...
.


Cloning and functions of zebrafish peptidoglycan recognition proteins

Collaborative research of Dipika Gupta's and Dziarski's groups also identified and cloned three
zebrafish The zebrafish (''Danio rerio'') is a species of freshwater ray-finned fish belonging to the family Danionidae of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (an ...
PGRPs and showed that they are highly expressed in eggs, developing embryos, and adult tissues that contact the external environment. They further showed that these PGRPs have both peptidoglycan-lytic amidase and bactericidal activities and are essential for defense against bacterial infections and survival of the developing zebrafish embryos.


In vivo role of mammalian peptidoglycan recognition proteins

Dziarski's group also identified several
in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, an ...
functions of mammalian PGRPs. Dziarski showed that despite their bactericidal activity, mammalian PGRPs have only a limited role in defense against
infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...
s. Intranasal application of PGLYRP3 or PGLYRP4 in mice protects from intranasal lung infection with ''
Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posi ...
'' and ''Escherichia'' ''coli'', and ''PGLYRP1''-deficient mice are more sensitive to systemic infections with non-pathogenic bacteria (''
Micrococcus luteus ''Micrococcus luteus'' is a Gram-positive to Gram-variable, nonmotile, tetrad-arranging, pigmented, saprotrophic coccus bacterium in the family Micrococcaceae. It is urease and catalase positive. An obligate aerobe, ''M. luteus'' is found in soi ...
'' and ''Bacillus'' ''subtilis''). Dziarski's group further showed that mouse PGRPs play a role in maintaining healthy
microbiome A microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps ''et al.'' as "a characteristic microbial community occupying a reasonably wel ...
, because ''PGLYRP1''-, ''PGLYRP2''-, ''PGLYRP3''-, and ''PGLYRP4''-deficient mice have significant changes in the composition of their intestinal microbiomes. ''PGLYRP1''-deficient mice also have changes in their lung microbiome. Dziarski's and Gupta's groups further showed that mouse PGRPs play a role in maintaining anti- and pro- inflammatory homeostasis in the intestine, skin, lungs, and joints. They demonstrated that all four PGLYRPs protect mice from dextran sodium sulfate (DSS)-induced
colitis Colitis is swelling or inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and ...
and the effect of ''PGLYRP2'' and ''PGLYRP3'' on the intestinal microbiome is responsible for this protection. They showed that PGLYRP3 and PGLYRP4 are anti-inflammatory and protect mice from experimentally induced
atopic dermatitis Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin. Atopic dermatitis is also often called simply eczema but the same term is also used to refer to dermatitis, the larger group of skin conditi ...
, and PGLYRP2 is also anti-inflammatory and protects mice from experimentally induced
psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete b ...
-like inflammation. They also showed that some PGRPs have opposite effects, i.e., PGLYRP2 also has a pro-inflammatory effect, as it promotes the development of experimental
arthritis Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...
, and PGLYRP1 is pro-inflammatory and promotes experimentally induced
asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
and skin
inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
in mice. The pro-inflammatory effect of PGLYRP1 on asthma depends on the PGLYRP1-regulated intestinal microbiome.


Disease associations of peptidoglycan recognition proteins

In collaborative research, Dipika Gupta's and Dziarski's groups showed that patients with two forms of
inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis (UC) being the principal types. Crohn's disease affects the small intestine and large intestine ...
(IBD),
Crohn's disease Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea, fever, abdominal distension, and weight loss. Complications outside of the ...
and
ulcerative colitis Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBD), with the other type being Crohn's disease. It is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary sympto ...
, have significantly more frequent missense variants in all four ''PGLYRP'' genes than healthy control individuals. These results suggest that PGRPs may protect humans from these inflammatory diseases, and that mutations in ''PGLYRP'' genes may be among the genetic factors predisposing to these diseases.


Publications and research support

Dziarski authored over 150 scientific publications, which have over 15,000 citations,
h-index The ''h''-index is an author-level metric that measures both the productivity and citation impact of the publications, initially used for an individual scientist or scholar. The ''h''-index correlates with success indicators such as winning t ...
of 54, and i10-index of 92. From 1979 to 2020, Dziarski was a Principal Investigator on more than 20 research grants, including 10 awards from the
National Institutes of Health The National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. It was founded in 1887 and is part of the United States Department of Health and Human Service ...
.


Teaching

Dziarski is a dedicated educator. From 1978 to 1984, he taught Immunology and Microbiology to
podiatric medicine Podiatry ( ), also know as podiatric medicine and surgery ( ), is a branch of medicine devoted to the study, diagnosis, and treatment of disorders of the foot, ankle and lower limb. The healthcare professional is known as a podiatrist. The US ...
students at Temple University School of Podiatric Medicine. From 1985 to 2020, he taught Immunology, Microbiology, and elements of Pathology and Pharmacology to medical students at Indiana University School of Medicine–Northwest. He was a Course Director of Microbiology and Immunology, and in 1990 introduced an innovative
Problem-Based Learning Problem-based learning (PBL) is a teaching method in which students learn about a subject through the experience of solving an open-ended problem found in trigger material. The PBL process does not focus on problem solving with a defined solution ...
curriculum. He authored a chapter on Innate Immunity, published in three editions of the popular medical textbook, ''Schaechter’s Mechanisms of Microbial Disease'', and a chapter on peptidoglycan in ''Molecular Medical Microbiology'' textbook. Dziarski received seven Teaching Awards at Indiana University.


World War II book

In 2023 Dziarski published a World War II family memoir, “''How We Outwitted and Survived the Nazis: The True Story of the Holocaust Rescuers, Zofia Sterner and Her Family''”, which received positive reviews. Polish translation was published in 2025.


Awards and honors

* Stanford University List of World’s Top 2% Scientists, ranked in the top 0.5% to 0.7% of world’s scientists (2018-2024) * Indiana University Trustees’ Teaching Awards (2001, 2012, and 2018) * Indiana University School of Medicine Class of 2016 Faculty Teaching Award (2016) * Indiana University Outstanding Educator (2012, 2013, and 2014) * Innovation Fellow Award from the Society of Innovators, sponsored by Ivy Tech State College in Indiana (2007) * Joseph A. Negri Trust Award and Dedication of the Laboratory (2006) * Indiana University School of Medicine Eminent Scholar (1998 – 1999) * Editorial Board of ''Infection and Immunity'', the official journal of the American Society for Microbiology (1982 – 2020) * Editorial Board of ''Current Immunology Reviews'' (2004 – 2020) * Member of the American Association of Immunologists and Federation of American Societies for Experimental Biology (1982 – 2020) * Member of the American Society for Microbiology (1978 – 2020) * Dean's Award to the Best Graduating Student at the Faculty of Biology, University of Warsaw, Poland (1971)


Family

Dziarski's mother (Janina Dziarska, née Domańska) and father (Kazimierz W. Dziarski) were both dentists in Warsaw, Poland. Dziarski was married to Agnes Dziarski (née Rewkiewicz), a dentist, from 1971 to 1994. In 1996, Dziarski married Dipika Gupta, a biochemist and molecular biologist at Indiana University School of Medicine. Dziarski has three children: Matthew Dziarski, Alisha Dziarski, and Anjali Dziarski.


See also

*
Peptidoglycan recognition protein Peptidoglycan recognition proteins (PGRPs) are a group of highly conserved pattern recognition receptors with at least one peptidoglycan recognition protein domain, domain capable of recognizing the peptidoglycan component of the cell wall of bact ...
s * PGLYRP1 * PGLYRP2 * PGLYRP3 * PGLYRP4


References

{{DEFAULTSORT:Dziarski, Roman Polish microbiologists Scientists from Warsaw 1949 births Living people Indiana University School of Medicine faculty Temple University faculty Polish emigrants to the United States