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Macrophages are among the most important inflammatory cells in the synovium of patients with rheumatoid arthritis, according to research discussed at the Canadian Arthritis Research Conference: Research with Impact.
Work conducted as part of the Accelerating Medicines Partnership (AMP) Rheumatoid Arthritis and Systemic Lupus Erythematosus (RA/SLE) Network suggests that not only do macrophages play an inflammatory role, but there may also be a subset of macrophages that have a predominantly anti-inflammatory effect.
“These are cells that are really activated and can produce a lot of proinflammatory cytokines, including TNF [tumor necrosis factor],” said Jennifer Howitt Anolik, MD, PhD, associate professor of medicine at the University of Rochester (N.Y.) and cochair of the AMP RA/SLE Network.
“In addition to inflammatory mediators there’s an anti-inflammatory population which may control the disease,” she added, at the virtual meeting, which was sponsored by The Arthritis Society, the Canadian Rheumatology Association, and Canada’s Institute of Health and Arthritis.
There are up to 15 different populations of macrophages found so far as part of a project by Fan Zhang of Brigham and Women’s Hospital and Harvard Medical School in Boston, Dr. Anolik revealed. Of these, three have been shown to be proinflammatory and five have been shown to be anti-inflammatory – including one of particular interest that expresses MERTK, which recent work suggests are lacking in people with RA, compared with a control population of people with osteoarthritis (OA).
Clearly, Dr. Anolik said, there is “lots more work to do to understand how those anti-inflammatory monocytes might work, understand the relationship to treatment response and treatment failure, and how to target them.”
AMP RA/SLE Network: Examining RA synovial tissue
What’s unique about the AMP’s work is that it is involving single-cell analytics in which individual cells derived from patients with RA are subjected to an array of RNA sequencing and molecular classification methods.
“If we’re able to define the cells that are driving the disease at the tissue level, this may lead to better therapeutics and more of like a precision medicine approach,” Dr. Anolik said. An important feature of the AMP’s work is that it is based on the use of existing and thus “very informative cohorts” for whom we know a lot about disease characteristics, she said.
The AMP RA/SLE Network officially formed in 2014 and is a public–private partnership between the National Institutes of Health, the Food and Drug Administration, several biopharmaceutical companies, and nonprofit organizations. The task was to try to accelerate discoveries that would lead to better patient care.
“The initial phase [Research Phase 0], was really about developing the procedures in a standardized way,” Dr. Anolik said. “Because we’re looking at patient joint tissue samples, we needed to access that tissue and that required developing needle biopsy approaches.” Synovial biopsy had been pioneered in the United Kingdom and become fairly standard to perform, she added, but this was not an approach that was routinely being used in the United States at the time.
In the next step, Research Phase I, researchers looked at the expression profiles of RA synovial cells in a small group of patients. In all, around 5,000 cells from the joints of up to 20 patients with RA were analyzed. What was apparent was that while there were fibroblasts, monocytes, T cells, and B cells all present to some degree, there was substantial heterogeneity among those subtypes.
“Within all the different immune cells and stromal cells, we found 18 different populations overall,” Dr. Anolik said, giving some of the top-level findings. Both single-cell RNA sequencing and mass cytometry revealed that there were greatly (16-fold) increased numbers of a population of sublining fibroblasts and a 3.3-fold increase in interleukin-1-beta-expressing proinflammatory monocytes. There was a threefold increase in a subset of B cells expressing CD11/T-bet, and a 2.4-fold increase in certain peripheral T cells.
“Interestingly, we were able to pinpoint which cells are making which kinds of inflammatory mediators like inflammatory cytokines,” Dr. Anolik said. Notably, one of the fibroblast populations and one of the B cells were prominent producers of interleukin-6.
The AMP RA/SLE Network is now in Research Phase II, looking at much greater numbers of cells (>5,000) in more than 100 samples from individual patients. It’s a “very comprehensive, big data look at RA,” according to Dr. Anolik.
Research Phase II will also see more rigorous groups of patients being examined, including those who have not had any or much exposure to disease-modifying antirheumatic drugs and those who have inadequately responded to methotrexate or anti-TNF drugs.
Recent AMP RA/SLE Network findings
Recent work by the AMP RA/SLE Network has shown that stromal fibroblasts can become highly inflammatory in RA.
“What’s becoming clear is that these are more than just lining of the joint or structure of the joint, they actually play an active role in the disease,” Dr. Anolik said.
There is a lot of diversity in these fibroblasts but they broadly fall into lining or sublining subtypes. Those that are proinflammatory tend to express markers such as HLA-DR and CD90, and one that is of notable interest is a subgroup of sublining fibroblasts that express Notch3. Indeed, it has been shown that the higher the number of Notch3-expressing fibroblasts there are in the joint, the greater the level of inflammation. Also, mice lacking Notch3 seem to get less arthritis than those with Notch3. This makes Notch3 an interesting potential target that no one had thought of before.
Dr. Anolik noted that some evolving concepts about T cells include evidence showing CD8-postive T cells are more abundant in the joint tissue than previously thought and, together with natural killer (NK) cells, are an important producer of interferon-gamma.
“There are some very interesting CD4 T-cell populations, including an expansion of T peripheral helper cells that may be very important in driving B-cell activation,” Dr. Anolik said. There are also many other clusters of T cells and NK cells that have unknown roles.
Over the past years, Dr. Anolik’s research had focused on the role B cells play in autoimmune disease, and one of the cells of interest are known as age-related B cells, or ABCs. High percentages of ABCs have been found in the RA synovium, and these seem to be related to disease activity as measured by the Disease Activity Score in 28 joints (DAS28). These cells also seem to cluster with some of the T helper cell populations found in the joint. Another interesting target could be B cells expressing a transcription factor known as T-bet. Work in mice suggests that the absence of T-bet B cells could be associated with reduced levels of arthritis.
“One of the things that we’re really interested in about B cells, in addition to their production of autoantibodies, is that they may be important for some of the structural damage that occurs with rheumatoid arthritis,” she said.
T-bet B cells seem to have an effect on both osteoclasts and osteoblasts – activating one while inhibiting the other to have a negative effect on bone overall, she explained. However, knocking out T-bet seems to resolve this, again suggesting that T-bet B cells may be another interesting subpopulation to target.
“Overall, the AMP has been a really interesting approach. This is a massive data set. We are putting the data together now to publish, and it will be available in the public domain,” Dr. Anolik said.
Members of the AMP RA/SLE Network include: AbbVie, the Arthritis Foundation, Bristol‐Myers Squibb, the Foundation for the NIH, the Lupus Foundation of America, the Lupus Research Alliance, Merck Sharp & Dohme, the National Institute of Allergy and Infectious Diseases, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, Pfizer, the Rheumatology Research Foundation, Sanofi, and Takeda Pharmaceuticals International.
Dr. Anolik had no disclosures.
Macrophages are among the most important inflammatory cells in the synovium of patients with rheumatoid arthritis, according to research discussed at the Canadian Arthritis Research Conference: Research with Impact.
Work conducted as part of the Accelerating Medicines Partnership (AMP) Rheumatoid Arthritis and Systemic Lupus Erythematosus (RA/SLE) Network suggests that not only do macrophages play an inflammatory role, but there may also be a subset of macrophages that have a predominantly anti-inflammatory effect.
“These are cells that are really activated and can produce a lot of proinflammatory cytokines, including TNF [tumor necrosis factor],” said Jennifer Howitt Anolik, MD, PhD, associate professor of medicine at the University of Rochester (N.Y.) and cochair of the AMP RA/SLE Network.
“In addition to inflammatory mediators there’s an anti-inflammatory population which may control the disease,” she added, at the virtual meeting, which was sponsored by The Arthritis Society, the Canadian Rheumatology Association, and Canada’s Institute of Health and Arthritis.
There are up to 15 different populations of macrophages found so far as part of a project by Fan Zhang of Brigham and Women’s Hospital and Harvard Medical School in Boston, Dr. Anolik revealed. Of these, three have been shown to be proinflammatory and five have been shown to be anti-inflammatory – including one of particular interest that expresses MERTK, which recent work suggests are lacking in people with RA, compared with a control population of people with osteoarthritis (OA).
Clearly, Dr. Anolik said, there is “lots more work to do to understand how those anti-inflammatory monocytes might work, understand the relationship to treatment response and treatment failure, and how to target them.”
AMP RA/SLE Network: Examining RA synovial tissue
What’s unique about the AMP’s work is that it is involving single-cell analytics in which individual cells derived from patients with RA are subjected to an array of RNA sequencing and molecular classification methods.
“If we’re able to define the cells that are driving the disease at the tissue level, this may lead to better therapeutics and more of like a precision medicine approach,” Dr. Anolik said. An important feature of the AMP’s work is that it is based on the use of existing and thus “very informative cohorts” for whom we know a lot about disease characteristics, she said.
The AMP RA/SLE Network officially formed in 2014 and is a public–private partnership between the National Institutes of Health, the Food and Drug Administration, several biopharmaceutical companies, and nonprofit organizations. The task was to try to accelerate discoveries that would lead to better patient care.
“The initial phase [Research Phase 0], was really about developing the procedures in a standardized way,” Dr. Anolik said. “Because we’re looking at patient joint tissue samples, we needed to access that tissue and that required developing needle biopsy approaches.” Synovial biopsy had been pioneered in the United Kingdom and become fairly standard to perform, she added, but this was not an approach that was routinely being used in the United States at the time.
In the next step, Research Phase I, researchers looked at the expression profiles of RA synovial cells in a small group of patients. In all, around 5,000 cells from the joints of up to 20 patients with RA were analyzed. What was apparent was that while there were fibroblasts, monocytes, T cells, and B cells all present to some degree, there was substantial heterogeneity among those subtypes.
“Within all the different immune cells and stromal cells, we found 18 different populations overall,” Dr. Anolik said, giving some of the top-level findings. Both single-cell RNA sequencing and mass cytometry revealed that there were greatly (16-fold) increased numbers of a population of sublining fibroblasts and a 3.3-fold increase in interleukin-1-beta-expressing proinflammatory monocytes. There was a threefold increase in a subset of B cells expressing CD11/T-bet, and a 2.4-fold increase in certain peripheral T cells.
“Interestingly, we were able to pinpoint which cells are making which kinds of inflammatory mediators like inflammatory cytokines,” Dr. Anolik said. Notably, one of the fibroblast populations and one of the B cells were prominent producers of interleukin-6.
The AMP RA/SLE Network is now in Research Phase II, looking at much greater numbers of cells (>5,000) in more than 100 samples from individual patients. It’s a “very comprehensive, big data look at RA,” according to Dr. Anolik.
Research Phase II will also see more rigorous groups of patients being examined, including those who have not had any or much exposure to disease-modifying antirheumatic drugs and those who have inadequately responded to methotrexate or anti-TNF drugs.
Recent AMP RA/SLE Network findings
Recent work by the AMP RA/SLE Network has shown that stromal fibroblasts can become highly inflammatory in RA.
“What’s becoming clear is that these are more than just lining of the joint or structure of the joint, they actually play an active role in the disease,” Dr. Anolik said.
There is a lot of diversity in these fibroblasts but they broadly fall into lining or sublining subtypes. Those that are proinflammatory tend to express markers such as HLA-DR and CD90, and one that is of notable interest is a subgroup of sublining fibroblasts that express Notch3. Indeed, it has been shown that the higher the number of Notch3-expressing fibroblasts there are in the joint, the greater the level of inflammation. Also, mice lacking Notch3 seem to get less arthritis than those with Notch3. This makes Notch3 an interesting potential target that no one had thought of before.
Dr. Anolik noted that some evolving concepts about T cells include evidence showing CD8-postive T cells are more abundant in the joint tissue than previously thought and, together with natural killer (NK) cells, are an important producer of interferon-gamma.
“There are some very interesting CD4 T-cell populations, including an expansion of T peripheral helper cells that may be very important in driving B-cell activation,” Dr. Anolik said. There are also many other clusters of T cells and NK cells that have unknown roles.
Over the past years, Dr. Anolik’s research had focused on the role B cells play in autoimmune disease, and one of the cells of interest are known as age-related B cells, or ABCs. High percentages of ABCs have been found in the RA synovium, and these seem to be related to disease activity as measured by the Disease Activity Score in 28 joints (DAS28). These cells also seem to cluster with some of the T helper cell populations found in the joint. Another interesting target could be B cells expressing a transcription factor known as T-bet. Work in mice suggests that the absence of T-bet B cells could be associated with reduced levels of arthritis.
“One of the things that we’re really interested in about B cells, in addition to their production of autoantibodies, is that they may be important for some of the structural damage that occurs with rheumatoid arthritis,” she said.
T-bet B cells seem to have an effect on both osteoclasts and osteoblasts – activating one while inhibiting the other to have a negative effect on bone overall, she explained. However, knocking out T-bet seems to resolve this, again suggesting that T-bet B cells may be another interesting subpopulation to target.
“Overall, the AMP has been a really interesting approach. This is a massive data set. We are putting the data together now to publish, and it will be available in the public domain,” Dr. Anolik said.
Members of the AMP RA/SLE Network include: AbbVie, the Arthritis Foundation, Bristol‐Myers Squibb, the Foundation for the NIH, the Lupus Foundation of America, the Lupus Research Alliance, Merck Sharp & Dohme, the National Institute of Allergy and Infectious Diseases, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, Pfizer, the Rheumatology Research Foundation, Sanofi, and Takeda Pharmaceuticals International.
Dr. Anolik had no disclosures.
Macrophages are among the most important inflammatory cells in the synovium of patients with rheumatoid arthritis, according to research discussed at the Canadian Arthritis Research Conference: Research with Impact.
Work conducted as part of the Accelerating Medicines Partnership (AMP) Rheumatoid Arthritis and Systemic Lupus Erythematosus (RA/SLE) Network suggests that not only do macrophages play an inflammatory role, but there may also be a subset of macrophages that have a predominantly anti-inflammatory effect.
“These are cells that are really activated and can produce a lot of proinflammatory cytokines, including TNF [tumor necrosis factor],” said Jennifer Howitt Anolik, MD, PhD, associate professor of medicine at the University of Rochester (N.Y.) and cochair of the AMP RA/SLE Network.
“In addition to inflammatory mediators there’s an anti-inflammatory population which may control the disease,” she added, at the virtual meeting, which was sponsored by The Arthritis Society, the Canadian Rheumatology Association, and Canada’s Institute of Health and Arthritis.
There are up to 15 different populations of macrophages found so far as part of a project by Fan Zhang of Brigham and Women’s Hospital and Harvard Medical School in Boston, Dr. Anolik revealed. Of these, three have been shown to be proinflammatory and five have been shown to be anti-inflammatory – including one of particular interest that expresses MERTK, which recent work suggests are lacking in people with RA, compared with a control population of people with osteoarthritis (OA).
Clearly, Dr. Anolik said, there is “lots more work to do to understand how those anti-inflammatory monocytes might work, understand the relationship to treatment response and treatment failure, and how to target them.”
AMP RA/SLE Network: Examining RA synovial tissue
What’s unique about the AMP’s work is that it is involving single-cell analytics in which individual cells derived from patients with RA are subjected to an array of RNA sequencing and molecular classification methods.
“If we’re able to define the cells that are driving the disease at the tissue level, this may lead to better therapeutics and more of like a precision medicine approach,” Dr. Anolik said. An important feature of the AMP’s work is that it is based on the use of existing and thus “very informative cohorts” for whom we know a lot about disease characteristics, she said.
The AMP RA/SLE Network officially formed in 2014 and is a public–private partnership between the National Institutes of Health, the Food and Drug Administration, several biopharmaceutical companies, and nonprofit organizations. The task was to try to accelerate discoveries that would lead to better patient care.
“The initial phase [Research Phase 0], was really about developing the procedures in a standardized way,” Dr. Anolik said. “Because we’re looking at patient joint tissue samples, we needed to access that tissue and that required developing needle biopsy approaches.” Synovial biopsy had been pioneered in the United Kingdom and become fairly standard to perform, she added, but this was not an approach that was routinely being used in the United States at the time.
In the next step, Research Phase I, researchers looked at the expression profiles of RA synovial cells in a small group of patients. In all, around 5,000 cells from the joints of up to 20 patients with RA were analyzed. What was apparent was that while there were fibroblasts, monocytes, T cells, and B cells all present to some degree, there was substantial heterogeneity among those subtypes.
“Within all the different immune cells and stromal cells, we found 18 different populations overall,” Dr. Anolik said, giving some of the top-level findings. Both single-cell RNA sequencing and mass cytometry revealed that there were greatly (16-fold) increased numbers of a population of sublining fibroblasts and a 3.3-fold increase in interleukin-1-beta-expressing proinflammatory monocytes. There was a threefold increase in a subset of B cells expressing CD11/T-bet, and a 2.4-fold increase in certain peripheral T cells.
“Interestingly, we were able to pinpoint which cells are making which kinds of inflammatory mediators like inflammatory cytokines,” Dr. Anolik said. Notably, one of the fibroblast populations and one of the B cells were prominent producers of interleukin-6.
The AMP RA/SLE Network is now in Research Phase II, looking at much greater numbers of cells (>5,000) in more than 100 samples from individual patients. It’s a “very comprehensive, big data look at RA,” according to Dr. Anolik.
Research Phase II will also see more rigorous groups of patients being examined, including those who have not had any or much exposure to disease-modifying antirheumatic drugs and those who have inadequately responded to methotrexate or anti-TNF drugs.
Recent AMP RA/SLE Network findings
Recent work by the AMP RA/SLE Network has shown that stromal fibroblasts can become highly inflammatory in RA.
“What’s becoming clear is that these are more than just lining of the joint or structure of the joint, they actually play an active role in the disease,” Dr. Anolik said.
There is a lot of diversity in these fibroblasts but they broadly fall into lining or sublining subtypes. Those that are proinflammatory tend to express markers such as HLA-DR and CD90, and one that is of notable interest is a subgroup of sublining fibroblasts that express Notch3. Indeed, it has been shown that the higher the number of Notch3-expressing fibroblasts there are in the joint, the greater the level of inflammation. Also, mice lacking Notch3 seem to get less arthritis than those with Notch3. This makes Notch3 an interesting potential target that no one had thought of before.
Dr. Anolik noted that some evolving concepts about T cells include evidence showing CD8-postive T cells are more abundant in the joint tissue than previously thought and, together with natural killer (NK) cells, are an important producer of interferon-gamma.
“There are some very interesting CD4 T-cell populations, including an expansion of T peripheral helper cells that may be very important in driving B-cell activation,” Dr. Anolik said. There are also many other clusters of T cells and NK cells that have unknown roles.
Over the past years, Dr. Anolik’s research had focused on the role B cells play in autoimmune disease, and one of the cells of interest are known as age-related B cells, or ABCs. High percentages of ABCs have been found in the RA synovium, and these seem to be related to disease activity as measured by the Disease Activity Score in 28 joints (DAS28). These cells also seem to cluster with some of the T helper cell populations found in the joint. Another interesting target could be B cells expressing a transcription factor known as T-bet. Work in mice suggests that the absence of T-bet B cells could be associated with reduced levels of arthritis.
“One of the things that we’re really interested in about B cells, in addition to their production of autoantibodies, is that they may be important for some of the structural damage that occurs with rheumatoid arthritis,” she said.
T-bet B cells seem to have an effect on both osteoclasts and osteoblasts – activating one while inhibiting the other to have a negative effect on bone overall, she explained. However, knocking out T-bet seems to resolve this, again suggesting that T-bet B cells may be another interesting subpopulation to target.
“Overall, the AMP has been a really interesting approach. This is a massive data set. We are putting the data together now to publish, and it will be available in the public domain,” Dr. Anolik said.
Members of the AMP RA/SLE Network include: AbbVie, the Arthritis Foundation, Bristol‐Myers Squibb, the Foundation for the NIH, the Lupus Foundation of America, the Lupus Research Alliance, Merck Sharp & Dohme, the National Institute of Allergy and Infectious Diseases, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, Pfizer, the Rheumatology Research Foundation, Sanofi, and Takeda Pharmaceuticals International.
Dr. Anolik had no disclosures.
FROM CARC 2021