GO:1901646 negative regulation of synoviocyte proliferation: Rheumatoid Arthritis Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1901646 (negative regulation of synoviocyte proliferation) describes any biological process that stops, prevents, or reduces the frequency, rate, or extent of synoviocyte proliferation.
• Fibroblast-like synoviocytes (FLS) are the primary synoviocyte subtype whose excessive proliferation drives rheumatoid arthritis (RA) synovial hyperplasia and joint destruction.
• Multiple microRNAs (miR-135a-5p, miR-216a-3p, miR-98) and proteins (SFRP1, KLF7, GRK2, SAV1) act as negative regulators of FLS proliferation.
• Dysregulation of negative regulators such as GRK2-mediated SAV1 degradation or KLF7 inhibition promotes FLS hyperplasia and inflammation.
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of candidate negative regulators in synoviocytes.
• Targeting negative regulatory pathways (e.g., miR-135a-5p/STAT6, miR-216a-3p/DUSP5) represents a therapeutic strategy to suppress RA synovial hyperplasia.
Description
GO:1901646, negative regulation of synoviocyte proliferation, is a Gene Ontology biological process term defined as any process that stops, prevents, or reduces the frequency, rate, or extent of synoviocyte proliferation. Synoviocytes are the resident cells of the synovial membrane, and their abnormal proliferation is a hallmark of inflammatory joint diseases, particularly rheumatoid arthritis (RA). In RA, fibroblast-like synoviocytes (FLS) acquire an aggressive, tumor-like phenotype characterized by increased proliferation, migration, and invasion, leading to synovial hyperplasia and cartilage destruction. Understanding the molecular mechanisms that negatively regulate synoviocyte proliferation is therefore critical for identifying therapeutic targets and biomarkers. This article synthesizes published evidence on the genes, pathways, and experimental models used to study GO:1901646, with a focus on RA-associated FLS biology.
negative regulation of synoviocyte proliferation At A Glance
| GO ID | GO:1901646 |
|---|---|
| GO term | negative regulation of synoviocyte proliferation |
| Ontology | biological_process |
| Synonym | down regulation of synoviocyte proliferation, down-regulation of synoviocyte proliferation, downregulation of synoviocyte proliferation, inhibition of synoviocyte proliferation |
| Major function | Suppression of synoviocyte proliferation, preventing synovial hyperplasia |
| Definition | Any process that stops, prevents or reduces the frequency, rate or extent of synoviocyte proliferation. |
| Related cell type | Fibroblast-like synoviocytes (FLS), synovial lining cells |
| Associated disease | Rheumatoid arthritis (RA), inflammatory joint diseases |
| Key negative regulators | miR-135a-5p, miR-216a-3p, miR-98, SFRP1, KLF7, GRK2/SAV1 axis |
What Is GO:1901646?
GO:1901646 (negative regulation of synoviocyte proliferation) refers to any biological process that stops, prevents, or reduces the frequency, rate, or extent of synoviocyte proliferation. This includes molecular signals, such as microRNAs, proteins, and signaling pathways, that suppress the division of synoviocytes, particularly fibroblast-like synoviocytes in the synovial lining. The term is a child of negative regulation of cell proliferation and is specific to synoviocytes, distinguishing it from general anti-proliferative processes.
Why Is negative regulation of synoviocyte proliferation Important in Cell Biology?
Negative regulation of synoviocyte proliferation is essential for maintaining synovial homeostasis and preventing pathological synovial hyperplasia. In rheumatoid arthritis, loss of negative regulatory control leads to excessive FLS proliferation, chronic inflammation, and joint destruction. Elucidating the mechanisms of GO:1901646 provides insights into RA pathogenesis and identifies potential therapeutic targets, such as microRNAs and signaling proteins that can be harnessed to suppress FLS proliferation.
• Prevents synovial hyperplasia, a hallmark of rheumatoid arthritis.
• Controls FLS proliferation, migration, and invasion in inflammatory arthritis.
• MicroRNAs (miR-135a-5p, miR-216a-3p, miR-98) negatively regulate FLS proliferation and induce apoptosis.
• SFRP1 negatively modulates pyroptosis and proliferation in FLS.
• GRK2-mediated degradation of SAV1 initiates FLS hyperplasia, highlighting the importance of negative regulation.
• KLF7 inhibition attenuates FLS proliferation and inflammation via NF-κB and MAPK pathways.
• YTHDC1 regulates FLS migration, invasion, proliferation, and apoptosis.
• LncRNA FOXD2-AS1 promotes FLS proliferation by regulating miR-331-3p/PIAS3, indicating competing endogenous RNA networks.
• Targeting negative regulators offers therapeutic strategies for RA.
• Provides mechanistic biomarkers for RA diagnosis and prognosis.
What Happens During negative regulation of synoviocyte proliferation?
MicroRNA-mediated suppression of FLS proliferation
In simple terms: Small RNA molecules can put the brakes on synoviocyte growth.
MicroRNAs such as miR-135a-5p and miR-216a-3p negatively regulate FLS proliferation by targeting specific mRNAs. miR-135a-5p down-regulates STAT6, inhibiting proliferation and inducing apoptosis in RA FLS. miR-216a-3p inhibits proliferation and invasion by targeting dual-specificity phosphatase 5 (DUSP5). Down-regulation of miR-98 promotes apoptosis of TNF-α stimulated human FLS via up-regulating IL-10. These microRNAs act as negative regulators of synoviocyte proliferation, contributing to GO:1901646.
Protein-mediated inhibition of FLS proliferation
In simple terms: Certain proteins can directly stop synoviocytes from dividing.
SFRP1 negatively modulates pyroptosis and proliferation of FLS in RA. Inhibition of Kruppel-like factor 7 (KLF7) attenuates cell proliferation and inflammation of FLS through NF-κB and MAPK signaling pathways. GRK2-mediated degradation of SAV1 initiates hyperplasia of FLS in RA, indicating that loss of SAV1 removes a negative regulatory brake. These proteins are key effectors of GO:1901646.
Long non-coding RNA and competing endogenous RNA networks
In simple terms: Long non-coding RNAs can sponge microRNAs to influence synoviocyte growth.
LncRNA FOXD2-AS1 promotes cell proliferation and invasion of FLS by regulating the miR-331-3p/PIAS3 pathway in RA. This indicates that lncRNAs can act as competing endogenous RNAs (ceRNAs) to modulate the availability of microRNAs that would otherwise negatively regulate proliferation. Thus, dysregulation of ceRNA networks can impair GO:1901646.
RNA modification and splicing regulation
In simple terms: Chemical marks on RNA can affect how synoviocytes behave.
YTHDC1, an m6A reader, regulates the migration, invasion, proliferation, and apoptosis of rheumatoid FLS. This suggests that epitranscriptomic modifications influence the negative regulation of synoviocyte proliferation, adding another layer of control to GO:1901646.
Signaling pathways involved in negative regulation
In simple terms: Cellular communication lines can either promote or suppress synoviocyte division.
NF-κB and MAPK signaling pathways are involved in FLS proliferation and inflammation; inhibition of KLF7 attenuates these pathways. GRK2-mediated SAV1 degradation affects Hippo signaling, which controls organ size and proliferation. These pathways integrate signals that ultimately determine the proliferative rate of synoviocytes, and their negative regulation is central to GO:1901646.
Key Genes Involved in GO:1901646 negative regulation of synoviocyte proliferation
The following genes and non-coding RNAs have been experimentally implicated in the negative regulation of synoviocyte proliferation (GO:1901646) in rheumatoid arthritis and related inflammatory joint diseases.
| Gene | Major Role | Research Relevance |
|---|---|---|
| GRK2 | Kinase that phosphorylates and promotes degradation of SAV1 | GRK2-mediated SAV1 degradation initiates FLS hyperplasia in RA |
| SAV1 | Scaffold protein in Hippo pathway; negatively regulates proliferation | Its degradation by GRK2 removes negative regulation of FLS proliferation |
| STAT6 | Transcription factor; target of miR-135a-5p | miR-135a-5p down-regulates STAT6 to inhibit FLS proliferation and induce apoptosis |
| SFRP1 | Secreted frizzled-related protein; modulates Wnt signaling | Negatively modulates pyroptosis and proliferation of FLS in RA |
| FOXD2-AS1 | Long non-coding RNA; ceRNA for miR-331-3p | Promotes FLS proliferation and invasion via miR-331-3p/PIAS3 axis |
| PIAS3 | Protein inhibitor of activated STAT3; target of miR-331-3p | Part of FOXD2-AS1/miR-331-3p/PIAS3 pathway in FLS |
| miR-216a-3p | MicroRNA; targets DUSP5 | Inhibits proliferation and invasion of FLS |
| DUSP5 | Dual-specificity phosphatase 5; target of miR-216a-3p | Its targeting by miR-216a-3p suppresses FLS proliferation |
| YTHDC1 | m6A RNA reader; regulates RNA metabolism | Regulates migration, invasion, proliferation, and apoptosis of rheumatoid FLS |
| miR-98 | MicroRNA; down-regulation promotes apoptosis | Down-regulation of miR-98 promotes apoptosis of TNF-α stimulated FLS via IL-10 |
| IL-10 | Anti-inflammatory cytokine; up-regulated by miR-98 down-regulation | Mediates apoptosis of FLS |
| KLF7 | Kruppel-like transcription factor; promotes proliferation and inflammation | Inhibition attenuates FLS proliferation and inflammation via NF-κB and MAPK |
| NF-κB | Transcription factor; pro-inflammatory and pro-proliferative | Pathway affected by KLF7 inhibition in FLS |
| MAPK | Mitogen-activated protein kinase signaling cascade | Pathway affected by KLF7 inhibition in FLS |
| miR-135a-5p | MicroRNA; targets STAT6 | Inhibits proliferation and induces apoptosis of FLS |
| miR-331-3p | MicroRNA; targets PIAS3 | Regulated by lncRNA FOXD2-AS1 in FLS |
How Is negative regulation of synoviocyte proliferation Regulated?
The negative regulation of synoviocyte proliferation (GO:1901646) is controlled by multiple layers of regulation. MicroRNAs such as miR-135a-5p, miR-216a-3p, and miR-98 directly target mRNAs encoding pro-proliferative or anti-apoptotic proteins, thereby suppressing FLS proliferation. Protein kinases like GRK2 can phosphorylate and promote degradation of SAV1, a Hippo pathway scaffold, thereby removing a negative regulatory brake on FLS proliferation. Transcription factors such as KLF7 and STAT6 modulate the expression of genes involved in proliferation and inflammation. Additionally, long non-coding RNAs like FOXD2-AS1 act as competing endogenous RNAs to sequester microRNAs, indirectly affecting proliferation. Epitranscriptomic regulators such as YTHDC1 influence RNA stability and translation, adding another regulatory layer. These diverse mechanisms converge to determine the proliferative rate of synoviocytes, and their dysregulation contributes to RA pathogenesis.
negative regulation of synoviocyte proliferation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| GRK2 | Rheumatoid arthritis; FLS hyperplasia | Knockout or overexpression in RA FLS cell lines; collagen-induced arthritis mouse model |
| STAT6 | Rheumatoid arthritis; FLS proliferation and apoptosis | miR-135a-5p mimic/inhibitor in FLS; STAT6 knockout |
| SFRP1 | Rheumatoid arthritis; pyroptosis and proliferation | SFRP1 overexpression or knockdown in FLS |
| KLF7 | Rheumatoid arthritis; inflammation and proliferation | KLF7 siRNA or overexpression in FLS; NF-κB/MAPK inhibitors |
| YTHDC1 | Rheumatoid arthritis; FLS migration and invasion | YTHDC1 knockdown or overexpression in FLS |
Rheumatoid arthritis
Rheumatoid arthritis (RA) is the primary disease associated with dysregulation of GO:1901646. Excessive proliferation of fibroblast-like synoviocytes (FLS) leads to synovial hyperplasia, pannus formation, and joint destruction. Negative regulators such as miR-135a-5p, miR-216a-3p, and SFRP1 are often down-regulated in RA, contributing to FLS hyperproliferation. GRK2-mediated degradation of SAV1 initiates FLS hyperplasia, highlighting the importance of negative regulatory pathways in RA. Targeting these pathways may provide therapeutic benefits.
Inflammatory joint diseases
Beyond RA, other inflammatory joint diseases may involve altered negative regulation of synoviocyte proliferation. The shared feature is chronic inflammation and synovial hyperplasia, where loss of negative regulators such as KLF7 or microRNAs promotes FLS proliferation. Understanding GO:1901646 in these contexts could reveal common therapeutic targets.
Cancer-like behavior of FLS
FLS in RA exhibit tumor-like properties, including increased proliferation, migration, and invasion. Negative regulators of proliferation, such as miR-216a-3p and miR-135a-5p, act as tumor suppressors in this context. Their loss contributes to the aggressive phenotype of FLS, drawing parallels to cancer biology and suggesting that strategies used in oncology might be applicable to RA.
From negative regulation of synoviocyte proliferation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene increase FLS proliferation? | CRISPR knockout of the gene in RA FLS cell lines (e.g., MH7A, SW982) |
| Does a specific point mutation in a negative regulator affect its function? | CRISPR point mutation (e.g., kinase-dead GRK2) in FLS |
| Does overexpression of a negative regulator suppress FLS proliferation? | Lentiviral overexpression of miR-135a-5p or SFRP1 in FLS |
| Does a tagged knock-in reveal protein localization and interactions? | CRISPR knock-in of FLAG or GFP tag into endogenous locus in FLS |
| Does modulation of a lncRNA affect FLS proliferation? | CRISPR interference (CRISPRi) or knockout of FOXD2-AS1 in FLS |
| Does epitranscriptomic regulation affect FLS phenotype? | CRISPR knockout of YTHDC1 in FLS followed by proliferation assays |
How to Study the negative regulation of synoviocyte proliferation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| EdU incorporation assay | DNA synthesis and cell proliferation | Quantify FLS proliferation after gene knockout or overexpression |
| MTT/CCK-8 assay | Metabolic activity and cell viability | Assess growth inhibition by negative regulators |
| Flow cytometry (Annexin V/PI) | Apoptosis and cell death | Determine if negative regulators induce apoptosis |
| Transwell migration assay | Cell migration capacity | Evaluate invasive phenotype of FLS |
| Western blot | Protein expression and phosphorylation | Validate signaling pathways (NF-κB, MAPK) |
| qRT-PCR | mRNA and microRNA expression levels | Measure target gene expression after manipulation |
| Luciferase reporter assay | MicroRNA-target interaction | Confirm direct targeting of STAT6 by miR-135a-5p |
| Immunohistochemistry | Protein localization in synovial tissue | Assess expression in RA patient samples |
Proliferation assays
Cell proliferation can be measured using EdU incorporation, MTT, or CCK-8 assays in FLS after genetic manipulation. These assays quantify the rate of DNA synthesis or metabolic activity, providing a direct readout of synoviocyte proliferation.
Apoptosis assays
Flow cytometry with Annexin V/PI staining or caspase activity assays can determine whether negative regulators induce apoptosis in FLS. For example, miR-135a-5p induces apoptosis in RA FLS, and down-regulation of miR-98 promotes apoptosis.
Migration and invasion assays
Transwell migration and Matrigel invasion assays assess the invasive phenotype of FLS, which is often co-regulated with proliferation. miR-216a-3p inhibits both proliferation and invasion, and YTHDC1 regulates migration and invasion.
Molecular signaling analysis
Western blotting, qRT-PCR, and luciferase reporter assays are used to validate microRNA targets and signaling pathways. For instance, STAT6 is a validated target of miR-135a-5p, and KLF7 inhibition affects NF-κB and MAPK pathways.
How CRISPR Can Be Used to Study GO:1901646 negative regulation of synoviocyte proliferation
Knockout
CRISPR knockout of candidate negative regulators (e.g., SAV1, SFRP1, KLF7) in FLS cell lines can determine whether their loss increases proliferation. For example, knockout of SAV1 would mimic GRK2-mediated degradation and potentially enhance FLS hyperplasia. Knockout of KLF7 would test its role in proliferation and inflammation.
Point Mutation
CRISPR point mutation can introduce specific amino acid changes to dissect functional domains. For instance, mutating the kinase domain of GRK2 could prevent SAV1 phosphorylation and degradation, thereby preserving negative regulation of FLS proliferation. Similarly, point mutations in STAT6 could affect its DNA-binding or transactivation capacity.
Knock-in
CRISPR knock-in of tags (e.g., FLAG, GFP) or reporter genes into endogenous loci allows real-time tracking of protein expression and localization. Knocking in a luciferase reporter under the control of a negative regulator promoter could enable high-throughput screening for compounds that induce its expression.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression can elevate levels of negative regulators such as miR-135a-5p, miR-216a-3p, or SFRP1 to suppress FLS proliferation. Overexpression of miR-135a-5p inhibits proliferation and induces apoptosis, while SFRP1 overexpression negatively modulates pyroptosis and proliferation.
How EDITGENE Supports negative regulation of synoviocyte proliferation Research
Researchers studying negative regulation of synoviocyte proliferation-related genes often need to determine whether a candidate gene is causally involved in suppressing FLS proliferation or is merely a bystander. EDITGENE provides comprehensive CRISPR-based services to enable such causal studies in synoviocyte models.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of synoviocyte proliferation research.
Frequently Asked Questions About negative regulation of synoviocyte proliferation
What is GO:1901646?
GO:1901646 is the Gene Ontology term for negative regulation of synoviocyte proliferation, defined as any process that stops, prevents, or reduces the frequency, rate, or extent of synoviocyte proliferation.
What genes are involved in negative regulation of synoviocyte proliferation?
Key genes include GRK2, SAV1, STAT6, SFRP1, FOXD2-AS1, PIAS3, miR-216a-3p, DUSP5, YTHDC1, miR-98, IL-10, KLF7, miR-135a-5p, and miR-331-3p.
How is synoviocyte proliferation negatively regulated in rheumatoid arthritis?
It is negatively regulated by microRNAs (e.g., miR-135a-5p, miR-216a-3p), proteins (e.g., SFRP1, KLF7), and signaling pathways (e.g., Hippo, NF-κB, MAPK) that suppress FLS proliferation and induce apoptosis.
What is the role of miR-135a-5p in synoviocyte proliferation?
miR-135a-5p down-regulates STAT6, inhibiting proliferation and inducing apoptosis of fibroblast-like synoviocytes in rheumatoid arthritis.
How does GRK2 affect synoviocyte proliferation?
GRK2 mediates degradation of SAV1, which initiates hyperplasia of fibroblast-like synoviocytes in rheumatoid arthritis, thereby removing a negative regulatory brake on proliferation.
What experimental models are used to study negative regulation of synoviocyte proliferation?
Common models include RA FLS cell lines (MH7A, SW982) with CRISPR knockout, overexpression, or microRNA mimics, as well as collagen-induced arthritis mouse models.
What is the role of SFRP1 in synoviocyte proliferation?
SFRP1 negatively modulates pyroptosis and proliferation of fibroblast-like synoviocytes in rheumatoid arthritis.
How does KLF7 inhibition affect synoviocyte proliferation?
Inhibition of Kruppel-like factor 7 attenuates cell proliferation and inflammation of fibroblast-like synoviocytes through NF-κB and MAPK signaling pathways.
What is the significance of YTHDC1 in synoviocyte biology?
YTHDC1 regulates the migration, invasion, proliferation, and apoptosis of rheumatoid fibroblast-like synoviocytes, implicating m6A RNA modification in synoviocyte function.
Can CRISPR be used to study negative regulation of synoviocyte proliferation?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of candidate genes in synoviocyte proliferation assays.
Conclusion
GO:1901646 (negative regulation of synoviocyte proliferation) is a critical biological process that maintains synovial homeostasis and prevents pathological hyperplasia. Its dysregulation is central to rheumatoid arthritis pathogenesis, where loss of negative regulators such as microRNAs, SFRP1, and KLF7 leads to excessive FLS proliferation and joint destruction. Continued research using CRISPR-based models and multi-omics approaches will further elucidate the mechanisms of this process and identify novel therapeutic targets for RA and related inflammatory joint diseases.
References
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- 2. Liu J et al.. 2022. miR-135a-5p mediated down-regulation of STAT6 inhibits proliferation and induces apoptosis of fibroblast-like synoviocytes in rheumatoid arthritis.. Am J Transl Res 14(5):3092-3103 PMID: 35702088
- 3. Jiang P et al.. 2022. SFRP1 Negatively Modulates Pyroptosis of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis: A Review.. Front Immunol 13:903475 PMID: 35795672
- 4. Zhao Q et al.. 2021. LncRNA FOXD2-AS1 promotes cell proliferation and invasion of fibroblast-like synoviocytes by regulation of miR-331-3p/PIAS3 pathway in rheumatoid arthritis.. Autoimmunity 54(5):254-263 PMID: 34030529
- 5. Ni R et al.. 2023. MiR-216a-3p inhibits the proliferation and invasion of fibroblast-like synoviocytes by targeting dual-specificity phosphatase 5.. Int J Rheum Dis 26(4):699-709 PMID: 36843205
- 6. Feng ZW et al.. 2024. YTHDC1 Regulates the Migration, Invasion, Proliferation, and Apoptosis of Rheumatoid Fibroblast-Like Synoviocytes.. Front Immunol 15:1440398 PMID: 39534605
- 7. Li Z et al.. 2019. Down-regulation of microRNA-98 promoted apoptosis of TNF-α stimulated human fibroblast-like synoviocytes via up-regulating IL-10.. Gene 706:124-130 PMID: 31077735
- 8. Cao J et al.. 2022. Inhibition of Kruppel-like factor 7 attenuates cell proliferation and inflammation of fibroblast-like synoviocytes in rheumatoid arthritis through nuclear factor κB and mitogen-activated protein kinase signaling pathway.. Exp Anim 71(3):356-367 PMID: 35321971
