antibodies targeting col2a1  (Proteintech)

Journal: Frontiers in Bioengineering and Biotechnology

Article Title: pH-responsive Zn 2+ -coordinated gellan gum/γ-polyglutamic acid hydrogel microspheres as functional biomaterials for intra-articular delivery: physicochemical design, smart release, and chondroprotective performance in osteoarthritis

doi: 10.3389/fbioe.2026.1924086

Figure Lengend Snippet: qPCR primer information.

Article Snippet: The sections were subsequently reacted with primary antibodies targeting COL2A1 (Proteintech, 28459-1-AP), MMP13 (Proteintech, 18165-1-AP), p-PI3K (HUABIO, HA721672), and p-AKT (Proteintech, 66444-1-Ig) for 16 h at 4 °C.

Techniques: Sequencing

Journal: Frontiers in Bioengineering and Biotechnology

Article Title: pH-responsive Zn 2+ -coordinated gellan gum/γ-polyglutamic acid hydrogel microspheres as functional biomaterials for intra-articular delivery: physicochemical design, smart release, and chondroprotective performance in osteoarthritis

doi: 10.3389/fbioe.2026.1924086

Figure Lengend Snippet: PGG-Zn@Cur restored matrix metabolic homeostasis in IL-1β-stimulated chondrocytes. (A) Representative immunofluorescence images of COL2A1 in chondrocytes after different treatments. COL2A1 was stained red, and nuclei were counterstained with DAPI. (B) Representative immunofluorescence images of MMP13 in chondrocytes after different treatments. MMP13 was stained green, and nuclei were counterstained with DAPI. (C) Quantitative analysis of relative fluorescence intensity for COL2A1 and MMP13 based on immunofluorescence staining. IL-1β stimulation decreased COL2A1 expression and increased MMP13 accumulation, whereas PGG-Zn@Cur treatment restored COL2A1 fluorescence intensity and suppressed MMP13-positive signals. (D–G) RT-qPCR analysis of cartilage matrix metabolism-related genes, including anabolic markers Col2a1 and Aggrecan, and catabolic markers Mmp13 and Adamts5, in chondrocytes after the indicated treatments. (H) Representative Western blot images of iNOS, COL2A1, MMP13, and ACAN protein expression, together with heatmap-based quantitative analysis of Western blot results across different treatment groups. β-Actin was used as the loading control. ( n = 3, Scale bar: 10 μm *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001; ns: no significant).

Article Snippet: The sections were subsequently reacted with primary antibodies targeting COL2A1 (Proteintech, 28459-1-AP), MMP13 (Proteintech, 18165-1-AP), p-PI3K (HUABIO, HA721672), and p-AKT (Proteintech, 66444-1-Ig) for 16 h at 4 °C.

Techniques: Immunofluorescence, Staining, Analysis, Fluorescence, Expressing, Quantitative RT-PCR, Western Blot, Control

Journal: Frontiers in Bioengineering and Biotechnology

Article Title: pH-responsive Zn 2+ -coordinated gellan gum/γ-polyglutamic acid hydrogel microspheres as functional biomaterials for intra-articular delivery: physicochemical design, smart release, and chondroprotective performance in osteoarthritis

doi: 10.3389/fbioe.2026.1924086

Figure Lengend Snippet: PGG-Zn@Cur attenuated PI3K-AKT activation and apoptosis-associated responses in IL-1β-stimulated chondrocytes. (A) Schematic workflow of RNA sequencing and subsequent experimental validation. (B) Heatmap of representative differentially expressed genes related to cartilage matrix metabolism, inflammation, apoptosis, and PI3K-AKT-associated signaling. (C) Volcano plot showing differentially expressed genes between the indicated groups, with representative genes related to cartilage homeostasis, apoptosis, and PI3K-AKT signaling labeled. (D) GO enrichment analysis of differentially expressed genes, including biological process, cellular component, and molecular function categories. (E) KEGG pathway enrichment analysis, with the PI3K-AKT signaling pathway highlighted as a candidate pathway. (F) Representative immunofluorescence images of p-PI3K, p-AKT, Cl-Caspase3, and COL2A1 in chondrocytes after different treatments. Nuclei were counterstained with DAPI. (G) Quantitative analysis of p-PI3K, p-AKT, Cl-Caspase3, and COL2A1 fluorescence intensity. (H) Representative Western blot images of PI3K-AKT pathway- and apoptosis-related proteins, including p-PI3K, PI3K, p-AKT, AKT, Cleaved-Caspase3, Caspase3, Bax, and BCL2. β-Actin was used as the loading control. (I) Heatmap-based quantitative analysis of Western blot results, summarizing changes in p-PI3K/PI3K, p-AKT/AKT, Cleaved-Caspase3/Caspase3, Bax/β-Actin, and BCL2/β-Actin across different groups. ( n = 3, Scale bar: 10 μm *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001; ns: not significant).

Article Snippet: The sections were subsequently reacted with primary antibodies targeting COL2A1 (Proteintech, 28459-1-AP), MMP13 (Proteintech, 18165-1-AP), p-PI3K (HUABIO, HA721672), and p-AKT (Proteintech, 66444-1-Ig) for 16 h at 4 °C.

Techniques: Activation Assay, RNA Sequencing, Biomarker Discovery, Labeling, Analysis, Immunofluorescence, Fluorescence, Western Blot, Control

Journal: Frontiers in Bioengineering and Biotechnology

Article Title: pH-responsive Zn 2+ -coordinated gellan gum/γ-polyglutamic acid hydrogel microspheres as functional biomaterials for intra-articular delivery: physicochemical design, smart release, and chondroprotective performance in osteoarthritis

doi: 10.3389/fbioe.2026.1924086

Figure Lengend Snippet: PGG-Zn@Cur attenuates OA-associated cartilage degeneration and preserves matrix homeostasis in vivo . (A) Representative Safranin O/Fast Green staining images of knee joint cartilage from the Sham, OA, OA+ PGG-Zn, OA+ Cur, and OA+ PGG-Zn@Cur groups. (B) Representative immunofluorescence images of COL2A1 and MMP13 in articular cartilage from different groups. Nuclei were counterstained with DAPI. (C, D) Quantitative analysis of cartilage degeneration using OARSI scores and modified Mankin’s scores. (E) Quantitative analysis of COL2A1 and MMP13 fluorescence intensity in articular cartilage. ( n = 5 mice per group, Scale bar: 50 μm *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001; ns: not significant).

Article Snippet: The sections were subsequently reacted with primary antibodies targeting COL2A1 (Proteintech, 28459-1-AP), MMP13 (Proteintech, 18165-1-AP), p-PI3K (HUABIO, HA721672), and p-AKT (Proteintech, 66444-1-Ig) for 16 h at 4 °C.

Techniques: In Vivo, Staining, Immunofluorescence, Analysis, Modification, Fluorescence

Journal: Frontiers in Bioengineering and Biotechnology

Article Title: pH-responsive Zn 2+ -coordinated gellan gum/γ-polyglutamic acid hydrogel microspheres as functional biomaterials for intra-articular delivery: physicochemical design, smart release, and chondroprotective performance in osteoarthritis

doi: 10.3389/fbioe.2026.1924086

Figure Lengend Snippet: PGG-Zn@Cur attenuates PI3K-AKT pathway activation and apoptosis-associated cartilage damage in vivo . (A) Representative immunofluorescence images of p-PI3K, p-AKT, and COL2A1 in articular cartilage from the Sham, OA, OA+ PGG-Zn, OA+ Cur, and OA+ PGG-Zn@Cur groups. Nuclei were counterstained with DAPI. (B) Representative TUNEL staining images of articular cartilage from different groups. (C) Quantitative analysis of p-PI3K, p-AKT, and COL2A1 fluorescence intensity in articular cartilage. (D) Quantitative analysis of TUNEL-positive chondrocytes in articular cartilage. ( n = 5 mice per group, Scale bar: 50 μm *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001; ns: not significant).

Article Snippet: The sections were subsequently reacted with primary antibodies targeting COL2A1 (Proteintech, 28459-1-AP), MMP13 (Proteintech, 18165-1-AP), p-PI3K (HUABIO, HA721672), and p-AKT (Proteintech, 66444-1-Ig) for 16 h at 4 °C.

Techniques: Activation Assay, In Vivo, Immunofluorescence, TUNEL Assay, Staining, Analysis, Fluorescence

Journal: Nature Communications

Article Title: Hybrid exosomal nanomotors convert pathological ROS into transport-driving cues to enhance cartilage accumulation in osteoarthritis

doi: 10.1038/s41467-026-76949-8

Figure Lengend Snippet: A qPCR analysis of COL2a1 , MMP13 , and iNOS gene expression levels ( n = 4, biological replicates per group). B – D Schematic illustration and representative immunofluorescence images of COL2A1, MMP13, and iNOS, with corresponding quantitative analysis, scale bar = 50 μm ( n = 3, biological replicates per group). Created in BioRender. Huang, K. ( https://BioRender.com/nqgl3ax ). E , F Western blot analysis of COL2A1, MMP13, and iNOS protein levels, with relative quantitative analysis ( n = 3, biological replicates per group). G , H Safranin O and Alcian blue staining of OA chondrocytes treated with different exosomal formulations, with related quantitative analysis, scale bar = 200 μm ( n = 3, biological replicates per group). Data are presented as the mean ± SD. P values are from one-way analysis of variance (ANOVA) with Tukey’s multiple comparisons test ( A , D , F , H ). Data in ( C , E , G ) are representative of three independent experiments with similar results. Source data are provided as a Source Data file.

Article Snippet: Primary antibodies against ALIX, TSG101, CD81, Calnexin, COL2A1, MMP13, iNOS, Prdx5, Gpx4, Ndufa8, Cox4i1, Traf6, Ikbkg, GAPDH, and VDAC1, used for western blotting, immunofluorescence, and immunohistochemistry, were obtained from Abclonal, China.

Techniques: Analysis, Gene Expression, Immunofluorescence, Western Blot, Staining

Journal: Nature Communications

Article Title: Hybrid exosomal nanomotors convert pathological ROS into transport-driving cues to enhance cartilage accumulation in osteoarthritis

doi: 10.1038/s41467-026-76949-8

Figure Lengend Snippet: A – C Representative histological staining of the affected OA joint treated with different exosomal formulations, including Hematoxylin & Eosin ( A ), Safranin O & Fast Green ( B ), and Toluidine Blue ( C ), scale bar = 200 μm. D – F Quantitative analysis of cartilage thickness ( D ), chondrocyte number ( E ), and OARSI score ( F ) ( n = 4, biological replicates per group). G – I Representative immunohistochemical staining of COL2A1 ( G ), MMP13 ( H ), and iNOS ( I ) in cartilage tissues, scale bar = 200 μm. J – L Quantitative analysis of immunohistochemical expression of COL2A1 ( J ), MMP13 ( K ), and iNOS ( L ) ( n = 4, biological replicates per group). Data are presented as the mean ± SD. P values are from one-way analysis of variance (ANOVA) with Tukey’s multiple comparisons test ( D – E , J – L ), or non-parametric tests (Kruskal-Wallis followed by two-tailed Mann-Whitney U test) ( F ). Data in ( A – C , G – I ) are representative of four independent experiments with similar results. Source data are provided as a Source Data file.

Article Snippet: Primary antibodies against ALIX, TSG101, CD81, Calnexin, COL2A1, MMP13, iNOS, Prdx5, Gpx4, Ndufa8, Cox4i1, Traf6, Ikbkg, GAPDH, and VDAC1, used for western blotting, immunofluorescence, and immunohistochemistry, were obtained from Abclonal, China.

Techniques: Staining, Analysis, Immunohistochemical staining, Expressing, Two Tailed Test, MANN-WHITNEY

Journal: Bioactive Materials

Article Title: A dual-functional hydrogel integrating adhesive and lubricating interfaces for mitochondrial protection–Driven cartilage regeneration

doi: 10.1016/j.bioactmat.2026.02.051

Figure Lengend Snippet: Regulation of extracellular matrix metabolism by AdHy@Pae in LPS-induced chondrocytes. (A) Representative immunofluorescence images showing the expression of COL2A1, SOX9, MMP9, and ADAMTS5 in different treatment groups and corresponding (B) quantitative analysis. Data are shown as mean ± SD (n = 3, ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, ∗∗∗∗P < 0.0001).

Article Snippet: Rat chondrocytes (P1) were seeded in 24-well plates (5 × 10 4 cells per well) and cultured to ∼70–80% confluence, stimulated with LPS (10 μg mL −1 , 12 h) to induce an inflammatory phenotype, and then treated with hydrogel extracts (Hy, AdHy, AdHy@Pae) for 24 h. Cells were washed three times with PBS, fixed in 4% paraformaldehyde for 15 min, permeabilized with 0.1% Triton X-100 (Aladdin, T434386) for 10 min, and blocked with 5% BSA (Solarbio, SW3015) at room temperature for 1 h. Primary antibodies were applied overnight at 4 °C: COL2A1 (Proteintech, 28459-1-AP, 1:200), SOX9 (HUABIO, HA723548, 1:1000), MMP9 (HUABIO, ET1704-69, 1:200), and ADAMTS5 (HUABIO, HA722011, 1:100).

Techniques: Immunofluorescence, Expressing

Journal: Bioactive Materials

Article Title: A dual-functional hydrogel integrating adhesive and lubricating interfaces for mitochondrial protection–Driven cartilage regeneration

doi: 10.1016/j.bioactmat.2026.02.051

Figure Lengend Snippet: Expression analysis of cartilage-related proteins after treatment with AdHy@Pae. (A) Representative Western blot images showing ECM synthesis–related proteins (COL2A1, ACAN, COMP, and SOX9) and antioxidant markers (NRF2 and HO-1) in different groups. (B) Quantitative analysis of matrix-degrading enzymes (MMP13, ADAMTS5, ADAMTS1) and apoptosis-related proteins (BCL-2, Bax, and Caspase-3). Data are presented as mean ± SD (n = 3; ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, ∗∗∗∗P < 0.0001).

Article Snippet: Rat chondrocytes (P1) were seeded in 24-well plates (5 × 10 4 cells per well) and cultured to ∼70–80% confluence, stimulated with LPS (10 μg mL −1 , 12 h) to induce an inflammatory phenotype, and then treated with hydrogel extracts (Hy, AdHy, AdHy@Pae) for 24 h. Cells were washed three times with PBS, fixed in 4% paraformaldehyde for 15 min, permeabilized with 0.1% Triton X-100 (Aladdin, T434386) for 10 min, and blocked with 5% BSA (Solarbio, SW3015) at room temperature for 1 h. Primary antibodies were applied overnight at 4 °C: COL2A1 (Proteintech, 28459-1-AP, 1:200), SOX9 (HUABIO, HA723548, 1:1000), MMP9 (HUABIO, ET1704-69, 1:200), and ADAMTS5 (HUABIO, HA722011, 1:100).

Techniques: Expressing, Western Blot

Journal: Bioactive Materials

Article Title: A dual-functional hydrogel integrating adhesive and lubricating interfaces for mitochondrial protection–Driven cartilage regeneration

doi: 10.1016/j.bioactmat.2026.02.051

Figure Lengend Snippet: In vivo validation of the chondroprotective and mitochondrial regulatory effects of AdHy@Pae after therapy for 4 weeks. (A) Representative immunohistochemical staining of cartilage sections for COL2A1, SOX9, MMP3, and ADAMTS1 in different groups (Sham, PBS, Hy, AdHy, and AdHy@Pae). (B) Quantitative analysis of the immunohistochemical staining intensity showing relative expression levels of anabolic (COL2A1, SOX9) and catabolic (MMP3, ADAMTS1) markers. (C) TEM images of chondrocytes showing mitochondrial ultrastructure in each group, with high-magnification views (bottom panels) indicating cristae integrity and membrane morphology. Data are presented as mean ± SD (n = 3); ∗∗P < 0.01, ∗∗∗P < 0.001, ∗∗P < 0.0001.

Article Snippet: Rat chondrocytes (P1) were seeded in 24-well plates (5 × 10 4 cells per well) and cultured to ∼70–80% confluence, stimulated with LPS (10 μg mL −1 , 12 h) to induce an inflammatory phenotype, and then treated with hydrogel extracts (Hy, AdHy, AdHy@Pae) for 24 h. Cells were washed three times with PBS, fixed in 4% paraformaldehyde for 15 min, permeabilized with 0.1% Triton X-100 (Aladdin, T434386) for 10 min, and blocked with 5% BSA (Solarbio, SW3015) at room temperature for 1 h. Primary antibodies were applied overnight at 4 °C: COL2A1 (Proteintech, 28459-1-AP, 1:200), SOX9 (HUABIO, HA723548, 1:1000), MMP9 (HUABIO, ET1704-69, 1:200), and ADAMTS5 (HUABIO, HA722011, 1:100).

Techniques: In Vivo, Biomarker Discovery, Immunohistochemical staining, Staining, Expressing, Membrane

Journal: Journal of Orthopaedic Translation

Article Title: Dermal fibroblasts attenuate osteoarthritis by restoring synovial fibroblast homeostasis

doi: 10.1016/j.jot.2026.101138

Figure Lengend Snippet: Intra-articular injection of DFbs preserved articular cartilage structure and homeostasis. A) H&E staining and SO/FG staining of articular cartilage. B) Representative micro-CT 3D images and coronal images of knee joints of rats at 8 weeks after ACLT. C) Grading of osteoarthritic cartilage damage (OARSI Criteria). D) Immunofluorescence staining of MMP3, MMP13, iNOS and COL2A1. E) Quantification of positive cells and positive area in the cartilage. n = 6. Data were presented as mean ± SD. Results were analyzed by one-way ANOVA.

Article Snippet: After antigen retrieval via citric acid, three primary antibodies were used, including COL2A1 (Servicebio, China), Vimentin (Servicebio, China) and eGFP (ProteinTech, China).

Techniques: Injection, Staining, Micro-CT, Immunofluorescence

Journal: Journal of Orthopaedic Translation

Article Title: Dermal fibroblasts attenuate osteoarthritis by restoring synovial fibroblast homeostasis

doi: 10.1016/j.jot.2026.101138

Figure Lengend Snippet: DFbs improve the inflammatory phenotype of synovial fibroblasts and chondrocytes via paracrine secretion. A) Schematic of the transwell co-culture system for synovial fibroblasts/chondrocytes and DFbs. B) Volcano plot of DEGs in the FI group and DFI group. C) GO enrichment analysis of DEGs between the FI group and DFI group. D) GSEA highlighting the enrichment of gene sets associated with inflammatory response. E) Expression profiles of inflammation-related genes and cell adhesion-related genes in the three cell groups. F) IL-6 immunofluorescence staining of synovial fibroblasts in the normal culture, IL-1β-stimulated, and IL-1β + DFb co-culture groups. Scale bar: 50 μm (Row 1); 25 μm (Row 2). G) Quantification of IL-6+ cells. n = 3. Data were presented as mean ± SD. Results were analyzed by one-way ANOVA. H) Axial fluorescence intensity of IL-6 in representative synovial fibroblasts. I) Volcano plot of DEGs between the CI group and DCI group. J) Intersection of downregulated genes in IL1β-stimulated chondrocytes and upregulated genes in IL1β-stimulated chondrocytes co-cultured with DFbs (vs. IL1β-stimulated chondrocytes alone) and intersection of upregulated genes in IL1β-stimulated chondrocytes and downregulated genes in IL1β-stimulated chondrocytes co-cultured with DFbs (vs. IL1β-stimulated chondrocytes alone). K) GO enrichment analysis of genes derived from the aforementioned intersection. L) Clustered heatmap of genes related to inflammation and ECM. M) RT-qPCR analysis of Mmp9 , Mmp13 , Acan , and Col2a1 . n = 6. Data were presented as mean ± SD. Results were analyzed by one-way ANOVA. N) Alcian blue staining of chondrocytes in three groups (Control, IL-1β-stimulated group, IL-1β-stimulated + DFb co-culture group). Scale bar: 2 mm.

Article Snippet: After antigen retrieval via citric acid, three primary antibodies were used, including COL2A1 (Servicebio, China), Vimentin (Servicebio, China) and eGFP (ProteinTech, China).

Techniques: Co-Culture Assay, Expressing, Immunofluorescence, Staining, Fluorescence, Cell Culture, Derivative Assay, Quantitative RT-PCR, Control

Journal: Journal of Orthopaedic Translation

Article Title: Dermal fibroblasts attenuate osteoarthritis by restoring synovial fibroblast homeostasis

doi: 10.1016/j.jot.2026.101138

Figure Lengend Snippet: Paracrine APOD from DFbs inhibited inflammatory activation of FLS and catabolic phenotype of chondrocytes. A) Workflow diagram of proteomic sequencing of fibroblast supernatants. B) Intersection of proteins detected in DFb supernatant, human secreted proteins, and human secreted immunoglobulins. C) GO enrichment analysis of secreted proteins from DFbs. D) Intersection of DFb secreted proteins, downregulated DEGs in OA SL Fb, and downregulated DEGs in in vitro cultured OA FLS. E) Cluster heatmap of expression profiles of genes from the aforementioned intersection in DFbs, healthy synovial fibroblasts (HF), and OA FLS. F) Fold change in APOD mRNA expression between healthy SL Fb and OA SL Fb (with healthy SL Fb as the reference). G) Fold change in APOD mRNA expression between healthy synovial fibroblasts (HF), DFb and OA FLS (with healthy synovial fibroblasts as the reference). H, J) RT-qPCR analysis of pro-inflammatory genes ( Nos2 , Il6 , Ptgs2 ) in FLS (H), and matrix metabolic genes ( Mmp9 , Mmp13 , Col2a1 ) in chondrocytes (J), after co-culture with control, empty vector-transfected, APOD-overexpressing (APOD-OE) DFbs, or treatment with recombinant APOD protein. I, K) RT-qPCR analysis of the above gene panels in FLS (I) and chondrocytes (K), after co-culture with control, negative control siRNA-transfected, or APOD-knockdown (APOD-si) DFb. n = 6. Data were presented as mean ± SD. Results were analyzed by one-way ANOVA. ∗∗P < 0.01. L) Representative Western blots of iNOS and IL-6 in FLS from the indicated groups, with β-actin (ACTB) as the loading control. M) Representative Western blots of MMP9 in chondrocytes from the indicated groups, with ACTB as the loading control.

Article Snippet: After antigen retrieval via citric acid, three primary antibodies were used, including COL2A1 (Servicebio, China), Vimentin (Servicebio, China) and eGFP (ProteinTech, China).

Techniques: Activation Assay, Sequencing, In Vitro, Cell Culture, Expressing, Quantitative RT-PCR, Co-Culture Assay, Control, Plasmid Preparation, Transfection, Recombinant, Negative Control, Knockdown, Western Blot