human recombinant dpp4  (R&D Systems)

Journal: Investigative Ophthalmology & Visual Science

Article Title: Dipeptidyl Peptidase 4, a Novel Adipokine, Impairs Retinal Microcirculation in Patients With Type 2 Diabetes Mellitus

doi: 10.1167/iovs.66.14.4

Figure Lengend Snippet: Effect of DPP4 intraluminal incubation on the BK-induced vasodilation of the retinal arterioles ( A ). The dose-dependent effect of DPP4 in response to BK is examined before (control, n = 16), and after intraluminal incubation with 100 ng/mL ( n = 4), 400 ng/mL ( n = 4), or 1 µg/mL ( n = 8) DPP4 for 3 hours ( B ). The time-course effect of DPP4 in response to BK is examined before (control), and after intraluminal incubation with 1 µg/mL DPP4 for 1, 2, and 3 hours ( n = 8). * P < 0.05 versus control.

Article Snippet: Human recombinant DPP4 was purchased from R&D Systems, and DPP4 inhibitor teneligliptin was obtained from Mitsubishi Tanabe Pharma Co., Ltd. (Osaka, Japan).

Techniques: Incubation, Control

Journal: Investigative Ophthalmology & Visual Science

Article Title: Dipeptidyl Peptidase 4, a Novel Adipokine, Impairs Retinal Microcirculation in Patients With Type 2 Diabetes Mellitus

doi: 10.1167/iovs.66.14.4

Figure Lengend Snippet: Effect of coadministration of DPP4 with superoxide scavenger, NADPH oxidase inhibitor, xanthine oxidase inhibitor, or DPP4 inhibitor ( A ). The dilation of the retinal arterioles to BK is examined before (control, n = 14) and after intraluminal incubation with 1 µg/mL DPP4 plus the superoxide anion scavenger TEMPOL (1 mM; n = 5), the NADPH oxidase inhibitor apocynin (100 µM; n = 4), or the xanthine oxidase inhibitor allopurinol (10 µM; n = 5) ( B ). Dilation of the retinal arterioles in response to BK is examined before (control, n = 5) and after intraluminal incubation with 1 µM plus the DPP4 inhibitor teneligliptin (0.5 µM; n = 5). * P < 0.05 versus control. † P < 0.05 versus DPP4 alone.

Article Snippet: Human recombinant DPP4 was purchased from R&D Systems, and DPP4 inhibitor teneligliptin was obtained from Mitsubishi Tanabe Pharma Co., Ltd. (Osaka, Japan).

Techniques: Control, Incubation

Journal: Small Science

Article Title: Sustained‐Release Sitagliptin Microneedles for Scar Prevention via Fibroblast‐to‐Adipocyte Conversion

doi: 10.1002/smsc.202500140

Figure Lengend Snippet: DPP4 − KMSCs exhibit higher adipogenic potential in vitro. A–D) Keloid tissues were collected, minced, and seeded to isolate and culture keloid‐derived fibroblasts (A). The isolated fibroblasts were then differentiated toward adipogenic (B), osteogenic (C), and chondrogenic fates (D). E) Surface marker expressions were analyzed using flow cytometry. F) Keloid‐derived DPP4 + and DPP4 − fibroblasts were sorted via fluorescence‐activated cell sorting. G) RT‐qPCR was performed to evaluate the mRNA level of OCT4 , MYC , SOX2 , and NANOG . n = 3; *, p < 0.05. H–J) Sorted DPP4 +/− fibroblasts underwent adipogenic induction, followed by Oil Red O staining and quantification analysis (H–I). Ten random fields per sample were analyzed. The mRNA levels of adipogenesis‐related genes were detected using RT‐qPCR (J); n = 3. Scale bars, 100 μm in (A, B, C, D, and H). Data are presented as mean ± SEM; statistical significance was determined by Student's t ‐test.

Article Snippet: To identify the direct truncation of IGF1 by DPP4, recombinant human IGF1 (rhIGF1, 291‐G1, R&D Systems, Minneapolis, MN) was incubated with a recombinant human DPP4 Fc chimera (11141‐SE, R&D Systems). rhDPP4/Fc was diluted to a concentration of 0.2 ng μL −1 in the assay buffer, and 1 μL of the diluted rhDPP4/Fc was added to 15 μL of diluted rhIGF1 (1 μg μL −1 ).

Techniques: In Vitro, Derivative Assay, Isolation, Marker, Flow Cytometry, Fluorescence, FACS, Quantitative RT-PCR, Staining

Journal: Small Science

Article Title: Sustained‐Release Sitagliptin Microneedles for Scar Prevention via Fibroblast‐to‐Adipocyte Conversion

doi: 10.1002/smsc.202500140

Figure Lengend Snippet: DPP4 − KMSCs demonstrate enhanced adipogenic capacity, whereas DPP4 + KMSCs demonstrate increased fibrotic capacity in vivo. FACS‐sorted DPP4 + and DPP4 − cells were subcutaneously transplanted into Balb/c nude mice. A) The volume of subcutaneously transplanted KMSCs in mice was measured, n = 9. B–D) Adipocyte formation was evaluated by (B) H&E staining (black arrow) and (C) immunofluorescence staining of Perilipin and HLA‐ABC. The black arrow indicates the newly formed adipocytes. (D) The numbers of adipocytes and immature adipocytes were analyzed; n = 6. E,F) Masson's trichrome staining and G,H) immunofluorescence staining of COL1A1 were performed to evaluate collagen deposition. The expression of I,J) PPARγ and K,L) CEBPα was examined by immunofluorescence staining. n = 6. **, p < 0.01. Scale bars, 200 μm in (B), 100 μm in (C), 20 μm in (E, G, I, and K). Data were presented as mean ± SEM. Statistical significance was determined by Student's t ‐test.

Article Snippet: To identify the direct truncation of IGF1 by DPP4, recombinant human IGF1 (rhIGF1, 291‐G1, R&D Systems, Minneapolis, MN) was incubated with a recombinant human DPP4 Fc chimera (11141‐SE, R&D Systems). rhDPP4/Fc was diluted to a concentration of 0.2 ng μL −1 in the assay buffer, and 1 μL of the diluted rhDPP4/Fc was added to 15 μL of diluted rhIGF1 (1 μg μL −1 ).

Techniques: In Vivo, Staining, Immunofluorescence, Expressing

Journal: Small Science

Article Title: Sustained‐Release Sitagliptin Microneedles for Scar Prevention via Fibroblast‐to‐Adipocyte Conversion

doi: 10.1002/smsc.202500140

Figure Lengend Snippet: Sitagliptin‐mediated adipogenic promotion is dependent on protection of IGF1 from DPP4 cleavage. A) Schematic of DPP4‐driven peptide/protein truncation. B–D) DPP4 directly truncates IGF1 but not BMP4. Recombinant human IGF‐I or BMP4 was incubated with recombinant human DPP4 Fc chimera for the cleaving assay, and the product was analyzed using HPLC‐MS/MS. (B) The peptide starting with “ETLC” (red arrow) represented the truncated product of IGF1 by DPP4 and (C) peptide starting with “KHHS” represented the truncated product of BMP4 by DPP4. (D) Percentages of truncated product from the cleaving assay were calculated. E–I) KMSCs underwent adipogenic induction and treated with sitagliptin (20 μM) or combined with the IGF‐1 signaling pathway inhibitor picropodophyllin (PPP, 50 nM), the mRNA and protein levels of adipogenesis‐related molecules were detected by RT‐qPCR E) and F–I) western blotting and quantification analysis. n = 3; *, p < 0.05, **, p < 0.01. Cont. medium, control medium, diff. medium, differentiation medium. Sitag, sitagliptin. M, marker. Data was presented as mean ± SEM. Statistical significance was determined by one‐way analysis of variance (ANOVA) followed by Tukey's HSD post hoc test.

Article Snippet: To identify the direct truncation of IGF1 by DPP4, recombinant human IGF1 (rhIGF1, 291‐G1, R&D Systems, Minneapolis, MN) was incubated with a recombinant human DPP4 Fc chimera (11141‐SE, R&D Systems). rhDPP4/Fc was diluted to a concentration of 0.2 ng μL −1 in the assay buffer, and 1 μL of the diluted rhDPP4/Fc was added to 15 μL of diluted rhIGF1 (1 μg μL −1 ).

Techniques: Recombinant, Incubation, Tandem Mass Spectroscopy, Quantitative RT-PCR, Western Blot, Control, Marker

Journal: Small Science

Article Title: Sustained‐Release Sitagliptin Microneedles for Scar Prevention via Fibroblast‐to‐Adipocyte Conversion

doi: 10.1002/smsc.202500140

Figure Lengend Snippet: Illustration of our work. In scar tissues, IGF1 is cleaved by DPP4 enzyme in DPP4 + KMSC. Cleaved IGF1 may induce KMSC differentiation toward myofibroblasts, whereas IGF1 protected by sitagliptin acts as an adipogenic agent.

Article Snippet: To identify the direct truncation of IGF1 by DPP4, recombinant human IGF1 (rhIGF1, 291‐G1, R&D Systems, Minneapolis, MN) was incubated with a recombinant human DPP4 Fc chimera (11141‐SE, R&D Systems). rhDPP4/Fc was diluted to a concentration of 0.2 ng μL −1 in the assay buffer, and 1 μL of the diluted rhDPP4/Fc was added to 15 μL of diluted rhIGF1 (1 μg μL −1 ).

Techniques:

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 1. Effects of pharmacological modulation of endogenous DPP4 in HEK APPwt cells on full-length Aβ expression. Full-length Aβ immuno- reactivity in HEK APPwt cells treated without (control) or with phosphoramidon (PA), PL302, PL250, and P32/98 (aminopeptidase A, aminopeptidase M, and DPP4 inhibitors, respectively) was quantitated by densitometry. Values are expressed as the percentage of control untreated cells (taken as 100) and are the means ± SEM of 6 to 17 determinations obtained from seven independent experiments. *p < 0.05 and ****p < 0.0001 (Mann–Whitney test). Aβ, amyloid β; APPwt, WT APP; DPP4, dipeptidyl aminopeptidase 4; flAβ, full-length Aβ; HEK, human embryonic kidney.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: Expressing, Control, MANN-WHITNEY

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 2. DPP4 releases the N-terminal dipeptide of Aβ40. HPLC chromatograms of Aβ1-40 (A) and Aβ3-40 (B) peptides and their spectral deconvolution revealing m/z values (4327.1515 and 4141.0908, respectively) recovered after a 6-h incubation of human recombinant DPP4 with synthetic Aβ40. C, Aβ3-40/ Aβ1-40 ratio is represented over time in presence or absence of rDPP4, with or without p32/98 inhibitor. D, quantification of Aβ3-40/Aβ1-40 ratio observed after 8 h. Values are the means ± SEM of 5 to 6 determinations obtained from three independent experiments. (**p < 0.01; one-way ANOVA with Dunn’s multiple comparisons post-test). Aβ, amyloid β; AA, average area; DPP4, dipeptidyl aminopeptidase 4; ns, not statistically significant; RT, retention time; SN, signal noise.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: Incubation, Recombinant

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 3. DPP4 pharmacological blockade influences synaptic morphology. Organotypic slices (see procedure in panel A) were infected with green (B, left panel), APPwt (B, middle panel), or APPswe (B, right panel) lentivirus coexpressing green protein (B) treated or not for 24 h with sitagliptin (100 μM). C, graph represents the percentage of spines corresponding to mushroom (red bars), stubby (yellow bars), and immature (filopodia, green bars) categories and are the means ± SEM of 10 to 22 determinations obtained from two independent experiments. **p < 0.01, ***p < 0.005, ****p < 0.0001, (the Kruskal–Wallis test with Dunn’s multiple comparisons post-test). Scale bars in B upper panels correspond to 300 μm. APPswe, APP bearing the Swedish mutation; APPwt, WT APP; DPP4, dipeptidyl aminopeptidase 4; ns, not statistically significant.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: Infection, Mutagenesis

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 4. Aβ42-positive plaques and Aβ load are decreased in 3xTg-AD mouse brain after shRNA-mediated reduction of endogenous DPP4. A, immu- nohistochemicalanalysisusingtheanti-Aβ42antibody in12-month-old3xTg-ADmiceinfectedwithlentivirusesbearingeithershScrorshDPP4. ScalebarsinpanelA correspond to 500 μm (4×) or 100 μm (10×). B, graph represents the number of Aβ42-positive plaques per square millimeters. C and D, graphs represent the mean perimeter (C) and area (D) of Aβ42-positive plaques. B–D, data are the means± SEM of 5 (shScr) or 7 (shDPP4)-injected mice(Mann–Whitney test). *p < 0.05. Aβ40 (E) and Aβ42(F) measured by ELISA in insolublefractions preparedfrom 12-month-old3xTgWT and 3xTg-ADtransgenic miceinfected with shScror shDPP4 lentiviruses as in panel A. Values are the means ± SEM of 6 (WTshScr and WtshDPP4) or 14 to 15 (shScr- and shDPP4-injected 3xTg-AD) determinations obtained from two independent experiments and are expressed in pg per mg of tissue. ****p < 0.0001 (Mann–Whitney test). 3xTg-AD, triple transgenic AD; Aβ, amyloid β; AD, Alz- heimer’s disease; DPP4, dipeptidyl aminopeptidase 4; shDPP4, shRNA probes targeting DPP4; shScr, shRNA corresponding to a control scramble sequence.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: shRNA, Injection, MANN-WHITNEY, Enzyme-linked Immunosorbent Assay, Transgenic Assay, Control, Sequencing

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 6. shDPP4 treatment partly restores learning and memory deficits in 3xTg-AD mouse model. A, graphical representation of the latency to reach the platform in Morris water maze for 3xTgWT (light green and red curves) and 3xTg-AD (dark green and red curves) mice infected with lentiviruses expressing shScr (light and dark red curves) or shDPP4 (light and dark green curves). B, swimming trajectories of indicated treated mice. Panel C shows the number of entries in each quadrant of the Morris water maze. (WT shScr: n = 11; WT shDPP4: n = 12; 3xTg-AD shScr: n = 9; 3xTg-AD shDPP4: n = 11). *p < 0.05; **p < 0.01; ***p < 0.005 (InVivoStat test). 3xTg-AD, triple transgenic AD; AD, Alzheimer’s disease; DPP4, dipeptidyl aminopeptidase 4; NE, north east; NW, north west; SE, south east; shDPP4, shRNA probes targeting DPP4; SW, south west.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: Infection, Expressing, Transgenic Assay, shRNA

Journal: Journal of Biological Chemistry

Article Title: Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

doi: 10.1016/j.jbc.2021.100963

Figure Lengend Snippet: Figure 7. DPP4 enzymatic activity is transiently increased in sporadic AD-affected brains. DPP4 enzymatic activity was measured by fluorimetry as described in Experimental procedures in human brain samples from different Braak stages patients (see Table S1) (controls: n = 10; AD I-III: n = 9; AD IV-V, n = 10; AD VI: n = 14; *p < 0.05, **p < 0.01, ***p < 0.0005, and ****p < 0.0001). (Two-way ANOVA test with Dunnett’s multiple comparisons test). AD, Alzheimer’s disease; DPP4, dipeptidyl aminopeptidase 4.

Article Snippet: MS Synthetic Aβ40 from Bachem (15 ng/μl) was incubated for various time periods with human recombinant DPP4 (2 ng/μl) (R&D System) or for 6 h with or without the DPP4 inhibitor p32/98 (100 μM).

Techniques: Activity Assay