Journal: Frontiers in Pharmacology

Article Title: NDP-MSH rescues LPS-induced neuroinflammation, synaptic deficits, and depressive-like behaviors in mice: involvement of MC1R–cAMP/PKA signaling

doi: 10.3389/fphar.2026.1895800

Figure Lengend Snippet: PKA inhibition by H89 abolishes the neuroprotective and antidepressant effects of NDP-MSH. (A) Experimental timeline and grouping strategy. Mice were assigned to Vehicle, LPS, LPS + NDP-MSH(NDP), LPS + NDP-MSH + H89(LNH), or H89 groups. (B) Representative locomotor traces in the OFT. (C) Behavioral assessments. NDP-MSH significantly increased sucrose preference in LPS-treated mice, whereas H89 co-treatment abolished this effect in the SPT. (One-way ANOVA, F (4, 41) = 13.96, p < 0.0001, followed by Tukey’s multiple comparisons test. Vehicle vs. LPS: q (41) = 6.649, p < 0.001; Vehicle vs. LNH: q (41) = 6.804, p < 0.001; LPS vs. NDP: q (41) = 4.128, p < 0.05; NDP vs. LNH: q (41) = 4.237, p < 0.05). NDP-MSH restored total distance traveled reduced by LPS; H89 partly reversed this improvement in the OFT (One-way ANOVA, F (4, 41) = 29.92, p < 0.0001, followed by Tukey’s multiple comparisons test. Vehicle vs. LPS: q (41) = 13.07, p < 0.0001; Vehicle vs. NDP: q (41) = 7.823, p < 0.0001; Vehicle vs. LNH: q (41) = 11.660, p < 0.0001; LPS vs. NDP, q (41) = 5.225, p < 0.01). NDP-MSH partly restored central zone entries reduced by LPS; H89 partly reversed this improvement in the OFT (Kruskal-Wallis non-parametric test, H (4) = 30.23, p < 0.0001, followed by Dunn's multiple comparisons test. Vehicle vs. LPS: Z = 4.745, p < 0.0001; Vehicle vs. NDP: Z = 2.600, p = 0.093; Vehicle vs. LNH: Z = 3.924, p < 0.0001; H89 vs. LPS: Z = 3.615, p < 0.01) (Veh, n = 8; H89, n = 8; LPS, n = 10; NDP, n = 9; LNH, n = 11). (D) ELISA quantification of IL-1β levels in the PFC. NDP-MSH reversed LPS-induced IL-1β elevation, whereas H89 prevented this effect (One-way ANOVA, F (4, 25) = 18.02, p < 0.0001, followed by Tukey’s multiple comparisons test. Vehicle vs. LPS, q (25) = 9.990, p < 0.0001; Vehicle vs. LNH: q (25) = 6.190, p < 0.01; LPS vs. NDP, q (25) = 8.350, p < 0.0001; NDP vs. LNH, q (25) = 4.549, p < 0.05) (n = 6 mice per group). (E) Representative images of mPFC neuronal dendrites by Golgi-Cox staining. Scale bar = 20 μm. Column graphs illustrate the relative spine numbers. NDP-MSH significantly increased spine density reduced by LPS treatment, whereas co-treatment with the PKA inhibitor H89 abolished this restorative effect (One-way ANOVA, F (4, 20) = 36.61, p < 0.0001, followed by Tukey’s multiple comparisons test. Veh vs. LPS, q (20) = 13.07, p < 0.0001; Veh vs. NDP, q (20) = 6.820, p < 0.001; Veh vs. LNH, q (20) = 12.82, p < 0.0001; LPS vs. NDP, q (20) = 6.245, p < 0.01; NDP vs. LNH, q (20) = 5.995, p < 0.01) (n = 5 mice per group, with 4-6 sections per mouse; at least 10 dendritic segments were randomly selected and quantified per section). (F) Quantification of relative Iba-1 fluorescence intensity, NDP-MSH normalized LPS-evoked microglial activation; H89 co-treatment restored microglial density to LPS-like levels (One-way ANOVA, F (4, 10) = 19.57, p < 0.001, followed by Tukey’s multiple comparisons test. Veh vs. LPS, q (10) = 8.650, p < 0.001; Veh vs. LNH, q (10) = 8.412, p < 0.01; LPS vs. NDP, q (10) = 5.940, p < 0.05; NDP vs. LNH, q (10) = 5.702, p < 0.05) (n = 3 mice per group). (G) Representative immunofluorescence images of Iba-1 staining in the mPFC, Scale bar = 100 µm. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001. ****p < 0.0001. Source: BioRender.com .

Article Snippet: Treatment regimens were as follows: vehicle-treated mice received equivalent volumes of saline; the LPS group received lipopolysaccharide (LPS; 1 mg/kg; L2880, Sigma-Aldrich, United States); the LPS + NDP-MSH group received LPS (1 mg/kg) together with NDP-MSH (2 mg/kg; HY-N2466, MedChemExpress, United States); the LPS + NDP-MSH + H89 group received LPS (1 mg/kg), NDP-MSH (2 mg/kg), and the PKA inhibitor H89 (10 mg/kg; HY-15979A, MedChemExpress, United States); and the H89-alone group received H89 (10 mg/kg).

Techniques: Inhibition, Enzyme-linked Immunosorbent Assay, Staining, Fluorescence, Activation Assay, Immunofluorescence

Journal: Frontiers in Pharmacology

Article Title: NDP-MSH rescues LPS-induced neuroinflammation, synaptic deficits, and depressive-like behaviors in mice: involvement of MC1R–cAMP/PKA signaling

doi: 10.3389/fphar.2026.1895800

Figure Lengend Snippet: NDP-MSH Normalizes LPS-induced Metabolic Reprogramming through cAMP/PKA Signaling. (A) Principal component analysis (PCA) score plot of untargeted metabolomic profiles from saline control (CTRL), LPS-treated (LPS), drug-treated (NDP), drug plus inhibitor-treated (LNH), inhibitor alone (H89), and quality control (QC) samples. Biological samples included n = 4 mice per treatment group (CTRL, LPS, NDP, LNH, and H89). QC samples (n = 3) were used for quality control and were excluded from statistical comparisons. (B) Bar plot showing the number of significantly altered metabolites (upregulated and downregulated) across pairwise comparisons (limma, FDR <0.2, |log 2 fold change| ≥ 0.15; QC samples excluded). (C) Scatter plot showing the correlation between LPS-induced metabolic changes (LPS vs. CTRL) and drug-induced changes (NDP vs. LPS). (D) Scatter plot showing the correlation between drug-induced changes (NDP vs. LPS) and inhibitor-on-drug effects (LNH vs. NDP). (E) Heatmap showing a selected subset of metabolites whose LPS-induced changes were reversed by NDP-MSH treatment and whose NDP-MSH-mediated reversal was blocked by H89. Relative metabolite intensities were Z-score normalized across group means. (F) KEGG pathway enrichment analysis of drug-responsive metabolites. Source: BioRender.com .

Article Snippet: Treatment regimens were as follows: vehicle-treated mice received equivalent volumes of saline; the LPS group received lipopolysaccharide (LPS; 1 mg/kg; L2880, Sigma-Aldrich, United States); the LPS + NDP-MSH group received LPS (1 mg/kg) together with NDP-MSH (2 mg/kg; HY-N2466, MedChemExpress, United States); the LPS + NDP-MSH + H89 group received LPS (1 mg/kg), NDP-MSH (2 mg/kg), and the PKA inhibitor H89 (10 mg/kg; HY-15979A, MedChemExpress, United States); and the H89-alone group received H89 (10 mg/kg).

Techniques: Metabolomic, Saline, Control

Journal: Frontiers in Pharmacology

Article Title: Hesperetin and Naringenin promote glucagon-like peptide-1 secretion from L-cell through activation of TGR5 and alleviated type 2 diabetes

doi: 10.3389/fphar.2026.1838267

Figure Lengend Snippet: Hesperetin and Naringenin increased cAMP level and [Ca 2+ ] i after glucose stimulation in murine L cells. (A,B) Intracellular cAMP levels from GLUTag cells in response to 10 μM Hesperetin (A) or 10 μM Naringenin (B) (n = 5). (C,D) GLP-1 secretion from GLUTag cells in response to 10 μM Hesperetin (C) or 10 μM Naringenin (D) with 10 μM H89 or vehicle (n = 5). (E) The intracellular calcium concentration ([Ca 2+ ] i ) of GLUTag cells stimulated with 20 mM glucose plus vehicle or 10 μM Hesperetin was detected by using a Ca 2+ indicator, Fluo‐4 (n = 10). The change of fluorescence after stimulation was normalized to the basal fluorescence (ΔF/F 0 ) was measured by area under the curve (AUC). (F) GLP-1 secretion from GLUTag cells in response to 10 μM Hesperetin with 5 μM Nifedipine or vehicle (n = 5). (G) The intracellular calcium concentration ([Ca 2+ ] i ) of GLUTag cells stimulated with 20 mM glucose plus vehicle or 10 μM Naringenin was detected by using a Ca 2+ indicator, Fluo‐4 (n = 10). The change of fluorescence after stimulation was normalized to the basal fluorescence (ΔF/F 0 ). (H) GLP-1 secretion from GLUTag cells in response to 10 μM Naringenin with 5 μM Nifedipine or vehicle (n = 5). Black arrows indicated the initial time of glucose stimulation. ** p < 0.01, *** p < 0.001 by Mann-Whitney U-test, ns means not significant. Data are expressed as the mean ± SEM.

Article Snippet: H89 (HY-15979), Nifedipine (HY-B0284), GW 4064 (HY-50108), INT777 (HY-15677), TAK-875 (HY-10480), GSK1292263 (HY-12066), TUG-891 (HY-100881) and Exendin-(9-39) amide (HY-P0264) were purchased from MedChemExpress (Shanghai, China).

Techniques: Concentration Assay, Fluorescence, MANN-WHITNEY