Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: Schematic diagram of the experimental setup. Male Wistar rats (7 weeks old; 200–250 g) were divided into four groups (n = 45 each). Temperature-control groups (Cont-Veh, Cont-AG490) were maintained at 24 ± 1 °C, while cold acclimated groups (CA-Veh, CA-AG490) were exposed intermittently to 9 ± 1 °C (8 h daily) and to 24 ± 1 °C (16 h daily) during the first week; followed by 4 weeks of continuous acclimation at 9 ± 1 °C. The JAK2 inhibitor (AG490) or vehicle (Veh) was administered intraperitoneally daily for the last three days of the acclimation period. The final dose was administered 10 min before surgery.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Control

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: Myocardial sensitivity to ischemia and reperfusion following cold exposure and the effect of AG490, and assessment of hemodynamic parameters before and after isoprenaline application. ( A ) The effect of cold acclimation (CA-Veh; 9 ± 1 °C for 5 weeks) and the pharmacological inhibition of JAK2/STAT3 signaling with AG490 (CA-AG490) on infarct size (IS) following in vivo myocardial ischemia–reperfusion (IR) injury, mean arterial blood pressure (MAP) and heart rate (HR). Controls were kept at 24 °C and received either vehicle or AG490 (Cont-Veh; Cont-AG490). Infarct size (IS) is expressed as a percentage of the area at risk (AoR). The AoR is normalized to the left ventricle (LV) as a percentage. ( B ) Echocardiographic parameters: cardiac output (CO), stroke volume (LVSV), fractional shortening (LVFS) and ejection fraction (LVEF) were measured at rest. ( C ) Echocardiographic parameters before and after isoprenaline application, expressed as Δ values (Δ = after isoprenaline injection minus before isoprenaline injection). ( D ) Representative images of echocardiography analysis in all experimental groups (M-Mode, PSSAX). ( E ) Echocardiographic evaluation of wall thickness; left ventricular anterior wall (LVAW), left ventricular posterior wall (LVPW) measured in systole (s) and diastole (d). ( F ) Echocardiographic evaluation of wall thickness before and after isoprenaline application, expressed as Δ values (Δ = after isoprenaline injection minus before isoprenaline injection). The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05; *** p < 0.001.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, In Vivo, Injection, Comparison

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: Mitochondrial parameters and apoptotic markers. The effect of chronic cold exposure (5 weeks, 9 ± 1 °C; CA) and JAK2/STAT3 pathway on ( A ) the maximal rate of Ca 2 ⁺-induced mitochondrial swelling in left ventricular tissue mitochondria following cold acclimation (CA-Veh) and JAK2/STAT3 inhibition (CA-AG490). Mitochondrial swelling was induced by 200 µM Ca 2 ⁺ and expressed as the rate of change in absorbance at 520 nm (ΔA 520 ·s⁻ 1 ). ( B ) Relative protein levels of cleaved Cas-3 in left ventricular post nuclear supernatant (pns). ( C ) Relative expression of mitofusin (MFN-1), dynein related protein (DRP-1) and optic atrophy protein (OPA-1) in mitochondrial fraction (mf). ( D ) Mitochondrial respiratory parameters of Complex I, ATP production and residual oxygen consumption rate (ROX). ( E , F ) Relative protein expression of BAX (pro-apoptotic), Bcl-2 (anti-apoptotic), and the BAX/Bcl-2 ratio in either post nuclear supernatant (pns, panel E ) or mitochondrial fraction (mt, panel F ). Protein levels were normalized to total protein. Representative Western blot images and Ponceau staining of the respective proteins are shown. The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05, ** p < 0.01, *** p < 0.001.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, Expressing, Western Blot, Staining, Comparison

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: The effect of chronic cold exposure (5 weeks, 9 ± 1 °C, CA) and inhibition of JAK2/STAT3 pathway by AG490 on the total (tSTAT3), phosphorylated STAT3 (pSTAT3 Y705 ; pSTAT3 S727 ) intracellular distribution. ( A – C ) Representative micrographs of longitudinal cryo-sections of controls (Cont-Veh, Cont-AG490) and acclimated CA groups (CA-Veh; CA-AG490) shows the following colocalizations and respective graphs: ( A ) Total STAT3 (tSTAT3; green) with mitochondrial compartment (OXPHOS; red) and tSTAT3 with sarcolemma compartment (WGA; shown in graph only), (B) Colocalization of pSTAT3 Y705 (green) with sarcolemma (WGA, red) and (C) pSTAT3 S727 with nuclei (DAPI; blue), and respective graphs. Black and white images represent colocalized pixels quantified by M1 (panels A, B) or M2 (panel B ) Mander’s coefficient in the respective graphs. Scale bars 10 µm (panels A , B ); 20 µm (panel C ). The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05, ** p < 0.01, *** p < 0.001.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, Comparison

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: The effect of chronic cold exposure (5 weeks, 9 ± 1 °C; CA) and inhibition of JAK2/STAT3 pathway by AG490 on the relative expression of the total (tSTAT3), and phosphorylated STAT3 (pSTAT3 Y705 and pSTAT3 S727 ). ( A , B ) Graph shows western blot analyses of samples from post nuclear supernatant (pns; panel A ) and mitochondrial fraction (mf, panel B ) of tSTA3 and pSTAT3 S727 . Representative Western blot images and Ponceau staining of the respective proteins are shown. The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05, ** p < 0.01.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, Expressing, Western Blot, Staining, Comparison

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: Other target proteins of JAK2 downstream pathways—MEK1/2; ERK1/2, p38 MAPK and AKT. The effect of chronic cold exposure (5 weeks, 9 ± 1 °C; CA) and inhibition of JAK2 pathway via AG490. ( A ) Relative protein levels of MEK1/2 (MEK), phosphorylated MEK1/2 (pMEK) and the ratio of pMEK1/2 to MEK1/2 (pMEK/MEK). ( B ) Relative protein levels of ERK1/2 (ERK), phosphorylated ERK1/2 (pERK) and the ratio of pERK1/2 to ERK1/2 (pERK/ERK. ( C ) Relative protein levels of phosphorylated p38 MAPK (p38), phosphorylated p38 MAPK (p-p38) and the ratio of p-p38/p38. ( D ) Relative protein levels of total/Akt/protein kinase B (Akt), its phosphorylated form and the ratio of pAKT/AKT. Protein levels were measured in left ventricular post nuclear supernatant (pns) and normalized to total protein. Representative Western blot images and Ponceau staining of the respective proteins are shown. The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05, *** p < 0.001.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, Western Blot, Staining, Comparison

Journal: Scientific Reports

Article Title: Causal relevance of the JAK/STAT pathway for cardioprotection via cold acclimation

doi: 10.1038/s41598-026-40532-4

Figure Lengend Snippet: Inflammatory markers. The effect of chronic cold exposure (5 weeks, 9 ± 1 °C) and inhibition of JAK2/STAT3 pathway by AG490 on left ventricular (LV) concentrations of ( A ) interleukin 6 (Il-6) and interleukin 10 (IL-10) and their respective ratio (IL-6/IL-10); ( B ) tumor necrosis factor alpha (TNF- α) and interleukin 1-beta (IL-1β) and ( C ) relative protein levels of inflammasome component NLRP3 in the LV. The data were analyzed using a two-way ANOVA with a Tukey’s multiple comparison test. Values are means ± SD; * p < 0.05, ** p < 0.01, *** p < 0.001.

Article Snippet: All groups received either the vehicle (Cont-Veh, CA-Veh) or the JAK2 inhibitor AG490 dissolved in the vehicle (Cont-AG490 or CA-AG490), see Fig. . AG490 (MedChemExpress, USA) was diluted in the vehicle (PEG300, 30%; DMSO, 1%; Tween-80, 5%) and administered intraperitoneally at a dose of 5 mg/kg/day (final volume 0.4 ml).

Techniques: Inhibition, Comparison