Cardiomyocyte-Specific Snrk Prevents Inflammation in the Heart - PubMed (original) (raw)

. 2019 Nov 19;8(22):e012792.

doi: 10.1161/JAHA.119.012792. Epub 2019 Nov 13.

Stephanie M Cossette 1, Qiulun Lu 2, Shreya R Chowdhury 3, Leanne M Harmann 4, Ankan Gupta 1, Andrew D Spearman 5, Dmitry L Sonin 6, Michelle Bordas 1, Suresh N Kumar 7, Amy Y Pan 8, Pippa M Simpson 8, Jennifer L Strande 4, Erin Bishop 3, Ming-Hui Zou 2, Ramani Ramchandran 1 3

Affiliations

Cardiomyocyte-Specific Snrk Prevents Inflammation in the Heart

Karthikeyan Thirugnanam et al. J Am Heart Assoc. 2019.

Abstract

Background The SNRK (sucrose-nonfermenting-related kinase) enzyme is critical for cardiac function. However, the underlying cause for heart failure observed in Snrk cardiac conditional knockout mouse is unknown. Methods and Results Previously, 6-month adult mice knocked out for Snrk in cardiomyocytes (CMs) displayed left ventricular dysfunction. Here, 4-month adult mice, on angiotensin II (Ang II) infusion, show rapid decline in cardiac systolic function, which leads to heart failure and death in 2 weeks. These mice showed increased expression of nuclear factor κ light chain enhancer of activated B cells (NF-κB), inflammatory signaling proteins, proinflammatory proteins in the heart, and fibrosis. Interestingly, under Ang II infusion, mice knocked out for Snrk in endothelial cells did not show significant systolic or diastolic dysfunction. Although an NF-κB inflammation signaling pathway was increased in Snrk knockout endothelial cells, this did not lead to fibrosis or mortality. In hearts of adult mice knocked out for Snrk in CMs, we also observed NF-κB pathway activation in CMs, and an increased presence of Mac2+ macrophages was observed in basal and Ang II-infused states. In vitro analysis of Snrk knockdown HL-1 CMs revealed similar upregulation of the NF-κB signaling proteins and proinflammatory proteins that was exacerbated on Ang II treatment. The Ang II-induced NF-κB pathway-mediated proinflammatory effects were mediated in part through protein kinase B or AKT, wherein AKT inhibition restored the proinflammatory signaling protein levels to baseline in Snrk knockdown HL-1 CMs. Conclusions During heart failure, SNRK acts as a cardiomyocyte-specific repressor of cardiac inflammation and fibrosis.

Keywords: NF‐kB; cardiac hypertrophy; cardiomyocyte; endothelial cell; fibrosis; heart failure; inflammation.

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Figures

Figure 1

Figure 1

Angiotensin II (Ang

II

) induces cardiac failure in 2 weeks in Snrk cmc

KO

mice. A through C, Echocardiogram results for baseline 4‐month‐old Snrk wild‐type (

WT

) mice and cardiac‐specific knockout (Snrk cmc

KO

) mice with Ang

II

infused for 14 days into Snrk

WT

mice and 14 days into cardiac‐specific knockout (Snrk cmc

KO

) mice as described before.15 All data were normalized to body weight (

BW

) and presented as such. The parameters analyzed are interventricular septum thickness at end‐diastole (

IVS

d/

BW

), left ventricular internal dimension at end‐diastole (

LVID

d/

BW

), left ventricular posterior wall thickness at end‐diastole (

LVPW

d/

BW

), left ventricular internal dimension at end‐systole (

LVID

s/

BW

), end‐diastole volume (

EDV

/

BW

), end‐systolic volume (

ESV

/

BW

), isovolumic relaxation time (

IVRT

), peak velocity of early diastolic transmitral flow (E), early diastolic mitral annular velocity (e′), pulmonary acceleration rate (

PAT

), ejection time (

ET

), ejection fraction (

EF

), fractional shortening (

FS

). Results are presented as mean±

SEM

(*P<0.05, # P<0.01). The statistical comparison for P value was done by comparing Snrk

WT

vs Snrk cmc

KO

, Snrk

WT

vs Snrk

WT

‐Ang

II

, Snrk cmc

KO

vs Snrk cmc

KO

‐Ang

II

, and Snrk

WT

‐Ang

II

vs Snrk cmc

KO

‐Ang

II

(n=6 for the WT group and n=3 for Snrk cmc

KO

and the Ang

II

–induced experimental group).

Figure 2

Figure 2

Angiotensin II (Ang

II

)–infused hearts from Snrk conditional knockout mice and Snrk knockdown cardiomyocytes (

CM

s) show higher levels of proinflammatory response. A and B, Hearts from Snrk cmc

KO

and (C and D) Snrk ec

KO

mice were assessed for pro‐ and anti‐inflammatory signaling by immunoblotting. Both knockout mouse groups were analyzed under vehicle‐treated and Ang

II

–induced conditions similar to wild‐type (WT) control mice.

NF

‐κB p‐p65,

IL

‐6, and

TNF

‐α were assessed for proinflammatory signaling, and

IL

‐10 was assessed for anti‐inflammatory signaling. Results are presented as mean±

SEM

(*P<0.05 and # P<0.01). The statistical comparison for P value was done by comparing Snrk

WT

vs Snrk cmc

KO

, Snrk

WT

vs Snrk

WT

‐Ang

II

, Snrk cmc

KO

vs Snrk cmc

KO

‐Ang

II

and Snrk

WT

‐Ang

II

vs Snrk cmc

KO

‐Ang

II

(n=3 animals in each experimental group). E and F,

HL

‐1 cardiomyocyte cells were treated with Snrk small interfering (si)

RNA

with and without Ang

II

and assessed for pro‐ and anti‐inflammatory signaling. Results are presented as mean±

SEM

(*P<0.05 and # P<0.01). The statistical comparison for P value was done by comparing control si

RNA

vs Snrk si

RNA

, control si

RNA

vs control si

RNA

‐Ang

II

, Snrk si

RNA

vs Snrk si

RNA

‐Ang

II

, and control si

RNA

‐Ang

II

vs Snrk si

RNA

‐Ang

II

(n=3 in each experimental group). cmcKO indicates cardiomyocyte knockout; ecKO, endothelial cell knockout; SEM, standard error of the mean.

Figure 3

Figure 3

Angiotensin II (Ang

II

)–infused hearts from Snrk cmc

KO

and Snrk knockdown cardiomyocytes (

CM

s) show changes in

pAKT

and

pERK

signaling pathways. A and B, Immunoblotting analysis of

HL

‐1 cardiomyocytes were treated with Snrk small interfering (si)

RNA

with and without Ang

II

(1 μmol/L) for 24 hours. Results are presented as mean±

SEM

(*P<0.05). Statistical comparison for P value was done by comparing control si

RNA

vs Snrk si

RNA

, control si

RNA

vs control si

RNA

‐Ang

II

, Snrk si

RNA

vs Snrk si

RNA

‐Ang

II

, and control si

RNA

‐Ang

II

vs Snrk si

RNA

‐Ang

II

(n=3 in each experimental group). C and D, Snrk cmc

KO

mouse hearts were assessed for phosphorylated forms of

AKT

and

ERK

signaling by immunoblotting, KO mouse hearts were analyzed under vehicle‐treated and Ang

II

–induced conditions, wild‐type (WT) mice were used as controls for both conditions. Results are presented as mean±

SEM

(*P<0.05 and # P<0.01). The statistical comparison for P value was done by comparing Snrk

WT

vs Snrk cmc

KO

, Snrk

WT

vs Snrk

WT

‐Ang

II

, Snrk cmc

KO

vs Snrk cmc

KO

‐Ang

II

, and Snrk

WT

‐Ang

II

vs Snrk cmc

KO

‐Ang

II

(n=3 animals in each experimental group). E and F, Briefly,

HL

‐1 cardiomyocyte cells were subjected to Snrk si

RNA

transfection and treated with and without

AKT

inhibitor

LY

294002 (10 μmol/L) for 24 hours and assessed for phosphorylated

AKT

and the proinflammatory

NF

‐κB p‐p65,

IL

‐6, and

TNF

‐α and anti‐inflammatory

IL

‐10 signaling.

DMSO

‐treated cells served as control. Results are presented as mean±

SEM

(*P<0.05 and # P<0.01 compared with respective treatment groups; n=3 in each experimental group). cmcKO indicates cardiomyocyte knockout; SEM, standard error of the mean.

Figure 4

Figure 4

AKT

inhibition under angiotensin II (Ang

II

)–stimulated conditions in cardiomyocytes (

CM

s) attenuate inflammation. A,

HL

‐1

CM

s were transfected with control and Snrk small interfering (si)

RNA

, studied with and without Ang

II

(1 μmol/L) and/or

AKT

inhibitor

LY

294002 (10 μmol/L), and assessed for phosphorylated‐

AKT

(p‐

AKT

) and proinflammatory markers

NF

‐κB p‐p65,

IL

‐6, and

TNF

‐α. Untreated cells served as control. Results are presented as mean±

SEM

(*P<0.05 and # P<0.01 vs respective control si

RNA

‐treated cells; n=3 in each experimental group). B, Quantification of blots from sample in A. C through E, Snrk cmc

KO

hearts were analyzed for fibrosis using Sirius red staining, which showed an exacerbated fibrotic environment determined by increased accumulation of collagen in the hearts. The mice were treated with vehicle control (C) and Ang II (D). Significant increases in the accumulation of collagen in the Snrk cmc

KO

mice were observed compared with wild type (WT); on stimulation with Ang

II

the collagen deposition increases further. Results are presented as mean±

SEM

(# P<0.01). The statistical comparison for P value was done by comparing Snrk

WT

vs Snrk cmc

KO

, Snrk

WT

vs Snrk

WT

–Ang

II

, Snrk cmc

KO

vs Snrk cmc

KO

–Ang

II

, and Snrk

WT

–Ang

II

vs Snrk cmc

KO

–Ang

II

(n=3 animals in each experimental group). cmcKO indicates cardiomyocyte knockout; SEM, standard error of the mean; veh, vehicle.

Figure 5

Figure 5

SNRK

enhances angiotensin II (Ang

II

)–induced inflammation in Snrk cmc

KO

hearts. A, Wild‐type (WT) and Snrk cardiac knockout mice (cmc

KO

) were treated with vehicle control and Ang II (B). Increased infiltration of macrophages in the Snrk cmc

KO

mice was observed compared with WT on stimulation with Ang

II

, and macrophage numbers further increased. Scale bars are 250 μm for Snrk

WT

, Snrk cmc

KO

, and Snrk

WT

‐Ang

II

and 100 μm for Snrk cmc

KO

‐Ang

II

. C, Results are presented as mean±

SEM

(*P<0.05 and # P<0.01). The statistical comparison for P value was done by comparing Snrk

WT

vs Snrk cmc

KO

, Snrk

WT

vs Snrk

WT

–Ang

II

, Snrk cmc

KO

vs Snrk cmc

KO

–Ang

II

, and Snrk

WT

–Ang

II

vs Snrk cmc

KO

–Ang

II

(n=3 animals in each experimental group). SEM indicates standard error of the mean; veh, vehicle.

Figure 6

Figure 6

NF

‐κB transcription and expression in

HL

‐1 cardiomyocytes. A and B, Flow cytometry analysis for detection of

HL

‐1 cells positive for the expression of

NF

‐κB p‐p65. Results are presented as mean±

SEM

(# P<0.01). The statistical comparison for P value was done by comparing control small interfering (si)

RNA

vs Snrk si

RNA

, control si

RNA

vs Control si

RNA

–angiotensin II (Ang

II

), Snrk si

RNA

vs Snrk si

RNA

–Ang

II

, and control si

RNA

–Ang

II

vs Snrk si

RNA

–Ang

II

(n=3 per each experimental group). C and D, Reporter vector gene assay for the analysis of transcriptional activation of

NF

‐κB.

NF

‐κB vector was tagged with

GFP

protein,

RFP

acted as positive control for the assessment of infection efficiency. Scale bars are at 200 μm. Results are presented as mean±

SEM

(*P<0.05). The statistical comparison for P value was done by comparing control si

RNA

vs Snrk si

RNA

, control si

RNA

vs control si

RNA

–Ang

II

, Snrk si

RNA

vs Snrk si

RNA

–Ang

II

, and control si

RNA

–Ang

II

vs Snrk si

RNA

–Ang

II

(n=12 in each experimental group). E and F,

HL

‐1 cells were treated with

AKT

inhibitor/Ang

II

, where Ang

II

–treated

HL

‐1 cells show more

NF

‐κB p‐p65. The resulting colocalizations were quantified using ImageJ software and represented as graphs. Scale bars are at 1 μm. Results are presented as mean±

SEM

(# P<0.01 vs untreated control cells; n=3 in each experimental group). GFP indicates green fluorescent protein; MFI, Mean Fluorescence Intensity; RFP, red fluorescent protein; SEM, standard error of the mean.

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