1. Brinks et al., Appendix A - page 10
CSQ
NCX
SERCA2
Normal
AdGFP
AdS100A1
Human heart
HFCMs
ICM
Legend: Abnormal expression of calcium handling proteins in HFCMs. Representative Western Blots for calsequestrin (CSQ), sodium calcium exchanger (NCX) and sarcoplasmic reticulum Ca-ATPase (SERCA2) demonstrate persistent abnormalities in NCX and SERCA2 protein levels in HFCMs despite normalized S100A1 proteins levels after 24 hours. Experiments have been performed in samples from 5 different HFCM isolations with similar results (data not shown).

2. A B C 60 50 40 (ATP nmol/mg protein×min) SR Ca2+ATPase activity 30 20
Brinks et al., Appendix B - page 11
P < 0.05 A 60 50
Legend A: S100A1 gene transfer improves enzymatic SR Ca2+ ATPase (SERCA2a) activity in HFCMs. Ca2+ dependent SERCA2 function determined in microsomal preparations from control and S100A1-expressing HFCMs yielded enhanced Ca2+ ATPase activity. Results shown are from 3 different cell isolations. SERCA2a activity was assessed at pCa 6.2 as thapsigargin-sensitive fraction and given as ATP consumption in nmol per mg microsomal protein and min. 40
(ATP nmol/mg protein×min)
SR Ca2+ATPase activity 30 20
Ad-control
Ad-S100A1 10
HFCMs B C
anti-SERCA 2 AB + blocking peptide
anti-SERCA2 AB
IP: SERCA2
IB: S100A1
EGTA
Ca2+
+ vehicle
+ hrS100A1 (0.1M)
IB pellet: SERCA2
IB supernatant: SERCA2
IB pellet: S100A1
Legend B: Ca2+ dependent interaction of human S100A1 protein with human SERCA2a. Representative Western Blots depict a greater amount of the Ca2+ sensor protein co-precipitating with SERCA2 in the presence of Ca2+ (300 nM free Ca2+) in SR vesicle preparations derived from failing human cardiomyocytes treated with recombinant human S100A1 protein. EGTA (1 mM) prevents the interaction. Experiments have been performed in samples from 4 different HFCM isolations with similar results (data not shown).
Legend C: Control experiment revealing specificity of SERCA2/S100A1 co-immunoprecipitation with the polyclonal goat anti-SERCA2 antibody. The corresponding blocking peptide was pre-incubated with the anti-SERCA2 antibody (5-fold excess) which prevented SERCA2 immunoprecipitation (upper panel). As expected, the remaining supernatant of the anti-SERCA2a/blocking peptide group exhibited a greater SERCA2 signal (middle panel) and absence of co-precipitating S100A1 protein (lower panel).

3. Ca2+ leak (Fluo 3 emission 530 nm)
Brinks et al., Appendix C – page 12 A
control
+ TG
Legend A: S100A1 reduces SR Ca2+ leak in SR vesicle preparations from failing human myocardium. Representative Fluo-3 tracings of SR vesicle preparations from human failing hearts show abrogated Ca2+ leak due to recombinant S100A1 protein treatment (lower tracing) compared with control buffer (upper tracing). Results are representative of 3 different SR vesicle preparations (data not shown). 10
SR Ca2+ leak
Ca2+ leak (Fluo 3 emission 530 nm)
arbitrary units
hrS100A1 (0.1M)
+ TG 10
SR Ca2+ leak
150 sec
IgG1 isotype
control
anti-RyR2 B C
IP: RyR2
EGTA
Ca2+
control
hrS100A1 (0.1M)
IB pellet: RyR2
IB: S100A1
IB supernatant: RyR2
IB pellet: S100A1
Legend B: Ca2+ dependent interaction of human S100A1 protein with human RyR2. Representative Western Blots depict a greater amount of the Ca2+ sensor protein co-precipitating with RyR2 in the presence of Ca2+ (300 nM free Ca2+) in SR vesicle preparations derived from failing human cardiomyocytes treated with recombinant human S100A1 protein. EGTA (1 mM) prevented the interaction. Experiments have been performed in samples from 3 different HFCM isolations with similar results (data not shown).
Legend C: Control experiment revealing specificity of RyR2/S100A1 co-immunoprecipitation with the monoclonal IgG1 anti-RyR2 antibody. The control isotype specific IgG1 antibody did not precipitate RyR2 as shown by the missing RyR2 signal in the pellet (upper panel). As expected, the remaining supernatant exhibited a much stronger RyR2 signal (middle panel). Note that the pellet of IgG1 treated RyR2-free homogenates does not contain S100A1 (lower panel) indicating specificity of S100A1 co-precipitation with RyR2.

4. A B C Brinks et al., Appendix D – page 13
CytC
CSQ
S100A1
S100A1
HS3
CytC
CytC
α-actinin
Adcontrol
AdS100A1
control
S100A1
(0.1 µM)
pre-column lysate
post-column lysate
Legend: Efficacy of human mitochondria isolation and enhanced mitochondrial S100A1 protein content due to AdS100A1 and recombinant S100A1 protein treatment. A, representative Western blots showing efficacy of the mitochondrial isolation protocol. In the pre-column lysate (right, prior to anti-TOM22 magnetic bead purification) consisting of whole cardiac tissue homogenate, markers for mitochondria (cytochrom C; CytC), sarcoplasmic reticulum (calsequestrin; CSQ), sarcomer (α-actinin) and nuclei (histone 3, HS3) are highly abundant. Post-column eluates (left, after anti-TOM22 magnetic bead purification) are free of CSQ, HS3 and α-actinin but enriched in the mitochondrial marker CytC. B, representative Western blots demonstrating enhanced mitochondrial S100A1 protein content after adenoviral overexpression of human S100A1 protein for 24 hours in isolated mitochondria from control and S100A1-expressing HFCMs. C, show representative Western blots of augmented S100A1 content in isolated mitochondria from failing human myocardial tissue that were (pre)incubated with human recombinant S100A1 protein (0.1 µM) for 60 min. CytC served as loading control in B and C. Similar results were obtained with 2 different cellular and tissue preparations (data not shown).

5. Brinks et al., Appendix E – page 14
Ad control
Ad control + Ca2+ 20 40 60 80
100
101
102
103
104 20 40 60 80
100
101
102
103
104 M2 M2
CCCP
51.37%
89.22% 20 40 60 80
100
101
102
103
104 M1 M1
Counts M2 20 40 60 80
100
101
102
103
104
Ad S100A1 20 40 60 80
100
101
102
103
104
Ad S100A1 + Ca2+
97.36% M1 M2 M2
12.43%
25.78% M1 M1
Rh123-FL1
Legend: S100A1 prevents depolarization of mitochondrial membrane potential (ΔΨm). ΔΨm was determined using rhodamine123 (Rh123) in isolated mitochondria derived from control and S100A1-expressing human failing cardiomyocytes. Histogram plots show distribution of depolarized vs. hyperpolarized mitochondria under markers M1 and M2, respectively. Note that S100A1-treated human failing cardiomyocytes revealed a smaller percentage of depolarized mitochondria than control treated cells both under basal conditions and calcium overload (CaCl2: 100 µM). Results are representative for a total of three different isolations. The uncoupler carbonyl cyanide m-chlorophenyl hydrazone (CCCP, 10 µM) was used as a negative control for depolarized ΔΨm.

6. Mitochondrial swelling in % of control + Pi
Brinks et al., Appendix F – page 15 A B
P < 0.01
Ad S100A1
Ad control
Ad S100A1
120
P < 0.01 *
Ad S100A1 + Ca2+
100 *
OD Abs520 = 0.2nm
Ad control 80
P < 0.01
Ad S100A1 + Pi 60 40
Ad control + Ca2+ 20
Time = 3 min
Ad control + Pi
Swelling
Buffer
Mitochondrial swelling in % of control + Pi
Ca2+ Pi
P < 0.01
S100A1
control
120 #
S100A1 protein + Ca2+
100
P < 0.01
OD Abs520 = 0.2nm
S100A1 protein + Pi 80 60
control + Ca2+ 40
Time = 3 min
control + Pi 20
Ca2+ Pi
Legend: S100A1 attenuates mitochondrial membrane permeability transition (mitochondrial swelling). A, linear graph represents representative traces of swelling (decrease in optical density, OD) in isolated mitochondria from control (dashed lines) and S100A1 expressing (solid lines) human failing cardiomyocytes (upper panel) during Pi (KH2PO4: 2mM) and calcium overload (CaCl2: 100 µM) treatment. The lower panel shows representative results for isolated mitochondria from failing human myocardial tissue (pre)treated either with control buffer (dashed lines) or human recombinant S100A1 protein (0.1µM, 60 min, solid lines). B, statistical analysis from 3 different mitochondrial preparations depict S100A1-mediated protection from Pi and calcium induced membrane permeability transition. *P<0.05 control buffer vs. buffer calcium and buffer Pi; # P<0.05 control calcium vs. buffer Pi (n=3).

7. Systolic Heart Failure (HF) S100A1 HF Gene Therapy
Brinks et al., Appendix G – page 16
Proposed model for therapeutic effects of S100A1 in failing human cardiomyocytes
Systolic Heart Failure (HF)
S100A1 HF Gene Therapy
S100A1
Downregulation
Ca2+
Ca2+
S100A1
Recovery
extracellular
[Ca2+]
Contraction
[Ca2+]
Contraction
LLC
NCX
intracellular 1.
Ca transient amplitude 1.
Ca transient amplitude
200 ms
200 ms
- Decreased Ca transient amplitude 2.
SR Ca leak 2.
SR Ca leak
- Enhanced Ca transient amplitude
- Prolonged Ca transient decay
- Accelerated Ca transient decay
- Enhanced diastolic [Ca]
S100A1
S100A1
- Decreased diastolic [Ca]
RyR2
Ca2+
Ca2+
Ca2+
Ca2+
S100A1
Ca2+
S100A1
Ca2+
Ca2+
Ca2+ 3.
diastolic [Ca]
Ca2+ 3.
diastolic [Ca]
Myofilaments
Ca2+
Ca2+ 4.
SR Ca load
Ca2+ 4.
SR Ca load 5.
PCr/ATP 5.
PCr/ATP
Mitochondria
Ca2+
Ca2+
MPT 6. Pi Pi
MPT 6.
PLB
PLB
S100A1
S100A1
S100A1
S100A1
SERCA2
SERCA2 7.
Electron flow and ΔΨm
SR Ca resequestration
SR Ca resequestration 8. 8. 7.
Electron flow and ΔΨm
Legend: Therapeutic actions of S100A1 gene therapy in human failing cardiomyocytes (right) summarized and opposed to pathophysiological alterations in untreated failing cells (1.-8.) with diminished S100A1 expression (left). The figure was modified from Kraus et al. (2009) “S100A1 in cardiovascular health and disease: closing the gap between basic science and clinical therapy.” J Mol Cell Cardiol;47: