Cellular Prion Protein Is Essential for Myocardial Regeneration but Not the Recovery of Left Ventricular Function from Apical Ballooning

Distinct phenotypes induced by acute hypoxia and TGF-β1 in human adult cardiac fibroblasts

Myocardial infarction (MI) causes hypoxic injury to downstream myocardial tissue, which initiates a wound healing response that replaces injured myocardial tissue with a scar. Wound healing is a complex process that consists of multiple phases, in which many different stimuli induce cardiac fibroblasts to differentiate into myofibroblasts and deposit new matrix. While this process is necessary to replace necrotic tissue, excessive and unresolved fibrosis is common post-MI and correlated with heart failure. Therefore, defining how cardiac fibroblast phenotypes are distinctly regulated by stimuli that are prevalent in the post-MI microenvironment, such as hypoxia and transforming growth factor-beta (TGF-β), is essential for understanding and ultimately mitigating pathological fibrosis. In this study, we acutely treated primary human adult cardiac fibroblasts with TGF-β1 or hypoxia and then characterized their phenotype through immunofluorescence, quantitative RT-PCR, and proteomic analysis. We found that fibroblasts responded to low oxygen with increased localization of hypoxia inducible factor 1 (HIF-1) to the nuclei after 4h, which was followed by increased gene expression of vascular endothelial growth factor A (VEGFA), a known target of HIF-1, by 24h. Both TGF-β1 and hypoxia inhibited proliferation after 24h. TGF-β1 treatment also upregulated various fibrotic pathways. In contrast, hypoxia caused a reduction in several protein synthesis pathways, including collagen biosynthesis. Collectively, these data suggest that TGF-β1, but not acute hypoxia, robustly induces the differentiation of human cardiac fibroblasts into myofibroblasts. Discerning the overlapping and distinctive outcomes of TGF-β1 and hypoxia treatment is important for elucidating their roles in fibrotic remodeling post-MI and provides insight into potential therapeutic targets.

Melatonin-Assisted Cisplatin Suppresses Urinary Bladder Cancer Cell Proliferation and Growth through Inhibiting PrPC-Regulated Cell Stress and Cell Proliferation Signaling

This study investigated whether melatonin (Mel) would promote cisplatin to suppress the proliferation and growth of bladder cancer (BC) cells by inhibiting cellular prion protein (PrP^C)-mediated cell stress and cell proliferation signaling. An immunohistochemical staining of tissue arrays from BC patients demonstrated that the PrP^C expression was significantly upregulated from stage I to III BC (p < 0.0001). The BC cellline of T24 was categorized into G1 (T24), G2 (T24 + Mel/100 μM), G3 (T24+cisplatin/6 μM), G4 (PrP^C overexpression in T24 (i.e., PrP^C-OE-T24)), G5 (PrP^C-OE-T24+Mel), and G6 (PrP^C-OE-T24+cisplatin). When compared with a human uroepithelial cell line (SV-HUC-1), the cellular viability/wound healing ability/migration rate were significantly increased in T24 cells (G1) and further significantly increased in PrP^C-OE-T24 cells (G4); and they were suppressed in Mel (G2/G5) or cisplatin (G3/G6) treatment (all p < 0.0001). Additionally, the protein expressions of cell proliferation (PI3K/p-Akt/p-m-TOR/MMP-9/PrP^C), cell cycle/mitochondrial functional integrity (cyclin-D1/clyclin-E1/ckd2/ckd4/mitochondrial-cytochrome-C/PINK1), and cell stress (RAS/c-RAF/p-MEK1/2, p-ERK1/2) markers showed a similar pattern of cell viability among the groups (all p < 0.001). After the BC cell line of UMUC3 was implanted into nude mouse backs, by day 28 mthe BC weight/volume and the cellular levels of PrP^C/MMP-2/MMP-9 were significantly, gradually reduced from groups one to four (all p < 0.0001). The protein expressions of cell proliferation (PI3K/p-Akt/p-m-TOR/MMP-9/PrP^C), cell cycle/mitophagy (cyclin-D1/clyclin-E1/ckd2/ckd4/PINK1), and cell stress (RAS/c-RAF/p-MEK1,2/p-ERK1,2) signaling were significantly, progressively reduced from groups one to four, whereas the protein expressions of apoptotic (Mit-Bax/cleaved-caspase-3/cleaved-PARP) and oxidative stress/mitochondrial damaged (NOX-1/NOX-2/cytosolic-cytochrome-C/p-DRP1) markers expressed an opposite pattern of cell proliferation signaling among the groups (all p < 0.0001). Mel-cisplatin suppressed BC cell growth/proliferation via inhibiting the PrP^C in upregulating the cell proliferation/cell stress/cell cycle signaling.

Prion Protein Overexpression in Adipose-Derived Mesenchymal Stem Cells (ADMSCs) Effectively Protected Rodent Kidney Against Ischemia-Reperfusion Injury Via Enhancing ATP/Mitochondrial Biogenesis-Role of ADMSC Rejuvenation and Proliferation

BACKGROUND

We tested the hypothesis that overexpression of cellular-prion-protein in adipose-derived mesenchymal stem cells (PrPCOE-ADMSCs) effectively protected the kidney against ischemia-reperfusion (IR) injury in rat.

METHODS

Part I of cell culture was categorized into A1(ADMSCs)/A2(ADMSCs+p-Cresol)/A3(PrPCOE in ADMSCs)/A4 (PrPCOE in ADMSCs+p-Cresol). Part II of cell culture was divided into B1(ADMSCs)/B2[ADMSCs+lipopolysaccharide (LPS)]/B3(PrPCOE in ADMSCs)/B4(PrPCOE in ADMSCs+LPS). Sprague-Dawley (SD) rats (n = 50) were equally categorized into groups 1 (sham-operated-control)/2 (IR)/3 (IR+ADMSCs/6.0 × 105 equally divided into bilateral-renal arteries and 6.0 × 105 intravenous administration by 1 h after IR)/4 [IR+PrPCOE-ADMSCs (identical dosage administered as group 3)]/5 [IR+silencing PRNP -ADMSCs (identical dosage administered as group 3)], and kidneys were harvested post-day 3 IR injury.

RESULTS

Part I results demonstrated that the cell viability at 24/48/72 h, BrdU uptake/number of mitDNA/APT concentration/mitochondrial-cytochrome-C+ cells and the protein expressions of ki67/PrPC at 72 h-cell culturing were significantly higher in PrPCOE-ADMSCs than in ADMSCs (all P < 0.001). The protein expressions of oxidative-stress (NOX-1/NOX2/NOX4/oxidized protein)/mitochondrial-damaged (p22-phox/cytosolic-cytochrome-C)/inflammatory (p-NF-κB/IL-1ß/TNF-α/IL-6)/apoptotic (cleaved caspase-3/cleaved-PARP) biomarkers were lowest in A1/A3 and significantly higher in A2 than in A4 (all P < 0.001). Part II result showed that the protein expressions of inflammatory (p-NF-κB/IL-1ß/TNF-α/IL-6)/apoptotic (cleaved caspase-3/cleaved-PARP) biomarkers exhibited an identical pattern of part I among the groups (all P < 0.001). The protein expressions of inflammatory (p-NF-κB/IL-1ß/TNF-α/MMP-9)/oxidative-stress (NOX-1/NOX-2/oxidized-protein)/mitochondrial-damaged (cytosolic-cytochrome-C/p22-phox)/apoptotic (cleaved caspase-3/cleaved-PARP/mitochondrial-Bx)/autophagic (beclin-1/ratio of LC3B-II/LC3B-I)/fibrotic (Smad3/TGF-ß) biomarkers and kidney-injury-score/creatinine level were lowest in group 1, highest in group 2, significantly higher in group 5 than in groups 3/4 (all P < 0.0001).

CONCLUSION

PrPCOE in ADMSCs rejuvenated these cells and played a cardinal role on protecting the kidney against IR injury.

Rejuvenated endothelial progenitor cells through overexpression of cellular prion protein effectively salvaged the critical limb ischemia in rats with preexisting chronic kidney disease

BACKGROUND

This study tested the hypothesis that overexpression of cellular prion protein in endothelial progenitor cells (PrPc^OE-EPCs), defined as "rejuvenated EPCs," was superior to EPCs for salvaging the critical limb ischemia (CLI) induced after 28-day chronic kidney disease (CKD) induction in rat.

METHODS AND RESULTS

Cell viability and flow cytometric analyses of early/late apoptosis/total-intracellular ROS/cell cycle (sub-G1, G2/M phase) were significantly higher in EPCs + H₂O₂ than in EPCs that were significantly reversed in PrPc^OE-EPCs + H₂O₂ (all p < 0.001). The protein expressions of inflammation (IL-1ß/IL-6/MMP-9/p-NF-κB) were significantly increased in EPC + TNF-α than in EPCs that were significantly reversed in PrPc^OE-EPCs + TNF-α (all p < 0.001). Adult-male SD rats (n = 8/each group) were categorized into group 1 (sham-operated control), group 2 (CKD + CLI), group 3 [CKD + CLI + EPCs by intravenous (0.6 × 10⁵)/intra-muscular (0.6 × 10⁵) injections at 3 h after CLI induction], group 4 (CKD + CLI + PrPc^OE-EPCs/dose-administration as group 3) and group 5 (CKD + CLI + siPrnp-EPCs/dose-administration as group 3). By day 14 after CLI induction, the ratio of ischemia to normal blood flow (INBF) in CLI area was highest in group 1/lowest in group 2/significantly higher in group 4 than in groups 3/5 and significantly higher in group 3 than in group 5 (all p < 0.0001). Histopathology demonstrated that the angiogenesis (number of small vessels/CD31 + cells) exhibited a similar trend, whereas the fibrosis/kidney injury score exhibited an opposite pattern of INBF among the groups (all p < 0.0001). The protein expressions of angiogenesis (SDF-1α/VEGF/CXCR4)/cell-stress signaling (p-PI3K/p-Akt/p-m-TOR) were significantly and progressively increased from groups 1-4 that were reversed in group 5 (all p < 0.0001). The protein expressions of fibrotic (p-Smad3/TGF-ß)/oxidative-stress (NOX-1/NOX-2/oxidized-protein)/apoptotic (mitochondrial-Bax/cleaved caspase3/cleaved PARP)/mitochondrial-damaged (cytosolic-cytochrome-C) biomarkers displayed an opposite pattern of INBF among the groups (all p < 0.0001).

CONCLUSION

PrPc^OE-EPCs were superior to EPCs only therapy for salvaging the CLI.