c-kit Haploinsufficiency impairs adult cardiac stem cell growth, myogenicity and myocardial regeneration

An overdose of Isoproterenol (ISO) causes acute cardiomyocyte (CM) dropout and activates the resident cardiac c-kitpos stem/progenitor cells (CSCs) generating a burst of new CM formation that replaces those lost to ISO. Recently, unsuccessful attempts to reproduce these findings using c-kitCre knock-in (KI) mouse models were reported. We tested whether c-kit haploinsufficiency in c-kitCreKI mice was the cause of the discrepant results in response to ISO. Male C57BL/6J wild-type (wt) mice and c-kitCreKI mice were given a single dose of ISO (200 and/or 400 mg/Kg s.c.). CM formation was measured with different doses and duration of BrdU or EdU. We compared the myogenic and regenerative potential of the c-kitCreCSCs with wtCSCs. Acute ISO overdose causes LV dysfunction with dose-dependent CM death by necrosis and apoptosis, whose intensity follows a basal-apical and epicardium to sub-endocardium gradient, with the most severe damage confined to the apical sub-endocardium. The damage triggers significant new CM formation mainly in the apical sub-endocardial layer. c-kit haploinsufficiency caused by c-kitCreKIs severely affects CSCs myogenic potential. c-kitCreKI mice post-ISO fail to respond with CSC activation and show reduced CM formation and suffer chronic cardiac dysfunction. Transplantation of wtCSCs rescued the defective regenerative cardiac phenotype of c-kitCreKI mice. Furthermore, BAC-mediated transgenesis of a single c-kit gene copy normalized the functional diploid c-kit content of c-kitCreKI CSCs and fully restored their regenerative competence. Overall, these data show that c-kit haploinsufficiency impairs the endogenous cardioregenerative response after injury affecting CSC activation and CM replacement. Repopulation of c-kit haploinsufficient myocardial tissue with wtCSCs as well c-kit gene deficit correction of haploinsufficient CSCs restores CM replacement and functional cardiac repair. Thus, adult neo-cardiomyogenesis depends on and requires a diploid level of c-kit

Supplementary Table 4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Table 4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p

Supplementary Table 1 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Table 1 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p

Supplementary Table 1 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Table 1 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p

Data from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

&lt;div&gt;Abstract&lt;p&gt;Glioblastoma is classified into two subtypes on the basis of clinical history: “primary glioblastoma” arising &lt;i&gt;de novo&lt;/i&gt; without detectable antecedent disease and “secondary glioblastoma” evolving from a low-grade astrocytoma. Despite their distinctive clinical courses, they arrive at an indistinguishable clinical and pathologic end point highlighted by widespread invasion and resistance to therapy and, as such, are managed clinically as if they are one disease entity. Because the life history of a cancer cell is often reflected in the pattern of genomic alterations, we sought to determine whether primary and secondary glioblastomas evolve through similar or different molecular pathogenetic routes. Clinically annotated primary and secondary glioblastoma samples were subjected to high-resolution copy number analysis using oligonucleotide-based array comparative genomic hybridization. Unsupervised classification using genomic nonnegative matrix factorization methods identified three distinct genomic subclasses. Whereas one corresponded to clinically defined primary glioblastomas, the remaining two stratified secondary glioblastoma into two genetically distinct cohorts. Thus, this global genomic analysis showed wide-scale differences between primary and secondary glioblastomas that were previously unappreciated, and has shown for the first time that secondary glioblastoma is heterogeneous in its molecular pathogenesis. Consistent with these findings, analysis of regional recurrent copy number alterations revealed many more events unique to these subclasses than shared. The pathobiological significance of these shared and subtype-specific copy number alterations is reinforced by their frequent occurrence, resident genes with clear links to cancer, recurrence in diverse cancer types, and apparent association with clinical outcome. We conclude that glioblastoma is composed of at least three distinct molecular subtypes, including novel subgroups of secondary glioblastoma, which may benefit from different therapeutic strategies. (Cancer Res 2006; 66(23): 11502-13)&lt;/p&gt;&lt;/div&gt;</jats:p

Supplementary Figures 1-4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Figures 1-4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p

Supplementary Figures 1-4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Figures 1-4 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p

Data from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

&lt;div&gt;Abstract&lt;p&gt;Glioblastoma is classified into two subtypes on the basis of clinical history: “primary glioblastoma” arising &lt;i&gt;de novo&lt;/i&gt; without detectable antecedent disease and “secondary glioblastoma” evolving from a low-grade astrocytoma. Despite their distinctive clinical courses, they arrive at an indistinguishable clinical and pathologic end point highlighted by widespread invasion and resistance to therapy and, as such, are managed clinically as if they are one disease entity. Because the life history of a cancer cell is often reflected in the pattern of genomic alterations, we sought to determine whether primary and secondary glioblastomas evolve through similar or different molecular pathogenetic routes. Clinically annotated primary and secondary glioblastoma samples were subjected to high-resolution copy number analysis using oligonucleotide-based array comparative genomic hybridization. Unsupervised classification using genomic nonnegative matrix factorization methods identified three distinct genomic subclasses. Whereas one corresponded to clinically defined primary glioblastomas, the remaining two stratified secondary glioblastoma into two genetically distinct cohorts. Thus, this global genomic analysis showed wide-scale differences between primary and secondary glioblastomas that were previously unappreciated, and has shown for the first time that secondary glioblastoma is heterogeneous in its molecular pathogenesis. Consistent with these findings, analysis of regional recurrent copy number alterations revealed many more events unique to these subclasses than shared. The pathobiological significance of these shared and subtype-specific copy number alterations is reinforced by their frequent occurrence, resident genes with clear links to cancer, recurrence in diverse cancer types, and apparent association with clinical outcome. We conclude that glioblastoma is composed of at least three distinct molecular subtypes, including novel subgroups of secondary glioblastoma, which may benefit from different therapeutic strategies. (Cancer Res 2006; 66(23): 11502-13)&lt;/p&gt;&lt;/div&gt;</jats:p

Supplementary Table 2 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities

Supplementary Table 2 from Marked Genomic Differences Characterize Primary and Secondary Glioblastoma Subtypes and Identify Two Distinct Molecular and Clinical Secondary Glioblastoma Entities</jats:p