Skeletal muscle possesses a remarkable capacity to regenerate when injured, but when confronted with major traumatic injury resulting in volumetric muscle loss (VML), the regenerative process consistently fails. The loss of muscle tissue and function from VML injury has prompted development of a suite of therapeutic approaches but these strategies have proceeded without a comprehensive understanding of the molecular landscape that drives the injury response. Herein, we administered a VML injury in an established rodent model and monitored the evolution of the healing phenomenology over multiple time points using muscle function testing, histology, and expression profiling by RNA sequencing. The injury response was then compared to a regenerative medicine treatment using orthotopic transplantation of autologous minced muscle grafts (~1?mm3 tissue fragments). A chronic inflammatory and fibrotic response was observed at all time points following VML. These results suggest that the pathological response to VML injury during the acute stage of the healing response overwhelms endogenous and therapeutic regenerative processes. Overall, the data presented delineate key molecular characteristics of the pathobiological response to VML injury that are critical effectors of effective regenerative treatment paradigms. Overall design: RNA-Seq time couse of muscle volumetric muscle loss injury healing with controls
Multiscale analysis of a regenerative therapy for treatment of volumetric muscle loss injury.
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View SamplesThe mechanisms underlying muscle wasting in cancer patients remain poorly understood, and consequently there remains an unmet clinical need for new biomarkers and treatment strategies.
Suppression of skeletal muscle turnover in cancer cachexia: evidence from the transcriptome in sequential human muscle biopsies.
Sex, Age, Specimen part
View SamplesWarfare has long been associated with traumatic brain injury (TBI) in militarized zones. Common forms of TBI can be caused by a physical insult to the head-brain or by the effects of a high velocity blast shock wave generated by the detonation of an explosive device. While both forms of trauma are distinctly different regarding the mechanism of trauma induction, there are striking similarities in the cognitive and emotional status of survivors. Presently, proven effective therapeutics for the treatment of either form of TBI are unavailable. To be able to develop efficacious therapies, studies involving animal models of physical- and blast-TBI are required to identify possible novel or existing medicines that may be of value in the management of clinical events. We examined indices of cognition and anxiety-like behavior and the hippocampal gene transcriptome of mice subjected to both forms of TBI. We identified common behavioral deficits and gene expression regulations, in addition to unique injury-specific forms of gene regulation. Molecular pathways presented a pattern similar to that seen in gene expression. Interestingly, pathways connected to Alzheimers disease displayed a markedly different form of regulation depending on the type of TBI. While these data highlight similarities in behavioral outcomes after trauma, the divergence in hippocampal transcriptome observed between models suggests that, at the molecular level, the TBIs are quite different. These models may provide tools to help define therapeutic approaches for the treatment of physical- and blast-TBIs. Based upon observations of increasing numbers of personnel displaying TBI related emotional and behavioral changes in militarized zones, the development of efficacious therapies will become a national if not a global priority.
Changes in mouse cognition and hippocampal gene expression observed in a mild physical- and blast-traumatic brain injury.
Sex, Specimen part, Treatment, Time
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Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesTelomerase, the essential enzyme that maintains telomere length, contains two core components, TERT and TR. While early studies in yeast and mouse both indicated that loss of telomerase leads to phenotypes that arise after an increased number of generations, due to telomere shortening, recent studies claim additional roles for telomerase components in transcription and the response to DNA damage. To test these telomere length maintenance-independent roles of telomerase components, we examined first generation mTR-/- and mTERT-/- mice with long telomeres. We used gene expression profiling and found no genes that were expressed at significantly different levels when independent mTR-/- G1 mice were compared to mTERT-/- G1 mice and to wild-type mice. In addition, we compared the response to DNA damage in mTR-/-G1 and mTERT-/- G1 mouse embryonic fibroblasts, and found no increase in the response to DNA damage in the absence of either telomerase components compared to wild-type. We conclude that in the wild-type physiological telomere length setting, neither mTR nor mTERT act as a transcription factor or have a role in the DNA damage response.
Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesTelomerase, the essential enzyme that maintains telomere length, contains two core components, TERT and TR. While early studies in yeast and mouse both indicated that loss of telomerase leads to phenotypes that arise after an increased number of generations, due to telomere shortening, recent studies claim additional roles for telomerase components in transcription and the response to DNA damage. To test these telomere length maintenance-independent roles of telomerase components, we examined first generation mTR-/- and mTERT-/- mice with long telomeres. We used gene expression profiling and found no genes that were expressed at significantly different levels when independent mTR-/- G1 mice were compared to mTERT-/- G1 mice and to wild-type mice. In addition, we compared the response to DNA damage in mTR-/-G1 and mTERT-/- G1 mouse embryonic fibroblasts, and found no increase in the response to DNA damage in the absence of either telomerase components compared to wild-type. We conclude that in the wild-type physiological telomere length setting, neither mTR nor mTERT act as a transcription factor or have a role in the DNA damage response.
Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Blast traumatic brain injury-induced cognitive deficits are attenuated by preinjury or postinjury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4.
Sex, Specimen part, Treatment, Time
View SamplesBlast traumatic brain injury (B-TBI) affects military and civilian personnel. Presently there are no approved drugs for blast brain injury. Exendin-4, administered subcutaneously, was evaluated as a pre-treatment (48 hours) and post-injury treatment (2 hours) on neurodegeneration, behaviors and gene expressions in a murine open field model of blast injury. B-TBI induced neurodegeneration, changes in cognition and genes expressions linked to dementia disorders. Exendin-4, administered pre- or post-injury ameliorated B-TBI-induced neurodegeneration at 72 hours, memory deficits from days 7-14 and attenuated genes regulated by blast at day 14 post-injury. The present data suggest shared pathological processes between concussive and B-TBI, with endpoints amenable to beneficial therapeutic manipulation by exendin-4. B-TBI-induced dementia-related gene pathways and cognitive deficits in mice somewhat parallel epidemiological studies of Barnes and co-workers who identified a greater risk in US military veterans who experienced diverse TBIs, for dementia in later life.
Blast traumatic brain injury-induced cognitive deficits are attenuated by preinjury or postinjury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4.
Sex, Specimen part
View SamplesTraumatic brain injury (TBI) is a global problem reaching near epidemic numbers that manifests clinically with cognitive problems that decades later may result in dementias like Alzheimers disease (AD). Presently, little can be done to prevent ensuing neurological dysfunctions by pharmacological means. Recently, it has become apparent that several CNS diseases share common terminal features of neuronal cell death. The effects of exendin-4 (Ex-4), a neuroprotective agent delivered via a subcutaneous micro-osmotic pump, were examined in the setting of mild TBI (mTBI). Utilizing a model of mTBI, where cognitive disturbances occur over time, animals were subjected to four treatments: sham; Ex-4; mTBI and Ex-4/mTBI. mTBI mice displayed deficits in novel object recognition, while Ex-4/mTBI mice performed similar to sham. Hippocampal gene expression, assessed by gene array methods, showed significant differences with little overlap in co-regulated genes between groups. Importantly, changes in gene expression induced by mTBI, including genes associated with AD were largely prevented by Ex-4. These data suggest a strong beneficial action of Ex-4 in managing secondary events induced by a traumatic brain injury.
Exendin-4, a glucagon-like peptide-1 receptor agonist prevents mTBI-induced changes in hippocampus gene expression and memory deficits in mice.
Sex, Specimen part, Treatment, Time
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DAF-16/FOXO and EGL-27/GATA promote developmental growth in response to persistent somatic DNA damage.
Treatment
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