miR-9-5p is Downregulated in Serum Extracellular Vesicles of Patients Treated with Biperiden After Traumatic Brain Injury.

Traumatic brain injury (TBI) is a prevalent and debilitating condition, which often leads to the development of post-traumatic epilepsy (PTE), a condition that yet lacks preventive strategies. Biperiden, an anticholinergic drug, is a promising candidate that has shown efficacy in murine models of PTE. MicroRNAs (miRNAs), small regulatory RNAs, can help in understanding the biological basis of PTE and act as TBI- and PTE-relevant biomarkers that can be detected peripherally, as they are present in extracellular vesicles (EVs) that cross the blood-brain barrier. This study aimed to investigate miRNAs in serum EVs from patients with TBI, and their association with biperiden treatment and PTE. Blood samples of 37 TBI patients were collected 10 days after trauma and treatment initiation in a double-blind clinical trial. A total of 18 patients received biperiden, with three subjects developing PTE, and 19 received placebo, with two developing PTE. Serum EVs were characterized by size distribution and protein profiling, followed by high-throughput sequencing of the EV miRNome. Differential expression analysis revealed no significant differences in miRNA expression between TBI patients with and without PTE. Interestingly, miR-9-5p displayed decreased expression in biperiden-treated patients compared to the placebo group. This miRNA regulates genes enriched in stress response pathways, including axonogenesis and neuronal death, relevant to both PTE and TBI. These findings indicate that biperiden may alter miR-9-5p expression in serum EVs, which may play a role in TBI resolution.

Neurovascular dysfunction and neuroinflammation in a Cockayne syndrome mouse model.

Cockayne syndrome (CS) is a rare, autosomal genetic disorder characterized by premature aging-like features, such as cachectic dwarfism, retinal atrophy, and progressive neurodegeneration. The molecular defect in CS lies in genes associated with the transcription-coupled branch of the nucleotide excision DNA repair (NER) pathway, though it is not yet clear how DNA repair deficiency leads to the multiorgan dysfunction symptoms of CS. In this work, we used a mouse model of severe CS with complete loss of NER (Csa-/-/Xpa-/-), which recapitulates several CS-related phenotypes, resulting in premature death of these mice at approximately 20 weeks of age. Although this CS model exhibits a severe progeroid phenotype, we found no evidence of in vitro endothelial cell dysfunction, as assessed by measuring population doubling time, migration capacity, and ICAM-1 expression. Furthermore, aortas from CX mice did not exhibit early senescence nor reduced angiogenesis capacity. Despite these observations, CX mice presented blood brain barrier disruption and increased senescence of brain endothelial cells. This was accompanied by an upregulation of inflammatory markers in the brains of CX mice, such as ICAM-1, TNFα, p-p65, and glial cell activation. Inhibition of neovascularization did not exacerbate neither astro- nor microgliosis, suggesting that the pro-inflammatory phenotype is independent of the neurovascular dysfunction present in CX mice. These findings have implications for the etiology of this disease and could contribute to the study of novel therapeutic targets for treating Cockayne syndrome patients.

Transcription blockage by DNA damage in nucleotide excision repair-related neurological dysfunctions.

Human genetic syndromes deficient in nucleotide excision repair (NER), such as xeroderma pigmentosum and Cockayne syndrome, may present neurological abnormalities and premature aging symptoms. Unrepaired endogenously generated DNA damage that hampers transcription is a strong candidate that contributes to the development of these severe effects in neuronal tissue. Endogenous lesions include those generated due to byproducts of cellular metabolisms, such as reactive oxygen species. This review presents much of the evidence on the mechanisms related to neurodegenerative processes associated with DNA damage responses. The primary focus is on the effects of the transcription machinery, including the accumulation of DNA•RNA hybrids (R-loops) that, in turn, influence DNA damage and repair metabolism. Moreover, several neuronal tissues present higher expression of long genes, a genomic subset more affected by DNA lesions, which may explain part of the neurological abnormalities in these patients. Also, neuronal tissues have different DNA repair capabilities that might result in different neurological consequences, as observed in patients and NER deficient animal models. The better understanding of how the accumulation of transcription blocking lesions can lead to neurological abnormalities and premature aging-like phenotypes may assist us in finding potential biomarkers and therapeutic targets that might improve the lives of these patients, as well as other neurological disorders in the general population.

Cockayne Syndrome: The many challenges and approaches to understand a multifaceted disease.

The striking and complex phenotype of Cockayne syndrome (CS) patients combines progeria-like features with developmental deficits. Since the establishment of the in vitro culture of skin fibroblasts derived from patients with CS in the 1970s, significant progress has been made in the understanding of the genetic alterations associated with the disease and their impact on molecular, cellular, and organismal functions. In this review, we provide a historic perspective on the research into CS by revisiting seminal papers in this field. We highlighted the great contributions of several researchers in the last decades, ranging from the cloning and characterization of CS genes to the molecular dissection of their roles in DNA repair, transcription, redox processes and metabolism control. We also provide a detailed description of all pathological mutations in genes ERCC6 and ERCC8 reported to date and their impact on CS-related proteins. Finally, we review the contributions (and limitations) of many genetic animal models to the study of CS and how cutting-edge technologies, such as cell reprogramming and state-of-the-art genome editing, are helping us to address unanswered questions.

Biomass burning in the Amazon region causes DNA damage and cell death in human lung cells.

Most of the studies on air pollution focus on emissions from fossil fuel burning in urban centers. However, approximately half of the world's population is exposed to air pollution caused by biomass burning emissions. In the Brazilian Amazon population, over 10 million people are directly exposed to high levels of pollutants resulting from deforestation and agricultural fires. This work is the first study to present an integrated view of the effects of inhalable particles present in emissions of biomass burning. Exposing human lung cells to particulate matter smaller than 10 µm (PM10), significantly increased the level of reactive oxygen species (ROS), inflammatory cytokines, autophagy, and DNA damage. Continued PM10 exposure activated apoptosis and necrosis. Interestingly, retene, a polycyclic aromatic hydrocarbon present in PM10, is a potential compound for the effects of PM10, causing DNA damage and cell death. The PM10 concentrations observed during Amazon biomass burning were sufficient to induce severe adverse effects in human lung cells. Our study provides new data that will help elucidate the mechanism of PM10-mediated lung cancer development. In addition, the results of this study support the establishment of new guidelines for human health protection in regions strongly impacted by biomass burning.

NRF2 and glutathione are key resistance mediators to temozolomide in glioma and melanoma cells.

Cancer is a leading cause of death worldwide, and while great advances have been made particularly in chemotherapy, many types of cancer still present a dismal prognosis. In the case of glioma, temozolomide (TMZ) is the main option for treatment, but it has limited success due to drug resistance. While this resistance is usually associated to DNA repair mechanisms, in this work we demonstrate that oxidative stress plays an important role. We showed that upon TMZ treatment there is an induction of the nuclear factor erythroid 2-related factor 2 (NRF2), which is the main antioxidant transcription factor regulator in human cells. This is accompanied by an enhancement of glutathione (GSH) concentration in the tumor cells. The effectiveness of this pathway was proven by silencing NFR2, which greatly enhanced cell death upon TMZ treatment both in vitro and in vivo. Also, higher DNA damage and induced cell death was observed by combining BSO - a GSH inhibitor - with TMZ. Similar effects were also observed using in vitro and in vivo models of melanoma, thus possibly indicating that GSH has a decisive role in TMZ resistance in a wider range of tumors. Thus, a combined regimen of BSO and TMZ configures an interesting therapeutic alternative for fighting both glioma and melanoma.