Intracellular Delivery of Plasmid DNA Using Amphipathic Helical Cell-Penetrating Peptides Containing Dipropylglycine.

Cell-penetrating peptides (CPPs) serve as potent vehicles for delivering membrane-impermeable compounds, including nucleic acids, into cells. In a previous study, we reported the successful intracellular delivery of small interfering RNAs (siRNAs) with negligible cytotoxicity using a peptide containing an unnatural amino acid (dipropylglycine). In the present study, we employed the same seven peptides as the previous study to evaluate their efficacy in delivering plasmid DNA (pDNA) intracellularly. Although pDNA and siRNA are nucleic acids, they differ in size and biological function, which may influence the optimal peptide sequences for their delivery. Herein, three peptides demonstrated effective pDNA transfection abilities. Notably, only one of the three peptides previously exhibited efficient gene-silencing effect with siRNA. These findings validate our hypothesis and offer insights for the personalized design of CPPs for the delivery of pDNA and siRNA.

An Amphipathic Structure of a Dipropylglycine-Containing Helical Peptide with Sufficient Length Enables Safe and Effective Intracellular siRNA Delivery.

Amphipathic peptides composed of cationic amino acids and hydrophobic amino acids have cell-penetrating ability and are often used as a delivery tool for membrane-impermeable compounds. Small interfering RNA (siRNAs) are one of the delivery targets for such cell-penetrating peptides (CPPs). Cationic CPPs can associate with anionic siRNAs by electrostatic interactions resulting in the formation of nano-sized complexes, which can deliver siRNAs intracellularly. CPPs containing unnatural amino acids offer promising tools to siRNA delivery. However, the detailed structure-activity relationship in siRNA delivery has been rarely studied. In the current study, we designed peptides containing dipropylglycine (Dpg) and explored the cellular uptake and cytotoxicity of peptide/siRNA complexes. The amphipathic structure of the peptides played a key role in complexation with siRNAs and intracellular siRNA delivery. In the amphipathic peptides, cellular uptake of siRNA increased with increasing peptide length, but cytotoxicity was reduced. A peptide containing four Dpg exhibited an effective gene-silencing effect with small amounts of peptides without cytotoxicity in medium containing serum. These findings will be helpful for the design of novel CPPs for siRNA delivery.

Neuroimaging in cerebral small vessel disease: Update and new concepts / Neuroimagem na doença de pequenos vasos cerebrais: atualização e novos conceitos

ABSTRACT. In recent years, small vessel disease (SVD) has been recognized for its major impact on cognitive impairment in elderly people, where it is often difficult to separate its effects from those of neurodegenerative diseases individually. SVD is a systemic disease, probably related to diffuse endothelial dysfunction, which affects the perforating arterioles, capillaries and venules in the brain. Although often asymptomatic, it is responsible for almost half of all dementia cases and a significant proportion of stroke cases. Imaging features found on magnetic resonance include recent small subcortical infarctions, lacunes of presumed vascular origin, white matter hyperintensity of presumed vascular origin, prominent perivascular spaces and cerebral microbleeds. The recognition of these imaging findings as a spectrum of the same disease caused by endothelial dysfunction of small cerebral vessels can allow an overall analysis of the disease and thus the development of more effective preventive and therapeutic strategies.

RESUMO. Nos últimos anos, a doença de pequenos vasos cerebrais (DPV) tem sido reconhecida por seu grande impacto no comprometimento cognitivo em pacientes mais velhos, sendo muitas vezes difícil separar os efeitos dela e das doenças neurodegenerativas individualmente. Trata-se de uma doença sistêmica, provavelmente relacionada com uma disfunção endotelial difusa, que no encéfalo acomete preferencialmente as arteríolas perfurantes, capilares e vênulas. Apesar de muitas vezes ser assintomática, é responsável por quase metade dos casos de demência e por uma parcela importante dos acidentes vasculares encefálicos. Os achados de neuroimagem encontrados na ressonância magnética incluem pequenos infartos subcorticais recentes, lacunas de origem vascular presumida, hipersinal da substância branca de origem vascular presumida, alargamento dos espaços perivasculares e micro-hemorragias. O reconhecimento desses achados de imagem como espectro de uma mesma doença ocasionada pela disfunção endotelial dos pequenos vasos cerebrais possivelmente permitirá uma análise global da doença e com isso o desenvolvimento de estratégias preventivas e terapêuticas mais eficazes.

Neuroimaging in cerebral small vessel disease: Update and new concepts.

In recent years, small vessel disease (SVD) has been recognized for its major impact on cognitive impairment in elderly people, where it is often difficult to separate its effects from those of neurodegenerative diseases individually. SVD is a systemic disease, probably related to diffuse endothelial dysfunction, which affects the perforating arterioles, capillaries and venules in the brain. Although often asymptomatic, it is responsible for almost half of all dementia cases and a significant proportion of stroke cases. Imaging features found on magnetic resonance include recent small subcortical infarctions, lacunes of presumed vascular origin, white matter hyperintensity of presumed vascular origin, prominent perivascular spaces and cerebral microbleeds. The recognition of these imaging findings as a spectrum of the same disease caused by endothelial dysfunction of small cerebral vessels can allow an overall analysis of the disease and thus the development of more effective preventive and therapeutic strategies.

Nos últimos anos, a doença de pequenos vasos cerebrais (DPV) tem sido reconhecida por seu grande impacto no comprometimento cognitivo em pacientes mais velhos, sendo muitas vezes difícil separar os efeitos dela e das doenças neurodegenerativas individualmente. Trata-se de uma doença sistêmica, provavelmente relacionada com uma disfunção endotelial difusa, que no encéfalo acomete preferencialmente as arteríolas perfurantes, capilares e vênulas. Apesar de muitas vezes ser assintomática, é responsável por quase metade dos casos de demência e por uma parcela importante dos acidentes vasculares encefálicos. Os achados de neuroimagem encontrados na ressonância magnética incluem pequenos infartos subcorticais recentes, lacunas de origem vascular presumida, hipersinal da substância branca de origem vascular presumida, alargamento dos espaços perivasculares e micro-hemorragias. O reconhecimento desses achados de imagem como espectro de uma mesma doença ocasionada pela disfunção endotelial dos pequenos vasos cerebrais possivelmente permitirá uma análise global da doença e com isso o desenvolvimento de estratégias preventivas e terapêuticas mais eficazes.