ARMMs as a versatile platform for intracellular delivery of macromolecules.

Majority of disease-modifying therapeutic targets are restricted to the intracellular space and are therefore not druggable using existing biologic modalities. The ability to efficiently deliver macromolecules inside target cells or tissues would greatly expand the current landscape of therapeutic targets for future generations of biologic drugs, but remains challenging. Here we report the use of extracellular vesicles, known as arrestin domain containing protein 1 [ARRDC1]-mediated microvesicles (ARMMs), for packaging and intracellular delivery of a myriad of macromolecules, including the tumor suppressor p53 protein, RNAs, and the genome-editing CRISPR-Cas9/guide RNA complex.

A Circulating microRNA Signature Predicts Age-Based Development of Lymphoma.

Extensive epidemiological data have demonstrated an exponential rise in the incidence of non-Hodgkin lymphoma (NHL) that is associated with increasing age. The molecular etiology of this remains largely unknown, which impacts the effectiveness of treatment for patients. We proposed that age-dependent circulating microRNA (miRNA) signatures in the host influence diffuse large B cell lymphoma (DLBCL) development.

Individual substitution mutations in the AID C terminus that ablate IgH class switch recombination.

Activation-induced cytidine deaminase (AID) is essential for class switch recombination (CSR) and somatic hypermutation (SHM) of Ig genes. The C terminus of AID is required for CSR but not for SHM, but the reason for this is not entirely clear. By retroviral transduction of mutant AID proteins into aid-/- mouse splenic B cells, we show that 4 amino acids within the C terminus of mouse AID, when individually mutated to specific amino acids (R190K, A192K, L196S, F198S), reduce CSR about as much or more than deletion of the entire C terminal 10 amino acids.

Mismatch repair proteins and AID activity are required for the dominant negative function of C-terminally deleted AID in class switching.

Activation-induced cytidine deaminase (AID) is essential for class-switch recombination (CSR) and somatic hypermutation (SHM) of Ig genes. The AID C terminus is required for CSR, but not for S-region DNA double-strand breaks (DSBs) during CSR, and it is not required for SHM. AID lacking the C terminus (ΔAID) is a dominant negative (DN) mutant, because human patients heterozygous for this mutant fail to undergo CSR.

Differential expression of APE1 and APE2 in germinal centers promotes error-prone repair and A:T mutations during somatic hypermutation.

Somatic hypermutation (SHM) of antibody variable region genes is initiated in germinal center B cells during an immune response by activation-induced cytidine deaminase (AID), which converts cytosines to uracils. During accurate repair in nonmutating cells, uracil is excised by uracil DNA glycosylase (UNG), leaving abasic sites that are incised by AP endonuclease (APE) to create single-strand breaks, and the correct nucleotide is reinserted by DNA polymerase β. During SHM, for unknown reasons, repair is error prone.