Biology subjects

Silvestri, G.

Publications and source records attributed to Silvestri, G..

2 recordsLinked to original sources

bioRxiv2018

Dysregulation of circular RNAs in myotonic dystrophy type 1

Circular RNAs (circRNAs) constitute a recently re-discovered class of non-coding RNAs functioning as sponge for miRNAs and proteins, affecting RNA splicing and regulating transcription. CircRNAs are generated by \"back-splicing\", linking covalently 3- and 5-ends of exons. Thus, circRNA levels might be deregulated in conditions associated to altered RNA-splicing. Indeed, increasing evidence indicates their role in human diseases. Specifically, myotonic dystrophy type 1 (DM1) is a multisystemic disorder caused by expanded CTG-repeats in the DMPK gene, resulting in abnormal mRNA-splicing. In this investigation, circRNAs expressed in DM1 skeletal muscles were identified by analyzing RNA-sequencing data-sets followed by qPCR validation. In muscle biopsies, out of 9 tested, 4 transcripts showed an increased circular fraction: CDYL, HIPK3, RTN4_03 and ZNF609. The circular fraction values correlated positively with skeletal muscle strength and Receiver-Operating-Characteristics curves showed that these four circRNAs allow to distinguish DM1 patients from controls. The identified circRNAs were also detectable in peripheral-blood-mononuclear-cells (PBMCs) and plasma of DM1 patients, but they were not regulated significantly, indicating a tissue-selectivity of the identified modulations. Finally, increased circular fractions of RTN4_03 and ZNF609 were also observed in differentiated myogenic cell lines derived from DM1 patients.\n\nIn conclusion, this proof-of-principle study identified circRNA dysregulation in DM1 patients.

molecular biology↗

bioRxiv2018

Slow delivery immunization enhances HIV neutralizing antibody and germinal center responses via modulation of immunodominance

The observation that humans can produce broadly neutralizing antibodies (bnAbs) against HIV-1 has generated enthusiasm about the potential for a bnAb vaccine against HIV-1. Conventional immunization strategies will likely be insufficient for the development of a bnAb HIV vaccine and vaccines to other difficult pathogens, due to the significant immunological hurdles posed, including B cell immunodominance and germinal center (GC) quantity and quality. Using longitudinal lymph node fine needle aspirates, we found that two independent methods of slow delivery immunization of rhesus macaques (RM) resulted in larger GCs, more robust and sustained GC Tfh cell responses, and GC B cells with improved Env-binding, which correlated with the development of ~20 to 30-fold higher titers of tier 2 HIV-1 nAbs. Using a new RM genomic immunoglobulin loci reference sequence, we identified differential IgV gene usage between slow delivery immunized and conventional bolus immunized animals. The most immunodominant IgV gene used by conventionally immunized animals was associated with many GC B cell lineages. Ab mapping of those GC B cell specificities demonstrated targeting of an immunodominant non-neutralizing trimer base epitope, while that response was muted in slow delivery immunized animals. Thus, alternative immunization strategies appear to enhance nAb development by altering GCs and modulating immunodominance of non-neutralizing epitopes.

immunology↗