Cultured human amniocytes express hTERT, which is distributed between nucleus and cytoplasm and is secreted in extracellular vesicles.

BACKGROUND: An increasing number of studies on stem cells suggests that the therapeutic effect they exert is primarily mediated by a paracrine regulation through extracellular vesicles (EVs) giving solid grounds for stem cell EVs to be exploited as agents for treating diseases or for restoring damaged tissues and organs. Due to their capacity to differentiate in all embryonic germ layers, amniotic fluid stem cells (AFCs), represent a highly promising cell type for tissue regeneration, which however is still poorly studied and in turn underutilized. In view of this, we conducted a first investigation on the expression of human hTERT gene - known to be among the key triggers of organ regeneration - in AFCs and in the EVs they secrete. METHODS: Isolated AFCs were evaluated by RT-qPCR for hTERT expression. The clones expressing the highest levels of transcript, were analyzed by Immunofluorescence imaging and Nuclear/cytoplasmic fractionation in order to evaluate hTERT subcellular localization. We then separated EVs from FBS depleted culture medium by serial (ultra) centrifugations steps and characterized them using Western blotting, Atomic force Microscopy and Nanoplasmonic assay. RESULTS: We first demonstrated that primary cultures of AFCs express the gene hTERT at different levels. Then we evidenced that in AFCs with the higher transcript levels, the hTERT protein is present in the nuclear and cytoplasmic compartment. Finally, we found that cytosolic hTERT is embodied in the EVs that AFCs secrete in the extracellular milieu. CONCLUSIONS: Our study demonstrates for the first time the expression of the full protein hTERT by AFCs and its release outside the cell mediated by EVs, indicating a new extra telomeric role for this protein. This finding represents an initial but crucial evidence for considering AFCs derived EVs as new potential sources for tissue regeneration.

SNP array and FISH analysis of a proband with a 22q13.2- 22qter duplication shed light on the molecular origin of the rearrangement.

BACKGROUND: In about one third of healthy subjects, the microscopic analysis of chromosomes reveals heteromorphisms with no clinical implications: for example changes in size of the short arm of acrocentric chromosomes. In patients with a pathological phenotype, however, a large acrocentric short arm can mask a genomic imbalance and should be investigated in more detail. We report the first case of a chromosome 22 with a large acrocentric short arm masking a partial trisomy of the distal long arm, characterized by SNP array. We suggest a possible molecular mechanism underlying the rearrangement. CASE PRESENTATION: We report the case of a 15-year-old dysmorphic girl with low grade psychomotor retardation characterized by a karyotype with a large acrocentric short arm of one chromosome 22. Cytogenetic analysis revealed a normal karyotype with a very intense Q-fluorescent and large satellite on the chromosome 22 short arm. Fluorescence in situ hybridisation analysis showed a de novo partial trisomy of the 22q13.2-qter chromosome region attached to the short arm of chromosome 22. SNP-array analysis showed that the duplication was 8.5 Mb long and originated from the paternal chromosome. Haplotype analysis revealed that the two paternal copies of the distal part of chromosome 22 have the same haplotype and, therefore, both originated from the same paternal chromosome 22. A possible molecular mechanism that could explain this scenario is a break-induced replication (BIR) which is involved in non-reciprocal translocation events. CONCLUSION: The combined use of FISH and SNP arrays was crucial for a better understanding of the molecular mechanism underlying this rearrangement. This strategy could be applied for a better understanding of the molecular mechanisms underlying cryptic chromosomal rearrangements.

Generation of induced pluripotent stem cells (iPSCs) from patient with Cri du Chat Syndrome.

The Cri du Chat Syndrome (CdCS) is a genetic disease resulting from variable size deletion occurring on the short arm of chromosome 5. The main clinical features are a high-pitched monochromatic cry, microcephaly, severe psychomotor and mental retardation with characteristics of autism spectrum disorders such as hand flapping, obsessive attachments to objects, twirling objects, repetitive movements, and rocking. We reprogrammed to pluripotency peripheral blood mononuclear cells derived from a patient carrying large deletion on the short arm of chromosome 5, using a commercially available non-integrating expression system. The iPSCs expressed pluripotency markers and differentiated in the three embryonic germ layers.

Generation of three isogenic induced Pluripotent Stem Cell lines (iPSCs) from fibroblasts of a patient with Aicardi Goutières Syndrome carrying a c.2471G>A dominant mutation in IFIH1 gene.

Aicardi-Goutières syndrome (AGS) is an early-onset monogenic encephalopathy characterized by intracranial calcification, leukodystrophy and cerebrospinal fluid lymphocytosis. To date, seven genes have been related to AGS. Among these, IFIH1 encodes for MDA5, a cytosolic double-stranded RNA receptor, and is responsible for AGS type 7. We generated three isogenic iPSC clones, using a Sendai virus-based vector, starting from fibroblasts of a patient carrying a dominant mutation in IFIH1. All lines were characterized for genomic integrity, genetic uniqueness, pluripotency, and differentiation capability. Our clones might offer a good model to investigate AGS7 pathophysiological mechanism and to discover new biomarkers for this condition treatment.

Establishment of three iPSC lines from fibroblasts of a patient with Aicardi Goutières syndrome mutated in RNaseH2B.

We report the generation of three isogenic iPSC clones (UNIBSi007-A, UNIBSi007-B, and UNIBSi007-C) obtained from fibroblasts of a patient with Aicardi Goutières Syndrome (AGS) carrying a homozygous mutation in RNaseH2B. Cells were transduced using a Sendai virus based system, delivering the human OCT4, SOX2, c-MYC and KLF4 transcription factors. The resulting transgene-free iPSC lines retained the disease-causing DNA mutation, showed normal karyotype, expressed pluripotent markers and could differentiate in vitro toward cells of the three embryonic germ layers.

Generation of three iPSC lines from fibroblasts of a patient with Aicardi Goutières Syndrome mutated in TREX1.

Fibroblasts from a patient with Aicardi Goutières Syndrome (AGS) carrying a compound heterozygous mutation in TREX1, were reprogrammed into induced pluripotent stem cells (iPSCs) to establish isogenic clonal stem cell lines: UNIBSi006-A, UNIBSi006-B, and UNIBSi006-C. Cells were transduced using the episomal Sendai viral vectors, containing human OCT4, SOX2, c-MYC and KLF4 transcription factors. The transgene-free iPSC lines showed normal karyotype, expressed pluripotent markers and displayed in vitro differentiation potential toward cells of the three embryonic germ layers.

Generation of induced pluripotent stem cells (iPSC) from an atrial fibrillation patient carrying a KCNA5 p.D322H mutation.

Atrial fibrillation (AF) is the most common sustained arrhythmia associated with several cardiac risk factors, but increasing evidences indicated a genetic component. Indeed, genetic variations of the atrial specific KCNA5 gene have been identified in patients with early-onset lone AF. To investigate the molecular mechanisms underlying AF, we reprogrammed to pluripotency polymorphonucleated leukocytes isolated from the blood of a patient carrying a KCNA5 p.D322H mutation, using a commercially available non-integrating system. The generated iPSCs expressed pluripotency markers and differentiated toward cells belonging to the three embryonic germ layers. Moreover, the cells showed a normal karyotype and retained the p.D322H mutation.

De novo 1Mb interstitial deletion of 8p22 in a patient with slight mental retardation and speech delay.

We report on a nine years old girl born after 41 weeks of normal gestation with psychomotor retardation, speech delay and minimal dysmorphic signs: antimongolic cut eyes, small mouth, short philtrum and hypertelorism. The use of the high-resolution Affymetrix Human Mapping GeneChip 250 K NspI array allowed the characterization of a de novo 1Mb deletion on the short arm (p22) of a chromosome 8. Molecular cytogenetic-FISH with BAC probes (RP11) confirmed the deletion. The deleted region includes part of the sarcoglycan zeta (SGCZ) gene, involved in the sarcoglycan complex formation, and the microRNA 383. The deletion described in our patient falls 319 Kb upstream of the Tumor Suppressor Candidate 3 (TUSC3) gene. In this chromosomal region, a limited number of cases of overlapping deletions, of variable extensions and characterized by heterogeneous clinical phenotype, have been reported. The deleted region described in our patient is the smallest among those so far described in this region.