Telomere elongation and clinical response to androgen treatment in a patient with aplastic anemia and a heterozygous hTERT gene mutation

Telomere length (TL) both reflects and limits the replicative life span of normal somatic cells. As a consequence, critically shortened telomeres are associated with a variety of disease states. Telomere attrition can be counteracted by a nucleoprotein complex containing telomerase. Mutations in subunits of telomerase, telomerase-binding proteins as well as in members of the shelterin complex have been described both in inherited and acquired bone marrow failure syndromes. Here, we report on a patient with acquired aplastic anemia and a nonsynonymous variation of codon 1062 of the hTERT gene (p.Ala1062Thr) whose substantial and maintained hematologic response to long-term androgen treatment (including complete transfusion independence) was paralleled by a significant and continued increase in TL in multilineage peripheral blood cells. To our knowledge, this represents the first case of sustained telomere elongation in hematopoietic stem cells induced by a pharmacological approach in vivo (141 words).     

Detection of free fatty acid receptor 1 expression: the critical role of negative and positive controls

Aims/hypothesis

Adequate evaluation of protein expression is a crucial prerequisite for functional studies. Commonly used strategies comprise detection of proteins by specific antibodies using western blotting and immunohistochemical staining, or detection of mRNA by in situ hybridisation and RT-PCR. We evaluated the tools for the detection of free fatty acid receptor 1 (FFAR1) expression.

Methods

Commercially available antibody preparations were used to detect endogenous expression of the FFAR1 receptor and this was compared with cell preparations deficient or overexpressing the mouse or human receptor. Concentrations of mRNA were evaluated by RT-PCR.

Results

All insulin-secreting cells, INS-1E, Min6 and mouse islets showed specific expression of Ffar1 at the mRNA level. However, none of the commercially available antibodies specifically detected rat, mouse or human FFAR1.

Conclusions/interpretation

Proper positive and negative controls are an important prerequisite for the evaluation of FFAR1 expression.     

Reduced thymic expression of ErbB receptors without auto-antibodies against synaptic ErbB in myasthenia gravis

In myasthenia gravis (MG), the neuromuscular transmission is impaired mainly by auto-antibodies against the acetylcholine receptor (AChR) or MuSK. In about 5% of the MG patients, however, the auto-antigen is still unknown. We investigated whether these idiopathic MG patients (iMG) have auto-antibodies against ErbB proteins, which influence the AChR density at the NMJ. Our results show reduced mRNA expression levels of ErbB4 in thymus tissue of iMG patients compared to AChR-MG and non-MG patients, but we could not detect anti-ErbB antibodies in sera of iMG patients. Therefore, our results do not support a role for ErbB receptors as auto-antigens in iMG patients.     

Modulation of keratinocyte growth factor (KGF) mRNA expression in human dermal fibroblasts grown in monolayer or within a collagen matrix

Abstract In this study, we analysed the modulation of keratinocyte growth factor (KGF) mRNA expression in human dermal fibroblasts cultured either in monolayer or within a collagen matrix (dermal equivalent). In monolayer cultures, KGF expression by quiescent fibroblasts was stimulated by different growth substances such as serum, epidermal growth factor and basic fibroblast growth factor. Moreover, we demonstrated that the induction of this gene was mediated by at least 2 different signalling pathways involving protein kinase C (PKC) and cAMP. In dermal equivalents, we observed that the collagen matrix negatively modulated KGF mRNA expression. Indeed, among the growth substances used, only the serum slightly stimulated KGF expression. Nevertheless, as in monolayers, this induction involved at least PKC and cAMP signalling pathways. As the collagen matrix can modulate fibroblast growth, we also studied KGF expression in growing fibroblasts from either monolayer cultures or dermal equivalents. We then showed that this collagen matrix negatively influenced KGF expression independently of the proliferative state of fibroblasts. All these results underline the fact that KGF mRNA expression by human dermal fibroblasts is induced by different substances; however this expression can be modulated by fibroblast-matrix interactions.