👤 Dietmar Weichert

Class B1 G protein-coupled receptors (GPCRs) are peptide hormone receptors and well validated therapeutic targets, however development of non-peptide drugs targeting this class of receptors is challenging. Recently, a series of isoquinoline-based derivates were reported in the patent literature as allosteric ligands for the glucagon receptor subfamily, and two compounds, LSN3451217 and LSN3556672, were used to facilitate structural studies with the glucagon-like peptide-1 receptor (GLP-1R) and glucose dependent insulinotropic peptide receptor (GIPR) bound to orthosteric agonists. Here we pharmacologically characterized stereoisomers of LSN3451217 and LSN3556672, across the class B1 GPCR family. This revealed LSN3556672 isomers are agonists for the glucagon receptor (GCGR), GLP-1R, GIPR and the calcitonin receptor (CTR), albeit the degree of agonism varied at each receptor. In contrast, LSN3451217 isomers were more selective agonists at the GLP-1R, with lower potency at the GCGR and CTR and no activity at the GIPR. All compounds also modulated peptide-mediated cyclic adenosine monophosphate (cAMP) signaling at the GIPR, and to a lesser extent the GLP-1R, in a probe-dependent manner, with modest positive allosteric modulation observed for some peptides, and negligible effects observed with other peptides. In contrast neutral or weak negative/positive allosteric modulation was observed with peptides assessed at the GCGR and CTR. This study expands our knowledge on class B1 GPCR allosteric modulation and may have implications for future structural and drug discovery efforts targeting the class B1 GPCR subfamily. Show less

To elaborate the antenatal sonographic findings of fetuses with the suspicion of fetal akinesia, thereby focusing on the accuracy of prenatal differentiation between subtypes of fetal akinesia, namely Pena-Shokeir phenotype (PSP) and arthrogryposis multiplex congenita (AMC). We herein present our experience of 21 patients with PSP and AMC diagnosed antenatally at a tertiary prenatal referral center. During the study period 30,485 consecutive high- and low-risk pregnancies were examined. The prenatal sonograms, pediatric charts and autopsy data of affected individuals were reviewed. Our findings were analyzed together with findings retrieved from the literature. The diagnosis of AMC has been established between 12+0 and 30+1 gestational weeks, whereas cases found to have PSP were all diagnosed in advanced pregnancy. In accordance to previous findings, our data suggest that pulmonary hypoplasia is obligatory in PSP and cannot be found in AMC. Therefore, all pregnancies (9/9) affected by PSP were terminated on parental request. Of those fetuses with AMC, 3/12 were liveborn, 2 of which have neuromotoric disabilities. Establishing the correct prenatal diagnosis of PSP and AMC at an early stage and its diligent prognostic evaluation play a crucial role in order to provide adequate advice to the afflicted parents and to enable appropriate intervention at an early stage. Show less