In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

The combination of a tumor-penetrating peptide (TPP) with a peptide able to interfere witha given protein–protein interaction (IP) is a promising strategy with potential clinical application.Little is known about the impact of fusing a TPP with an IP, both in terms of internalization andfunctional effect. Here, we analyze these aspects in the context of breast cancer, targeting PP2A/SET interaction, using both in silico and in vivo approaches. Our results support the fact that state-of-theart deep learning approaches developed for protein–peptide interaction modeling can reliably identify good candidate poses for the IP-TPP in interaction with the Neuropilin-1 receptor. The association of the IP with the TPP does not seem to affect the ability of the TPP to bind to Neuropilin-1. Molecular simulation results suggest that peptide IP-GG-LinTT1 in a cleaved form interacts with Neuropilin-1 in a more stable manner and has a more helical secondary structure than the cleaved IP-GG-iRGD.Surprisingly, in silico investigations also suggest that the non-cleaved TPPs can bind the Neuropilin-1 in a stable manner. The in vivo results using xenografts models show that both bifunctional peptides resulting from the combination of the IP and either LinTT1 or iRGD are effective against tumoral growth. The peptide iRGD-IP shows the highest stability to serum proteases degradation while having the same antitumoral effect as Lin TT1-IP, which is more sensitive to proteases degradation.Our results support the development of the TPP-IP strategy as therapeutic peptides against cancerFacultad de Ciencias Médica

Aménagement d’ossuaires dans le baptistère paléochrétien de Brioude (Haute-Loire) : sélection, tri des ossements et relation À l’Âge au décès

Le baptistère de Brioude constitue actuellement un ensemble unique en Auvergne. Intégré au sanctuaire de Saint-Julien au début du haut Moyen âge, il présente des sépultures installées intra muros au moment de son fonctionnement, fait exceptionnel en Gaule mérovingienne. La datation particulièrement bien établie de l’ensemble des vestiges et, par conséquent, du rythme des changements qu’ils ont subis, a permis d’identifier deux phases funéraires : la première, datée du VIe s. ap. J.-C., est contemporaine de l’utilisation du baptistère. La seconde, désigne l’ensemble des sépultures installées dans le niveau de démolition du baptistère sur les tombes précédentes ; elles sont associées à un nouvel édifice élevé sur l’emprise du baptistère au début du VIIe s. L’analyse du fonctionnement de l’ensemble de cet espace funéraire a permis d’identifier une étape charnière entre ces deux principales phases chronologiques. Celle-ci correspond au réaménagement de plusieurs sépultures appartenant à la première phase, en raison de la construction de l’édifice funéraire remplaçant le baptistère. Ces perturbations ont entraîné le déplacement ou la destruction partielle de certains sarcophages. Une partie des ossements ainsi exhumés a été rassemblée en ossuaires. Trois ossuaires ont été mis au jour dans une fosse creusée dans le sol de la salle baptismale. La présence de liaisons ostéologiques de deuxième ordre entre ces différents ensembles démontre, d’une part, que leur mise en place résulte d’un processus unique, d’autre part, que la distribution de l’ensemble des vestiges osseux n’a pas été aléatoire. En effet, une sélection et un tri d’os matures en fonction de leur catégorie (os longs, blocs cranio-faciaux et os de petite et moyenne tailles) ont été réalisés et répartis en trois dépôts distincts. Nous constatons en outre, que les os pairs non matures ont été répartis dans deux ossuaires. Enfin, l’estimation de l’âge de ces jeunes sujets les place majoritairement parmi la classe des 5-9 ans, individus d’ailleurs absents du reste de l’espace sépulcral. Ces résultats laissent envisager l’existence d’une zone originelle réservée à cette classe d’âge au décès de la population, détruite lors de la construction du bâtiment de la seconde phase.The baptistery of Brioude is today a unique monument in Auvergne. It was associated with the sanctuary housing the relics of Saint Julien, which dates to the early Middle Ages. During its period of use, the baptistery provided for intra muros burial. This is a unique occurrence in Merovingian Gaul. Two phases of funerary use could be identified from the regularity with which the remains had been treated. The first, dating from the 6th century AD, is contemporary with the use of the baptistery. The second dates from the middle of Merovingian period (from the 7th century A.D.) and is associated with the building of a new structure on the site of the baptistery. This structure was accompanied by burials placed directly over those of the previous phase. The analysis of spatial relationships among burials enabled us to identify a transitional stage between these two phases. This stage was identified on the basis of the disturbance of several burials belonging to the first phase, subsequent to the construction of the structure of the second phase. These disturbances led to the displacement of partial destruction of some sarcophagi and the inclusion of some disturbed skeletal remains in ossuaries. Three ossuaries have been discovered under the floor of the baptistery. The identification of osteological relations of the second order among these different groups demonstrates that, first, the three ossuaries resulted from a single action and, second, the distribution of skeletal elements was not random but that selection and sorting of adult bones had been carried out according to their anatomical type (long bones, cranium, small and middle-sized bones), and these had been separated into three different deposits. Furthermore, we noted that paired immature skeletal elements were divided between two ossuaries. Finally, the age assessment of these young individuals classified them into the 5-9 age category, a group that was absent from the rest of the burial area. These results lead us to hypothesize that there had once been a burial area reserved for this part of the population. This area seems to have been destroyed during the construction of the second phase structure

In Silico and In Vivo Studies of a Tumor-Penetrating and Interfering Peptide with Antitumoral Effect on Xenograft Models of Breast Cancer

The combination of a tumor-penetrating peptide (TPP) with a peptide able to interfere witha given protein–protein interaction (IP) is a promising strategy with potential clinical application.Little is known about the impact of fusing a TPP with an IP, both in terms of internalization andfunctional effect. Here, we analyze these aspects in the context of breast cancer, targeting PP2A/SET interaction, using both in silico and in vivo approaches. Our results support the fact that state-of-theart deep learning approaches developed for protein–peptide interaction modeling can reliably identify good candidate poses for the IP-TPP in interaction with the Neuropilin-1 receptor. The association of the IP with the TPP does not seem to affect the ability of the TPP to bind to Neuropilin-1. Molecular simulation results suggest that peptide IP-GG-LinTT1 in a cleaved form interacts with Neuropilin-1 in a more stable manner and has a more helical secondary structure than the cleaved IP-GG-iRGD.Surprisingly, in silico investigations also suggest that the non-cleaved TPPs can bind the Neuropilin-1 in a stable manner. The in vivo results using xenografts models show that both bifunctional peptides resulting from the combination of the IP and either LinTT1 or iRGD are effective against tumoral growth. The peptide iRGD-IP shows the highest stability to serum proteases degradation while having the same antitumoral effect as Lin TT1-IP, which is more sensitive to proteases degradation.Our results support the development of the TPP-IP strategy as therapeutic peptides against cancerFacultad de Ciencias Médica

New evidence of a mitochondrial genetic background paradox: Impact of the J haplogroup on the A3243G mutation

International audienceBackground: The A3243G mutation in the tRNALeu gene (UUR), is one of the most common pathogenic mitochondrial DNA (mtDNA) mutations in France, and is associated with highly variable and heterogeneous disease phenotypes. To define the relationships between the A3243G mutation and mtDNA backgrounds, we determined the haplogroup affiliation of 142 unrelated French patients – diagnosed as carriers of the A3243G mutation – by control-region sequencing and RFLP survey of their mtDNAs. Results: The analysis revealed 111 different haplotypes encompassing all European haplogroups, indicating that the 3243 site might be a mutational hot spot. However, contrary to previous findings, we observed a statistically significant underepresentation of the A3243G mutation on haplogroup J in patients (p = 0.01, OR = 0.26, C.I. 95%: 0.08–0.83), suggesting that might be due to a strong negative selection at the embryo or germ line stages. Conclusion: Thus, our study supports the existence of mutational hotspot on mtDNA and a "haplogroup J paradox," a haplogroup that may increase the expression of mtDNA pathogenic mutations, but also be beneficial in certain environmental contexts

TSPO: kaleidoscopic 18-kDa amid biochemical pharmacology, control and targeting of mitochondria

The 18-kDa translocator protein (TSPO) localizes in the outer mitochondrial membrane (OMM) of cells and is readily up-regulated under various pathological conditions such as cancer, inflammation, mechanical lesions and neurological diseases. Able to bind with high affinity synthetic and endogenous ligands, its core biochemical function resides in the translocation of cholesterol into the mitochondria influencing the subsequent steps of (neuro-)steroid synthesis and systemic endocrine regulation. Over the years, however, TSPO has also been linked to core cellular processes such as apoptosis and autophagy. It interacts and forms complexes with other mitochondrial proteins such as the voltage-dependent anion channel (VDAC) via which signalling and regulatory transduction of these core cellular events may be influenced. Despite nearly 40 years of study, the precise functional role of TSPO beyond cholesterol trafficking remains elusive even though the recent breakthroughs on its high-resolution crystal structure and contribution to quality-control signalling of mitochondria. All this along with a captivating pharmacological profile provides novel opportunities to investigate and understand the significance of this highly conserved protein as well as contribute the development of specific therapeutics as presented and discussed in the present review

Why dig looted tombs? Two examples and some answers from Keushu (Ancash highlands, Peru)

Looted tombs at Andean archaeological sites are largely the result of a long tradition of trade in archaeological artefacts coupled with the 17th century policy of eradicating ancestor veneration and destroying mortuary evidence in a bid to “extirpate idolatry”. On the surface, looted funerary contexts often present abundant disarticulated and displaced human remains as well as an apparent absence of mortuary accoutrements. What kind of information can archaeologists and biological anthropologists hope to gather from such contexts? In order to gauge the methodological possibilities and interpretative limitations of targeting looted tombs, we fully excavated two collective funerary contexts at the archaeological site of Keushu (district and province of Yungay, Ancash, Peru; c. 2000 B.C.-A.D. 1600), which includes several dozen tombs, many built under large boulders or rock shelters, all of which appear disturbed by looting. The first is located in the ceremonial sector and excavation yielded information on four individuals; the second, in the funerary and residential sector, held the remains of seventy individuals - adults and juveniles. Here, we present and discuss the recovered data and suggest that careful, joint excavations by archaeologists and biological anthropologists can retrieve evidence of past mortuary practices, aid the biological characterisation of mortuary populations and help distinguish between a broad range of looting practices and post-depositional processes

Does natural selection explain the fine scale genetic structure at the nuclear exon Glu-5 ' in blue mussels from Kerguelen ?

The Kerguelen archipelago, isolated in the Southern Ocean, shelters a blue mussel Mytilus metapopulation far from any influence of continental populations or any known hybrid zone. The finely carved coast leads to a highly heterogeneous habitat. We investigated the impact of the environment on the genetic structure in those Kerguelen blue mussels by relating allele frequencies to habitat descriptors. A total sample comprising up to 2248 individuals from 35 locations was characterized using two nuclear markers, mac-1 and Glu-5, and a mitochondrial marker (COI). The frequency data from 9 allozyme loci in 9 of these locations were also reanalyzed. Two other nuclear markers (EFbis and EFprem's) were monomorphic. Compared to Northern Hemisphere populations, polymorphism in Kerguelen blue mussels was lower for all markers except for the exon Glu-5. At Glu-5, genetic differences were observed between samples from distinct regions (F-CT=0.077), as well as within two regions, including between samples separated by <500m. No significant differentiation was observed in the AMOVA analyses at the two other markers (mac-1 and COI). Like mac-1, all allozyme loci genotyped in a previous publication, displayed lower differentiation (Jost's D) and F-ST values than Glu-5. Power simulations and confidence intervals support that Glu-5 displays significantly higher differentiation than the other loci (except a single allozyme for which confidence intervals overlap). AMOVA analyses revealed significant effects of the giant kelp Macrocystis and wave exposure on this marker. We discuss the influence of hydrological conditions on the genetic differentiation among regions. In marine organisms with high fecundity and high dispersal potential, gene flow tends to erase differentiation, but this study showed significant differentiation at very small distance. This may be explained by the particular hydrology and the carved coastline of the Kerguelen archipelago, together with spatially variable selection at Glu-5

OPA1-related dominant optic atrophy is not strongly influenced by mitochondrial DNA background

<p>Abstract</p> <p>Background</p> <p>Leber's hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA) are the most frequent forms of hereditary optic neuropathies. LHON is associated with mitochondrial DNA (mtDNA) mutations whereas ADOA is mainly due to mutations in the OPA1 gene that encodes a mitochondrial protein involved in the mitochondrial inner membrane remodeling. A striking influence of mtDNA haplogroup J on LHON expression has been demonstrated and it has been recently suggested that this haplogroup could also influence ADOA expression. In this study, we have tested the influence of mtDNA backgrounds on OPA1 mutations.</p> <p>Methods</p> <p>To define the relationships between OPA1 mutations and mtDNA backgrounds, we determined the haplogroup affiliation of 41 French patients affected by OPA1-related ADOA by control-region sequencing and RFLP survey of their mtDNAs.</p> <p>Results</p> <p>The comparison between patient and reference populations did not revealed any significant difference.</p> <p>Conclusion</p> <p>Our results argue against a strong influence of mtDNA background on ADOA expression. These data allow to conclude that OPA1 could be considered as a "severe mutation", directly responsible of the optic atrophy, whereas OPA1-negative ADOA and LHON mutations need an external factor(s) to express the pathology (i.e. synergistic interaction with mitochondrial background).</p

Molecular modeling of a tandem two pore domain potassium channel reveals a putative binding Site for general anesthetics

[Image: see text] Anesthetics are thought to mediate a portion of their activity via binding to and modulation of potassium channels. In particular, tandem pore potassium channels (K2P) are transmembrane ion channels whose current is modulated by the presence of general anesthetics and whose genetic absence has been shown to confer a level of anesthetic resistance. While the exact molecular structure of all K2P forms remains unknown, significant progress has been made toward understanding their structure and interactions with anesthetics via the methods of molecular modeling, coupled with the recently released higher resolution structures of homologous potassium channels to act as templates. Such models reveal the convergence of amino acid regions that are known to modulate anesthetic activity onto a common three- dimensional cavity that forms a putative anesthetic binding site. The model successfully predicts additional important residues that are also involved in the putative binding site as validated by the results of suggested experimental mutations. Such a model can now be used to further predict other amino acid residues that may be intimately involved in the target-based structure–activity relationships that are necessary for anesthetic binding

Mutation Rate Switch inside Eurasian Mitochondrial Haplogroups: Impact of Selection and Consequences for Dating Settlement in Europe

R-lineage mitochondrial DNA represents over 90% of the European population and is significantly present all around the planet (North Africa, Asia, Oceania, and America). This lineage played a major role in migration “out of Africa” and colonization in Europe. In order to determine an accurate dating of the R lineage and its sublineages, we analyzed 1173 individuals and complete mtDNA sequences from Mitomap. This analysis revealed a new coalescence age for R at 54.500 years, as well as several limitations of standard dating methods, likely to lead to false interpretations. These findings highlight the association of a striking under-accumulation of synonymous mutations, an over-accumulation of non-synonymous mutations, and the phenotypic effect on haplogroup J. Consequently, haplogroup J is apparently not a Neolithic group but an older haplogroup (Paleolithic) that was subjected to an underestimated selective force. These findings also indicated an under-accumulation of synonymous and non-synonymous mutations localized on coding and non-coding (HVS1) sequences for haplogroup R0, which contains the major haplogroups H and V. These new dates are likely to impact the present colonization model for Europe and confirm the late glacial resettlement scenario