Agr2‐interacting Prod1‐like protein Tfp4 from Xenopus laevis is necessary for early forebrain and eye development as well as for the tadpole appendage regeneration

The Agr family genes, Ag1, Agr2, and Agr3, encode for the thioredoxin domain containing secreted proteins and are specific only for vertebrates. These proteins are attracting increasing attention due to their involvement in many physiological and pathological processes, including exocrine secretion, cancer, regeneration of the body appendages, and the early brain development. At the same time, the mode by which Agrs regulate intracellular processes are poorly understood. Despite that the receptor to Agr2, the membrane anchored protein Prod1, has been firstly discovered in Urodeles, and it has been shown to interact with Agr2 in the regenerating limb, no functional homologs of Prod1 were identified in other vertebrates. This raises the question of the mechanisms by which Agrs can regulate regeneration in other lower vertebrates. Recently, we have identified that Tfp4 (three‐fingers Protein 4), the structural and functional homolog of Prod1 in Anurans, interacts with Agr2 in Xenopus laevis embryos. In the present work we show by several methods that the activity of Tfp4 is essential for the tadpole tail regeneration as well as for the early eye and forebrain development during embryogenesis. These data show for the first time the common molecular mechanism of regeneration regulation in amphibians by interaction of Prod1 and Agr2 proteins.     

Synthesis and SAR of 4-aminocyclopentapyrrolidines as orally active N-type calcium channel inhibitors for inflammatory and neuropathic pain

A novel series of N-type calcium channel inhibitors have been discovered. Optimization of potency and HT-ADME properties provides 4-aminocyclopentapyrrolidines with analgesic efficacy after oral dosing.     

Type III CRISPR-Cas Systems: Deciphering the Most Complex Prokaryotic Immune System

Biochemistry (Moscow) - The emergence and persistence of selfish genetic elements is an intrinsic feature of all living systems. Cellular organisms have evolved a plethora of elaborate defense...     

Characterization of purinergic receptor expression in ARPKD cystic epithelia

Polycystic kidney diseases (PKDs) are a group of inherited nephropathies marked by formation of fluid-filled cysts along the nephron. Growing evidence suggests that in the kidney formation of cysts and alteration of cystic electrolyte transport are associated with purinergic signaling. PCK/CrljCrl-Pkhd1pck/CRL (PCK) rat, an established model of autosomal recessive polycystic kidney disease (ARPKD), was used here to test this hypothesis. Cystic fluid of PCK rats and their cortical tissues exhibited significantly higher levels of ATP compared to Sprague Dawley rat kidney cortical interstitium as assessed by highly sensitive ATP enzymatic biosensors. Confocal calcium imaging of the freshly isolated cystic monolayers revealed a stronger response to ATP in a higher range of concentrations (above 100 μM). The removal of extracellular calcium results in the profound reduction of the ATP evoked transient, which suggests calcium entry into the cyst-lining cells is occurring via the extracellular (ionotropic) P2X channels. Further use of pharmacological agents (α,β-methylene-ATP, 5-BDBD, NF449, isoPPADS, AZ10606120) and immunofluorescent labeling of isolated cystic epithelia allowed us to narrow down potential candidate receptors. In conclusion, our ex vivo study provides direct evidence that the profile of P2 receptors is shifted in ARPKD cystic epithelia in an age-related manner towards prevalence of P2X₄ and/or P2X₇ receptors, which opens new avenues for the treatment of this disease.     

Evolutionary history of the genus Sorex (Soricidae,Eulipotyphla) as inferred from multigene data

The genus Sorex is one of the most diverse and ecologically successful lineages of the family Soricidae. We present the first multilocus nuclear phylogeny focusing on the nominal subgenus Sorex s.str., which is distributed mainly in the northern Palearctic. The nuclear tree (six exons) provides more resolution than the mitochondrial data (cytb) and supports subdivision into eight species groups within Sorex s.str., most of which correspond to those recognized from chromosome data. The European species S. alpinus is consistently placed as the basal lineage in the Palearctic clade, while the next split separates the east‐Tibetan group of striped shrews (S. aff. cylindricauda, S. bedfordiae, S. excelsus). Within the remaining species, the following well‐supported clades are identified at the supra‐group level: “araneus” species group+S. samniticus; the “caecutiens” group+the “minutus” group, the latter also including S. minutissimus, S. gracillimus and S. thibetanus. S. raddei and S. roboratus represent separate lineages with no close relatives. The fossil‐calibrated molecular clock placed the divergence between Sorex s.str. and Otisorex at the Early/Middle Miocene boundary. Basal radiation of the crown Sorex s.str. was estimated to have occurred in the middle of the Late Miocene. A more than threefold increase in the diversification rate is inferred for the Early Pliocene. Taxonomic implications including potential genus ranks for Sorex s.str. and Otisorex are discussed. S. alpinus is placed in the monotypic subgenus Homalurus. The full species status of S. buchariensis and S. thibetanus and close relationships between S. cf. cansulus and S. caecutiens are confirmed.     

Enhanced-contrast two-photon optogenetic pH sensing and pH-resolved brain imaging

We present experiments on cell cultures and brain slices that demonstrate two-photon optogenetic pH sensing and pH-resolved brain imaging using a laser driver whose spectrum is carefully tailored to provide the maximum contrast of a ratiometric two-photon fluorescence readout from a high-brightness genetically encoded yellow-fluorescent-protein-based sensor, SypHer3s. Two spectrally isolated components of this laser field are set to induce two-photon-excited fluorescence (2PEF) by driving SypHer3s through one of two excitation pathways—via either the protonated or deprotonated states of its chromophore. With the spectrum of the laser field accurately adjusted for a maximum contrast of these two 2PEF signals, the ratio of their intensities is shown to provide a remarkably broad dynamic range for pH measurements, enabling high-contrast optogenetic deep-brain pH sensing and pH-resolved 2PEF imaging within a vast class of biological systems, ranging from cell cultures to the living brain.