V3 stain-free workflow for a practical, convenient, and reliable total protein loading control in western blotting

Comparative proteomic analysis of the ovarian fluid and eggs of Siberian sturgeon

BACKGROUND

Sturgeon species are living fossils that exhibit unique reproductive characteristics, and elucidation of the molecular processes governing the formation and quality of sturgeon eggs is crucial. However, comprehensive data on the protein composition of sturgeon ovarian fluid (OF) and eggs and their functional significance are lacking. To address this knowledge gap, the aim of the present study was to conduct a comprehensive comparative proteomic analysis of Siberian sturgeon OF and eggs using liquid chromatography-mass spectrometry (LC-MS/MS).

RESULTS

A total of 617 proteins were identified in OF, and 565 proteins were identified in eggs. A total of 772 proteins showed differential abundance. Among the differentially abundant proteins, 365 were more abundant in OFs, while 407 were more abundant in eggs. We identified 339 proteins unique to OFs and 287 proteins specific to eggs, and further investigated the top 10 most abundant proteins in each. The functional annotation of the OF proteins highlighted their predominant association with immune system processes, including the complement and coagulation cascade, neutrophil and leukocyte-mediated immunity, cholesterol metabolism, and regulation of the actin cytoskeleton. Analysis of egg proteins revealed enrichment in metabolic pathways, such as oxidative phosphorylation and fatty acid metabolism, and protein ubiquitination and translation. OF-specific proteins included extracellular matrix and secretory vesicles, and eggs were enriched in proteins localized to mitochondria and ribosome components.

CONCLUSIONS

This study presents the first comprehensive characterization of the protein composition of sturgeon OF and eggs and elucidates their distinct functional roles. These findings advance our understanding of sturgeon reproduction, OF-egg signaling and the origin of OF proteins. The mass spectrometry proteomics data have been deposited in the ProteomeXchange Consortium with the dataset identifier PXD044168 to ensure accessibility for further research.

Liquid semen storage-induced alteration in the protein composition of turkey (Meleagris gallopavo) spermatozoa

Liquid storage of turkey semen without the loss of fertilizing ability is of practical interest to the poultry industry. However, fertility rates from liquid-stored turkey semen decline within a few hours. A clear cause of the decline in spermatozoa quality remains unidentified. Therefore, the purpose of the present study was to monitor the dynamics of proteomic changes in spermatozoa during 48 h of liquid storage by 2-dimensional difference in-gel electrophoresis coupled with matrix-assisted laser desorption/ionization mass spectrometry. A total of 57 protein spots were differentially expressed between fresh and stored spermatozoa; 42 spots were more and 15 were less abundant after 48 h of semen storage. Raw proteomic data are available via ProteomeXchange with identifier PXD043050. The selected differentially expressed proteins (DEPs) were validated by western blotting and localized in specific spermatozoa structures by immunofluorescence, such as the head (acrosin and tubulin α), midpiece (acrosin, aconitate hydratase 2, and glycerol-3-phosphate dehydrogenase) and tail (tubulin α). Most of the DEPs that changed in response to liquid storage were related to flagellum-dependent cell motility, energy derivation through oxidation of organic compounds and induction of fertilization, suggesting the complexity of the processes leading to the decrease in stored semen quality. The damaging effect of liquid storage on spermatozoa flagellum manifested as more microtubule proteins, such as tubulins and tektins, most likely formed by posttranslational modifications, tubulin α relocation from the tail to the sperm head, which appeared after 48 h of semen storage, and decreases in fibrous shelf proteins at the same time. Motility could be affected by dysregulation of Ca2+-binding proteins and disturbances in energy metabolism in spermatozoa flagellum. Regarding sperm mitochondria, DEPs involved in energy derivation through the oxidation of organic compounds indicated disturbances in fatty acid beta oxidation and the tricarboxylic acid cycle as possible reasons for energy deficiency during liquid storage. Disturbances in acrosin and 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase zeta may be involved in rapid declines in the fertility potential of stored turkey spermatozoa. These results showed the complexity of the processes leading to a decrease in stored semen quality and broadened knowledge of the detrimental effects of liquid storage on turkey spermatozoa physiology.

Elucidation of the low-expressing erythroid CR1 phenotype by bioinformatic mining of the GATA1-driven blood-group regulome

Genetic determinants underlying most human blood groups are now clarified but variation in expression levels remains largely unexplored. By developing a bioinformatics pipeline analyzing GATA1/Chromatin immunoprecipitation followed by sequencing (ChIP-seq) datasets, we identify 193 potential regulatory sites in 33 blood-group genes. As proof-of-concept, we aimed to delineate the low-expressing complement receptor 1 (CR1) Helgeson phenotype on erythrocytes, which is correlated with several diseases and protects against severe malaria. We demonstrate that two candidate CR1 enhancer motifs in intron 4 bind GATA1 and drive transcription. Both are functionally abolished by naturally-occurring SNVs. Erythrocyte CR1-mRNA and CR1 levels correlate dose-dependently with genotype of one SNV (rs11117991) in two healthy donor cohorts. Haplotype analysis of rs11117991 with previously proposed markers for Helgeson shows high linkage disequilibrium in Europeans but explains the poor prediction reported for Africans. These data resolve the longstanding debate on the genetic basis of inherited low CR1 and form a systematic starting point to investigate the blood group regulome.

NHR-23 activity is necessary for C. elegans developmental progression and apical extracellular matrix structure and function

Nematode molting is a remarkable process where animals must repeatedly build a new apical extracellular matrix (aECM) beneath a previously built aECM that is subsequently shed. The nuclear hormone receptor NHR-23 (also known as NR1F1) is an important regulator of C. elegans molting. NHR-23 expression oscillates in the epidermal epithelium, and soma-specific NHR-23 depletion causes severe developmental delay and death. Tissue-specific RNAi suggests that nhr-23 acts primarily in seam and hypodermal cells. NHR-23 coordinates the expression of factors involved in molting, lipid transport/metabolism and remodeling of the aECM. NHR-23 depletion causes dampened expression of a nas-37 promoter reporter and a loss of reporter oscillation. The cuticle collagen ROL-6 and zona pellucida protein NOAH-1 display aberrant annular localization and severe disorganization over the seam cells after NHR-23 depletion, while the expression of the adult-specific cuticle collagen BLI-1 is diminished and frequently found in patches. Consistent with these localization defects, the cuticle barrier is severely compromised when NHR-23 is depleted. Together, this work provides insight into how NHR-23 acts in the seam and hypodermal cells to coordinate aECM regeneration during development.

Podocyte Geranylgeranyl Transferase Type-I Is Essential for Maintenance of the Glomerular Filtration Barrier

SIGNIFICANCE STATEMENT

A tightly regulated actin cytoskeleton attained through balanced activity of RhoGTPases is crucial to maintaining podocyte function. However, how RhoGTPases are regulated by geranylgeranylation, a post-translational modification, has been unexplored. The authors found that loss of the geranylgeranylation enzyme geranylgeranyl transferase type-I (GGTase-I) in podocytes led to progressive albuminuria and foot process effacement in podocyte-specific GGTase-I knockout mice. In cultured podocytes, the absence of geranylgeranylation resulted in altered activity of its downstream substrates Rac1, RhoA, Cdc42, and Rap1, leading to alterations of β1-integrins and actin cytoskeleton structural changes. These findings highlight the importance of geranylgeranylation in the dynamic management of RhoGTPases and Rap1 to control podocyte function, providing new knowledge about podocyte biology and glomerular filtration barrier function.

BACKGROUND

Impairment of the glomerular filtration barrier is in part attributed to podocyte foot process effacement (FPE), entailing disruption of the actin cytoskeleton and the slit diaphragm. Maintenance of the actin cytoskeleton, which contains a complex signaling network through its connections to slit diaphragm and focal adhesion proteins, is thus considered crucial to preserving podocyte structure and function. A dynamic yet tightly regulated cytoskeleton is attained through balanced activity of RhoGTPases. Most RhoGTPases are post-translationally modified by the enzyme geranylgeranyl transferase type-I (GGTase-I). Although geranylgeranylation has been shown to regulate activities of RhoGTPases and RasGTPase Rap1, its significance in podocytes is unknown.

METHODS

We used immunofluorescence to localize GGTase-I, which was expressed mainly by podocytes in the glomeruli. To define geranylgeranylation's role in podocytes, we generated podocyte-specific GGTase-I knockout mice. We used transmission electron microscopy to evaluate FPE and measurements of urinary albumin excretion to analyze filtration barrier function. Geranylgeranylation's effects on RhoGTPases and Rap1 function were studied in vitro by knockdown or inhibition of GGTase-I. We used immunocytochemistry to study structural modifications of the actin cytoskeleton and β1 integrins.

RESULTS

Depletion of GGTase-I in podocytes in vivo resulted in FPE and concomitant early-onset progressive albuminuria. A reduction of GGTase-I activity in cultured podocytes disrupted RhoGTPase balance by markedly increasing activity of RhoA, Rac1, and Cdc42 together with Rap1, resulting in dysregulation of the actin cytoskeleton and altered distribution of β1 integrins.

CONCLUSIONS

These findings indicate that geranylgeranylation is of crucial importance for the maintenance of the delicate equilibrium of RhoGTPases and Rap1 in podocytes and consequently for the maintenance of glomerular integrity and function.

STEAP1 regulation and its influence modulating the response of LNCaP prostate cancer cells to bicalutamide, enzalutamide and apalutamide

Anti‑androgen drugs are the standard pharmacological therapies for treatment of non‑metastatic prostate cancer (PCa). However, the response of PCa cells may depend on the anti‑androgen used and often patients become resistant to treatment. Thus, studying how the anti‑androgen drugs affect oncogenes expression and action and the identification of the best strategy for combined therapies are essential to improve the efficacy of treatments. The Six Transmembrane Epithelial Antigen of the Prostate 1 (STEAP1) is an oncogene associated with PCa progression and aggressiveness, although its relationship with the androgen receptor signaling remains to be elucidated. The present study aimed to evaluate the effect of anti‑androgens in regulating STEAP1 expression and investigate whether silencing STEAP1 can make PCa cells more sensitive to anti‑androgen drugs. For this purpose, wild‑type and STEAP1 knockdown LNCaP cells were exposed to bicalutamide, enzalutamide and apalutamide. Bicalutamide decreased the expression of STEAP1, but enzalutamide and apalutamide increased its expression. However, decreased cell proliferation and increased apoptosis was observed in response to all drugs. Overall, the cellular and molecular effects were similar between LNCaP wild‑type and LNCaP‑STEAP1 knockdown cells, except for c‑myc expression levels, where a cumulative effect between anti‑androgen treatment and STEAP1 knockdown was observed. The effect of STEAP1 knockdown alone or combined with anti‑androgens in c‑myc levels is required to be addressed in future studies.

Halorubrum pleomorphic virus-6 Membrane Fusion Is Triggered by an S-Layer Component of Its Haloarchaeal Host

(1) Background: Haloarchaea comprise extremely halophilic organisms of the Archaea domain. They are single-cell organisms with distinctive membrane lipids and a protein-based cell wall or surface layer (S-layer) formed by a glycoprotein array. Pleolipoviruses, which infect haloarchaeal cells, have an envelope analogous to eukaryotic enveloped viruses. One such member, Halorubrum pleomorphic virus 6 (HRPV-6), has been shown to enter host cells through virus-cell membrane fusion. The HRPV-6 fusion activity was attributed to its VP4-like spike protein, but the physiological trigger required to induce membrane fusion remains yet unknown. (2) Methods: We used SDS-PAGE mass spectroscopy to characterize the S-layer extract, established a proteoliposome system, and used R18-fluorescence dequenching to measure membrane fusion. (3) Results: We show that the S-layer extraction by Mg²⁺ chelating from the HRPV-6 host, Halorubrum sp. SS7-4, abrogates HRPV-6 membrane fusion. When we in turn reconstituted the S-layer extract from Hrr. sp. SS7-4 onto liposomes in the presence of Mg²⁺, HRPV-6 membrane fusion with the proteoliposomes could be readily observed. This was not the case with liposomes alone or with proteoliposomes carrying the S-layer extract from other haloarchaea, such as Haloferax volcanii. (4) Conclusions: The S-layer extract from the host, Hrr. sp. SS7-4, corresponds to the physiological fusion trigger of HRPV-6.

The Inhibitory Effect of Noscapine on the In Vitro Cathepsin G-Induced Collagen Expression in Equine Endometrium

Cathepsin G (CAT) is a protease released by neutrophils when forming neutrophil extracellular traps that was already associated with inducing type I collagen (COL1) in equine endometrium in vitro. Endometrosis is a fibrotic condition mainly characterized by COL1 deposition in the equine endometrium. The objective was to evaluate if noscapine (an alkaloid for cough treatment with anti-neoplastic and anti-fibrotic properties) would reduce COL1A2 transcription (evaluated by qPCR) and COL1 protein relative abundance (evaluated by western blot) induced by CAT in equine endometrial explants from follicular and mid-luteal phases treated for 24 or 48 h. The explants treated with CAT increased COL1 expression. Noscapine decreased COL1A2 transcription at both estrous cycle phases, but COL1 relative protein only at the follicular phase, both induced by CAT. Additionally, the noscapine anti-fibrotic action was found to be more effective in the follicular phase. The CAT treatment caused more fibrosis at the longest period of treatment, while noscapine acted better at the shortest time of treatment. Our results showed that noscapine could act as an anti-fibrotic drug in equine endometrosis by inhibiting CAT in vitro. Noscapine offers a new promising therapeutic tool for treating fibrosis as a single non-selective agent to be considered in the future.

Efficient generation of a single-copy eft-3p::TIR1::F2A:: BFP::AID*::NLS allele in the C. elegans ttTi5605 insertion site through recombination-mediated cassette exchange

The auxin-inducible degron (AID) system is a widely used system to conditionally deplete proteins. Using CRISPR/Cas9-based genome editing in C. elegans, we recently generated a set of single-copy, tissue-specific and pan-somatic TIR1-expressing strains carrying a BFP reporter inserted in single-copy into two commonly used, well-characterized genetic loci. However, we were unable to obtain a strain carrying a pan-somatic eft-3p::TIR1::F2A::BFP::AID*::NLS transgene inserted into the chromosome II ttTi5605 insertion site. Using recombination-mediated cassette exchange (RMCE) we were able to efficiently obtain this knock-in. The resulting strain displayed equivalent depletion of an AID*::GFP reporter compared to our previously generated eft-3p::TIR1::F2A::BFP::AID*::NLS transgene knocked into the chromosome I ttTi4348 insertion site. This work highlights the power of RMCE for generating new reagents for the AID system and provides an eft-3p::TIR1::F2A::BFP::AID*::NLS allele on chromosome II which will simplify genetic crossing schemes when using the AID system.

Loss of ephrin B2 receptor (EPHB2) sets lipid rheostat by regulating proteins DGAT1 and ATGL inducing lipid droplet storage in prostate cancer cells

Lipid droplet (LD) accumulation in cancer results from aberrant metabolic reprograming due to increased lipid uptake, diminished lipolysis and/or de novo lipid synthesis. Initially implicated in storage and lipid trafficking in adipocytes, LDs are more recently recognized to fuel key functions associated with carcinogenesis and progression of several cancers, including prostate cancer (PCa). However, the mechanisms controlling LD accumulation in cancer are largely unknown. EPHB2, a tyrosine kinase (TKR) ephrin receptor has been proposed to have tumor suppressor functions in PCa, although the mechanisms responsible for these effects are unclear. Given that dysregulation in TRK signaling can result in glutaminolysis we postulated that EPHB2 might have potential effects on lipid metabolism. Knockdown strategies for EPHB2 were performed in prostate cancer cells to analyze the impact on the net lipid balance, proliferation, triacylglycerol-regulating proteins, effect on LD biogenesis, and intracellular localization of LDs. We found that EPHB2 protein expression in a panel of human-derived prostate cancer cell lines was inversely associated with in vivo cell aggressiveness. EPHB2 silencing increased the proliferation of prostate cancer cells and concurrently induced de novo LD accumulation in both cytoplasmic and nuclear compartments as well as a "shift" on LD size distribution in newly formed lipid-rich organelles. Lipid challenge using oleic acid exacerbated the effects on the LD phenotype. Loss of EPHB2 directly regulated key proteins involved in maintaining lipid homeostasis including, increasing lipogenic DGAT1, DGAT2 and PLIN2 and decreasing lipolytic ATGL and PEDF. A DGAT1-specific inhibitor abrogated LD accumulation and proliferative effects induced by EPHB2 loss. In conclusion, we highlight a new anti-tumor function of EPHB2 in lipid metabolism through regulation of DGAT1 and ATGL in prostate cancer. Blockade of DGAT1 in EPHB2-deficient tumors appears to be effective in restoring the lipid balance and reducing tumor growth.

Noscapine Acts as a Protease Inhibitor of In Vitro Elastase-Induced Collagen Deposition in Equine Endometrium

Endometrosis is a reproductive pathology that is responsible for mare infertility. Our recent studies have focused on the involvement of neutrophil extracellular traps enzymes, such as elastase (ELA), in the development of equine endometrosis. Noscapine (NOSC) is an alkaloid derived from poppy opium with anticough, antistroke, anticancer, and antifibrotic properties. The present work investigates the putative inhibitory in vitro effect of NOSC on collagen type I alpha 2 chain (COL1A2) mRNA and COL1 protein relative abundance induced by ELA in endometrial explants of mares in the follicular or mid-luteal phases at 24 or 48 h of treatment. The COL1A2 mRNA was evaluated by qPCR and COL1 protein relative abundance by Western blot. In equine endometrial explants, ELA increased COL 1 expression, while NOSC inhibited it at both estrous cycle phases and treatment times. These findings contribute to the future development of new endometrosis treatment approaches. Noscapine could be a drug capable of preventing collagen synthesis in mare’s endometrium and facilitate the therapeutic approach.

Up-Regulation of Glycogen Synthesis and Degradation Enzyme Level Maintained Myocardial Glycogen in Huddling Brandt's Voles Under Cool Environments

Small mammals exhibit limited glucose use and glycogen accumulation during hypothermia. Huddling is a highly evolved cooperative behavioral strategy in social mammals, allowing adaptation to environmental cooling. However, it is not clear whether this behavior affects the utilization of glycogen in cold environments. Here, we studied the effects of huddling on myocardial glycogen content in Brandt’s voles (Lasiopodomys brandtii) under a mild cold environment (15°C). Results showed that (1) Compared to the control (22°C) group (CON), the number of glycogenosomes more than tripled in the cool separated group (CS) in both males and females; whereas the number of glycogenosomes increased in females but was maintained in males in the cool huddling group (CH). (2) Glycogen synthase (GS) activity in the CS group remained unchanged, whereas glycogen phosphorylase (GYPL) activity decreased, which mediated the accumulation of glycogen content of the CS group. (3) Both GS and GYPL activity increased which may contribute to the stability of glycogen content in CH group. (4) The expression levels of glucose transporters GLUT1 and GLUT4 increased in the CS group, accompanied by an increase in glucose metabolism. These results indicate that the reduced glycogen degradation enzyme level and enhanced glucose transport may lead to an increase in myocardial glycogen content of the separated voles under cool environment; while the up-regulation of glycogen synthesis and degradation enzyme level maintained myocardial glycogen content in the huddling vole.

Myeloperoxidase Inhibition Decreases the Expression of Collagen and Metallopeptidase in Mare Endometria under In Vitro Conditions

Neutrophils can originate neutrophil extracellular traps (NETs). Myeloperoxidase (MPO) is a peroxidase found in NETs associated to equine endometrosis and can be inhibited by 4-aminobenzoic acid hydrazide (ABAH). Metallopeptidases (MMPs) participate in extracellular matrix stability and fibrosis development. The objectives of this in vitro work were to investigate, in explants of mare's endometrium, (i) the ABAH capacity to inhibit MPO-induced collagen type I (COL1) expression; and (ii) the action of MPO and ABAH on the expression and gelatinolytic activity of MMP-2/-9. Explants retrieved from the endometrium of mares in follicular or mid-luteal phases were treated with MPO, ABAH, or their combination, for 24 or 48 h. The qPCR analysis measured the transcription of COL1A2, MMP2, and MMP9. Western blot and zymography were performed to evaluate COL1 protein relative abundance and gelatinolytic activity of MMP-2/-9, respectively. Myeloperoxidase elevated COL1 relative protein abundance at both treatment times in follicular phase (p < 0.05). The capacity of ABAH to inhibit MPO-induced COL1 was detected in follicular phase at 48 h (p < 0.05). The gelatinolytic activity of activated MMP-2 augmented in mid-luteal phase at 24 h after MPO treatment, but it was reduced with MPO+ABAH treatment. The activity of MMP-9 active form augmented in MPO-treated explants. However, this effect was inhibited by ABAH in the follicular phase at 48 h (p < 0.05). By inhibiting the pro-fibrotic effects of MPO, it might be possible to reduce the development of endometrosis. Metallopeptidase-2 might be involved in an acute response to MPO in the mid-luteal phase, while MMP-9 might be implicated in a prolonged exposition to MPO in the follicular phase.

The Inhibition of Cathepsin G on Endometrial Explants With Endometrosis in the Mare

Although proteases found in neutrophil extracellular traps (NETs) have antimicrobial properties, they also stimulate collagen type 1 (COL1) production by the mare endometrium, contributing for the development of endometrosis. Cathepsin G (CAT), a protease present in NETs, is inhibited by specific inhibitors, such as cathepsin G inhibitor I (INH; β-keto-phosphonic acid). Matrix metallopeptidases (MMPs) are proteases involved in the equilibrium of the extracellular matrix. The objective of this study was to investigate the effect of CAT and INH (a selective CAT inhibitor) on the expression of MMP-2 and MMP-9 and on gelatinolytic activity. In addition, the putative inhibitory effect of INH on CAT-induced COL1 production in mare endometrium was assessed. Endometrial explants retrieved from mares in follicular phase or midluteal phase were treated for 24 or 48 h with CAT, inhibitor alone, or both treatments. In explants, transcripts (quantitative polymerase chain reaction) of COL1A2, MMP2, and MMP9, as well as the relative abundance of COL1 protein (Western blot), and activity of MMP-2 and MMP-9 (zymography) were evaluated. The protease CAT induced COL1 expression in explants, at both estrous cycle phases and treatment times. The inhibitory effect of INH was observed on COL1A2 transcripts in follicular phase at 24-h treatment, and in midluteal phase at 48 h (P < 0.05), and on the relative abundance of COL protein in follicular phase and midluteal phase explants, at 48 h (P < 0.001). Our study suggests that MMP-2 might also be involved in an earlier response to CAT, and MMP-9 in a later response, mainly in the follicular phase. While the use of INH reduced CAT-induced COL1 endometrial expression, MMPs might be involved in the fibrogenic response to CAT. Therefore, in mare endometrium, the use of INH may be a future potential therapeutic means to reduce CAT-induced COL1 formation and to hamper endometrosis establishment.

Adipose Stromal Cells Enhance Decellularized Adipose Tissue Remodeling Through Multimodal Mechanisms

Decellularized adipose tissue (DAT) scaffolds represent a promising cell-instructive platform for soft tissue engineering. While recent work has highlighted that mesenchymal stromal cells, including adipose-derived stromal cells (ASCs), can be combined with decellularized scaffolds to augment tissue regeneration, the mechanisms involved require further study. The objective of this work was to probe the roles of syngeneic donor ASCs and host-derived macrophages in tissue remodeling of DAT scaffolds within an immunocompetent mouse model. Dual transgenic reporter mouse strains were employed to track and characterize the donor ASCs and host macrophages within the DAT implants. More specifically, ASCs isolated from dsRed mice were seeded on DAT scaffolds, and the seeded and unseeded control scaffolds were implanted subcutaneously into MacGreen transgenic mice for up to 8 weeks. ASC seeding was shown to augment cell infiltration into the DAT implants at 8 weeks, and this was linked to significantly enhanced angiogenesis relative to the unseeded controls. Immunohistochemical staining demonstrated long-term retention of the syngeneic donor ASCs over the duration of the 8-week study, providing evidence that the DAT scaffolds are a cell-supportive delivery platform. Notably, newly formed adipocytes within the DAT implants were not dsRed⁺, indicating that the donor ASCs supported fat formation through indirect mechanisms. Immunohistochemical tracking of host macrophages through costaining for enhanced green fluorescent protein with the macrophage marker Iba1 revealed that ASC seeding significantly increased the number of infiltrating macrophages within the DAT implants at 3 weeks, while the fraction of macrophages relative to the total cellular infiltrate was similar between the groups at 1, 3, and 8 weeks. Consistent with the tissue remodeling response that was observed, western blotting demonstrated that there was significantly augmented expression of CD163 and CD206, markers of constructive M2-like macrophages, within the ASC-seeded DAT implants. Overall, our results demonstrate that exogenous ASCs enhance tissue regeneration within DAT scaffolds indirectly through multimodal mechanisms that include host cell recruitment and immunomodulation. These data provide further evidence to support the use of decellularized scaffolds as a delivery platform for ASCs in tissue engineering.

Abnormal Social Interactions in a Drosophila Mutant of an Autism Candidate Gene: Neuroligin 3

Social interactions are typically impaired in neuropsychiatric disorders such as autism, for which the genetic underpinnings are very complex. Social interactions can be modeled by analysis of behaviors, including social spacing, sociability, and aggression, in simpler organisms such as Drosophila melanogaster. Here, we examined the effects of mutants of the autism-related gene neuroligin 3 (nlg3) on fly social and non-social behaviors. Startled-induced negative geotaxis is affected by a loss of function nlg3 mutation. Social space and aggression are also altered in a sex- and social-experience-specific manner in nlg3 mutant flies. In light of the conserved roles that neuroligins play in social behavior, our results offer insight into the regulation of social behavior in other organisms, including humans.

MitoTEMPOL, a mitochondrial targeted antioxidant, prevents sepsis-induced diaphragm dysfunction

Clinical studies indicate that sepsis-induced diaphragm dysfunction is a major contributor to respiratory failure in mechanically ventilated patients. Currently there is no drug to treat this form of diaphragm weakness. Sepsis-induced muscle dysfunction is thought to be triggered by excessive mitochondrial free radical generation; we therefore hypothesized that therapies that target mitochondrial free radical production may prevent sepsis-induced diaphragm weakness. The present study determined whether MitoTEMPOL, a mitochondrially targeted free radical scavenger, could reduce sepsis-induced diaphragm dysfunction. Using an animal model of sepsis, we compared four groups of mice: 1) sham-operated controls, 2) animals with sepsis induced by cecal ligation puncture (CLP), 3) sham controls given MitoTEMPOL (10 mg·kg^-1·day^-1 ip), and 4) CLP animals given MitoTEMPOL. At 48 h after surgery, we measured diaphragm force generation, mitochondrial function, proteolytic enzyme activities, and myosin heavy chain (MHC) content. We also examined the effects of delayed administration of MitoTEMPOL (by 6 h) on CLP-induced diaphragm weakness. The effects of MitoTEMPOL on cytokine-mediated alterations on muscle cell superoxide generation and cell size in vitro were also assessed. Sepsis markedly reduced diaphragm force generation. Both immediate and delayed MitoTEMPOL administration prevented sepsis-induced diaphragm weakness. MitoTEMPOL reversed sepsis-mediated reductions in mitochondrial function, activation of proteolytic pathways, and decreases in MHC content. Cytokines increased muscle cell superoxide generation and decreased cell size, effects that were ablated by MitoTEMPOL. MitoTEMPOL and other compounds that target mitochondrial free radical generation may be useful therapies for sepsis-induced diaphragm weakness.

The In Vitro Inhibitory Effect of Sivelestat on Elastase Induced Collagen and Metallopeptidase Expression in Equine Endometrium

Neutrophil extracellular traps (NETs) fight endometritis, and elastase (ELA), a protease found in NETs, might induce collagen type I (COL1) accumulation in equine endometrium. Metallopeptidases (MMPs) are involved in extracellular matrix balance. The aim was to evaluate the effects of ELA and sivelestat (selective elastase inhibitor) on MMP-2 and MMP-9 expression and gelatinolytic activity, as well as the potential inhibitory effect of sivelestat on ELA-induced COL1 in equine endometrium. Endometrial explants from follicular (FP) and mid-luteal (MLP) phases were treated for 24 or 48 h with ELA, sivelestat, and their combination. Transcripts of COL1A2, MMP2, and MMP9 were evaluated by qPCR; COL1 protein relative abundance by Western blot, and MMP-2 and MMP-9 gelatinolytic activity by zymography. In response to ELA treatment, there was an increase in MMP2 mRNA transcription (24 h) in active MMP-2 (48 h), both in FP, and in MMP9 transcripts in FP (48 h) and MLP (24 h) (p < 0.05). Sivelestat inhibited ELA-induced COL1A2 transcripts in FP (24 h) and MLP (24 h, 48 h) (p < 0.05). The sivelestat inhibitory effect was detected in MMP9 transcripts in FP at 48 h (p < 0.05), but proteases activity was unchanged. Thus, MMP-2 and MMP-9 might be implicated in endometrium fibrotic response to ELA. In mare endometrium, sivelestat may decrease ELA-induced COL1 deposition and hinder endometrosis development.

Priority Strategy of Intracellular Ca2+ Homeostasis in Skeletal Muscle Fibers During the Multiple Stresses of Hibernation

: Intracellular calcium (Ca²⁺) homeostasis plays a vital role in the preservation of skeletal muscle. In view of the well-maintained skeletal muscle found in Daurian ground squirrels (Spermophilus dauricus) during hibernation, we hypothesized that hibernators possess unique strategies of intracellular Ca²⁺ homeostasis. Here, cytoplasmic, sarcoplasmic reticulum (SR), and mitochondrial Ca²⁺ levels, as well as the potential Ca²⁺ regulatory mechanisms, were investigated in skeletal muscle fibers of Daurian ground squirrels at different stages of hibernation. The results showed that cytoplasmic Ca²⁺ levels increased in the skeletal muscle fibers during late torpor (LT) and inter-bout arousal (IBA), and partially recovered when the animals re-entered torpor (early torpor, ET). Furthermore, compared with levels in the summer active or pre-hibernation state, the activity and protein expression levels of six major Ca²⁺ channels/proteins were up-regulated during hibernation, including the store-operated Ca²⁺ entry (SOCE), ryanodine receptor 1 (RyR1), leucine zipper-EF-hand containing transmembrane protein 1 (LETM1), SR Ca²⁺ ATPase 1 (SERCA1), mitochondrial calcium uniporter complex (MCU complex), and calmodulin (CALM). Among these, the increased extracellular Ca²⁺ influx mediated by SOCE, SR Ca²⁺ release mediated by RyR1, and mitochondrial Ca²⁺ extrusion mediated by LETM1 may be triggers for the periodic elevation in cytoplasmic Ca²⁺ levels observed during hibernation. Furthermore, the increased SR Ca²⁺ uptake through SERCA1, mitochondrial Ca²⁺ uptake induced by MCU, and elevated free Ca²⁺ binding capacity mediated by CALM may be vital strategies in hibernating ground squirrels to attenuate cytoplasmic Ca²⁺ levels and restore Ca²⁺ homeostasis during hibernation. Compared with that in LT or IBA, the decreased extracellular Ca²⁺ influx mediated by SOCE and elevated mitochondrial Ca²⁺ uptake induced by MCU may be important mechanisms for the partial cytoplasmic Ca²⁺ recovery in ET. Overall, under extreme conditions, hibernating ground squirrels still possess the ability to maintain intracellular Ca²⁺ homeostasis.

Identification of protein changes in the blood plasma of lung cancer patients subjected to chemotherapy using a 2D-DIGE approach

A comparative analysis of blood samples (depleted of albumin and IgG) obtained from lung cancer patients before chemotherapy versus after a second cycle of chemotherapy was performed using two-dimensional difference gel electrophoresis (2D-DIGE). The control group consisted of eight patients with non-cancerous lung diseases, and the experimental group consisted of four adenocarcinoma (ADC) and four squamous cell carcinoma (SCC) patients. Analyses of gels revealed significant changes in proteins and/or their proteoforms between control patients and lung cancer patients, both before and after a second cycle of chemotherapy. Most of these proteins were related to inflammation, including acute phase proteins (APPs) such as forms of haptoglobin and transferrin, complement component C3, and clusterin. The variable expression of APPs can potentially be used for profiling lung cancer. The greatest changes observed after chemotherapy were in transferrin and serotransferrin, which likely reflect disturbances in iron turnover after chemotherapy-induced anaemia. Significant changes in plasma proteins between ADC and SCC patients were also revealed, suggesting use of plasma vitronectin as a potential marker of SCC.

Rhesus Brain Transcriptomic Landscape in an ex vivo Model of the Interaction of Live Borrelia Burgdorferi With Frontal Cortex Tissue Explants

Lyme neuroborreliosis (LNB) is the most dangerous manifestation of Lyme disease caused by the spirochete Borrelia burgdorferi which can reach the central nervous system most commonly presenting with lymphocytic meningitis; however, the molecular basis for neuroborreliosis is still poorly understood. We incubated explants from the frontal cortex of three rhesus brains with medium alone or medium with added live Borrelia burgdorferi for 6, 12, and 24 h and isolated RNA from each group was used for RNA sequencing with further bioinformatic analysis. Transcriptomic differences between the ex vivo model of live Borrelia burgdorferi with rhesus frontal cortex tissue explants and the controls during the progression of the infection were identified. A total of 2249, 1064, and 420 genes were significantly altered, of which 80.7, 52.9, and 19.8% were upregulated and 19.3, 47.1, 80.2% were downregulated at 6, 12, and 24 h, respectively. Gene ontology and KEGG pathway analyses revealed various pathways related to immune and inflammatory responses during the spirochete infection were enriched which is suggested to have a causal role in the pathogenesis of neurological Lyme disease. Moreover, we propose that the overexpressed FOLR2 which was demonstrated by the real-time PCR and western blotting could play a key role in neuroinflammation of the neuroborreliosis based on PPI analysis for the first time. To our knowledge, this is the first study to provide comprehensive information regarding the transcriptomic signatures that occur in the frontal cortex of the brain upon exposure to Borrelia burgdorferi, and suggest that FOLR2 is a promising target that is associated with neuroinflammation and may represent a new diagnostic or therapeutic marker in LNB.

Barrel Jellyfish (Rhizostoma pulmo) as Source of Antioxidant Peptides

The jellyfish Rhizostoma pulmo, Macrì 1778 (Cnidaria, Rhizostomae) undergoes recurrent outbreaks in the Mediterranean coastal waters, with large biomass populations representing a nuisance or damage for marine and maritime activities. A preliminary overview of the antioxidant activity (AA) of R. pulmo proteinaceous compounds is provided here based on the extraction and characterization of both soluble and insoluble membrane-fractioned proteins, the latter digested by sequential enzymatic hydrolyses with pepsin and collagenases. All jellyfish proteins showed significant AA, with low molecular weight (MW) proteins correlated with greater antioxidant activity. In particular, collagenase-hydrolysed collagen resulted in peptides with MW lower than 3 kDa, ranging 3⁻10 kDa or 10⁻30 kDa, with AA inversely proportional to MW. No cytotoxic effect was detected on cultured human keratinocytes (HEKa) in a range of protein concentration 0.05⁻20 μg/mL for all tested protein fractions except for soluble proteins higher than 30 kDa, likely containing the jellyfish venom compounds. Furthermore, hydrolyzed jellyfish collagen peptides showed a significantly higher AA and provided a greater protective effect against oxidative stress in HEKa than the hydrolyzed collagen peptides from vertebrates. Due to a high reproductive potential, jellyfish may represent a potential socioeconomic opportunity as a source of natural bioactive compounds, with far-reaching beneficial implications. Eventually, improvements in processing technology will promote the use of untapped marine biomasses in nutraceutical, cosmeceutical, and pharmaceutical fields, turning marine management problems into a more positive perspective.

Expression of the serotonin receptor 2B in uveal melanoma and effects of an antagonist on cell lines

Uveal melanoma (UM) is the most common primary tumor in the adult, and disseminates to the liver in half of patients. A 15-gene expression profile prognostic assay allows to determine the likelihood of metastasis in patients using their ocular tumor DNA, but a cure still remains to be discovered. The serotonin receptor 2B represents the discriminant gene of this molecular signature with the greatest impact on the prognosis of UM. However, its contribution to the metastatic potential of UM remains unexplored. The purpose of this study was to investigate the effects of a selective serotonin receptor 2B antagonist on cellular and molecular behaviours of UM cells. UM cell lines expressing high level of serotonin receptor 2B proteins were selected by Western blotting. The selective serotonin receptor 2B antagonist PRX-08066 was evaluated for its impact on UM cells using viability assays, phosphorylated histone H3 immunostainings, clonogenic assays, migration assays, invasion assays and membrane-based protein kinase phosphorylation antibody arrays. The pharmacological inhibition of the serotonin receptor 2B reduced the viability of UM cells and the population in mitosis, and impaired their clonogenicity and potential of migration. It also decreased the phosphorylation of kinases from signaling pathways classically activated by the serotonin receptor 2B, as well as kinases β-catenin, Proline-rich tyrosine kinase 2, and Signal transducer and activator of transcription 5. Our findings support a role for the serotonin receptor 2B in the proliferation and migration of UM cells, through activation of many signaling pathways such as WNT, Focal adhesion kinase and Janus kinase/STAT.

Genome-wide identification of natural RNA aptamers in prokaryotes and eukaryotes

RNAs are well-suited to act as cellular sensors that detect and respond to metabolite changes in the environment, due to their ability to fold into complex structures. Here, we introduce a genome-wide strategy called PARCEL that experimentally identifies RNA aptamers in vitro, in a high-throughput manner. By applying PARCEL to a collection of prokaryotic and eukaryotic organisms, we have revealed 58 new RNA aptamers to three key metabolites, greatly expanding the list of natural RNA aptamers. The newly identified RNA aptamers exhibit significant sequence conservation, are highly structured and show an unexpected prevalence in coding regions. We identified a prokaryotic precursor tmRNA that binds vitamin B2 (FMN) to facilitate its maturation, as well as eukaryotic mRNAs that bind and respond to FMN, suggesting FMN as the second RNA-binding ligand to affect eukaryotic expression. PARCEL results show that RNA-based sensing and gene regulation is more widespread than previously appreciated in different organisms.

Riboswitches recognize and respond to specific metabolites by altering gene expression. Here, the authors developed a high-throughput method (PARCEL) to experimentally identify RNA aptamers across transcriptomes.

The Ligand Binding Landscape of Diacylglycerol Kinases

Diacylglycerol kinases (DGKs) are integral components of signal transduction cascades that regulate cell biology through ATP-dependent phosphorylation of the lipid messenger diacylglycerol. Methods for direct evaluation of DGK activity in native biological systems are lacking and needed to study isoform-specific functions of these multidomain lipid kinases. Here, we utilize ATP acyl phosphate activity-based probes and quantitative mass spectrometry to define, for the first time, ATP and small-molecule binding motifs of representative members from all five DGK subtypes. We use chemical proteomics to discover an unusual binding mode for the DGKα inhibitor, ritanserin, including interactions at the atypical C1 domain distinct from the ATP binding region. Unexpectedly, deconstruction of ritanserin yielded a fragment compound that blocks DGKα activity through a conserved binding mode and enhanced selectivity against the kinome. Collectively, our studies illustrate the power of chemical proteomics to profile protein-small molecule interactions of lipid kinases for fragment-based lead discovery.

Differential responses of choroidal melanocytes and uveal melanoma cells to low oxygen conditions

PURPOSE

Tissue culture is traditionally performed at atmospheric oxygen concentration (21%), which induces hyperoxic stress, as endogenous physiologic oxygen tension found in tissues varies between 2% and 9%. This discrepancy may lead to misinterpretation of results and may explain why effects observed in vitro cannot always be reproduced in vivo and vice versa. Only a few studies have been conducted in low physiologic oxygen conditions to understand the development and differentiation of cells from the eye.

METHODS

The aim of this study was to investigate the growth and gene expression profile of melanocytes from the choroid permanently exposed to 21% (hyperoxic) or 3% (physiologic) oxygen with proliferation assays and DNA microarray. The cellular behavior of the melanocytes was then compared to that of cancer cells.

RESULTS

The gross morphology and melanin content of choroidal melanocytes changed slightly when they were exposed to 3% O₂, and the doubling time was statistically significantly faster. There was an increase in the percentage of choroidal melanocytes in the active phases of the cell cycle as observed by using the proliferation marker Ki67. The caveolin-1 senescence marker was not increased in choroidal melanocytes or uveal melanoma cells grown in hyperoxia. In comparison, the morphology of the uveal melanoma cells was similar between the two oxygen levels, and the doubling time was slower at 3% O₂. Surprisingly, gene expression profiling of the choroidal melanocytes did not reveal a large list of transcripts considerably dysregulated between the two oxygen concentrations; only the lactate transporter monocarboxylate transporter (MCT4) was statistically significantly upregulated at 3% O₂.

CONCLUSIONS

This study showed that the oxygen concentration must be tightly controlled in experimental settings, because it influences the subsequent cellular behavior of human choroidal melanocytes.

Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome

Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant to being combed flat. Until now, both simplex and familial UHS-affected case subjects with autosomal-dominant as well as -recessive inheritance have been reported. However, none of these case subjects were linked to a molecular genetic cause. Here, we report the identification of UHS-causative mutations located in the three genes PADI3 (peptidylarginine deiminase 3), TGM3 (transglutaminase 3), and TCHH (trichohyalin) in a total of 11 children. All of these individuals carry homozygous or compound heterozygous mutations in one of these three genes, indicating an autosomal-recessive inheritance pattern in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic causes of UHS and shed light on its pathophysiology and hair physiology in general.

Remote ischemic perconditioning attenuates ischemia/reperfusion-induced downregulation of AQP2 in rat kidney

Renal ischemia/reperfusion (I/R) can lead to impaired urine concentration ability and increased fractional excretion of sodium (FeNa). Local ischemic preconditioning improves renal water and sodium handling after I/R injury. Here, we investigate whether remote ischemic perconditioning (rIPeC) prevents dysregulation of renal water and salt handling in response to I/R injury and mechanisms that may be involved. Rats were subjected to right nephrectomy and randomized into a sham group or an I/R group. In the I/R group, rats were subjected to 37 min of renal ischemia and 3 days of reperfusion. rIPeC was applied to the abdominal aorta. Blood and urine were collected on day 3 postoperatively for clearance studies. The expression of aquaporins (AQPs) and the sodium transporter Na-K-ATPase were analyzed using immunoblotting and immunohistochemistry. I/R injury resulted in polyuria, increased FeNa, and decreased urine osmolality compared to sham rats. rIPeC attenuated the increase in FeNa and the decrease in urine osmolality. Expression of AQP1, AQP2, phosphorylated AQP2 (pAQP2), and Na-K-ATPase was downregulated in I/R rats. rIPeC attenuated the reductions in AQP2 and pAQP2 expression. Immunohistochemistry revealed decreased labeling of Na-K-ATPase in the outer medulla in I/R kidneys compared to kidneys from sham and I/R + rIPeC rats. After renal ischemia, the expression of Na-K-ATPase was substantially reduced in the outer medullary thick ascending limb. In conclusion, our data suggest that rIPeC might prevent dysregulation of renal water and salt handling via regulation of AQP2 expression and phosphorylation as well as via regulation of Na-K-ATPase expression in I/R rat kidneys.

Estradiol Elicits Proapoptotic and Antiproliferative Effects in Human Trophoblast Cells

During the first trimester of pregnancy, appropriate regulation of estradiol (E2) is essential for normal placental development. Previous studies demonstrate that premature elevation in E2 concentrations can lead to abnormal placentation, but have not fully elaborated the mechanism of this effect in the first-trimester trophoblast. Our aim was to determine whether E2 elicits trophoblast cell death or inhibits proliferation. The first-trimester human cytotrophoblast cell line HTR-8/SVneo was cultured in phenol red-free medium containing charcoal-stripped serum and treated with 17beta-E2 at concentrations between 0 and 100 nM. TUNEL and invasion assays indicated that E2 significantly increased cell death and reduced cell invasion at 10 nM, and nuclear Ki67 expression revealed that it decreased cell proliferation at 1 nM. A similar effect on cell death was observed in first-trimester placental explants. The E2 antagonist fulvestrant blocked all effects of E2. Immunohistochemistry showed that protein expression of proapoptotic caspases 3, 8, and 9 increased at E2 concentrations of 25 nM and greater, whereas expression of antiapoptotic BCL2-alpha decreased at E2 concentrations of 10 nM and greater. Additionally, treatments with estrogen receptor (ER) alpha-specific and ERbeta-specific agonists at concentrations between 0 and 1000 nM indicated that only ERalpha mediates E2's effects, although immunohistochemistry and Western immunoblotting showed that HTR-8/SVneo cells and placental explants express both ERalpha and ERbeta. Taken together, these findings reveal the interplay between elevated serum E2 and apoptosis in the first trimester of pregnancy. These factors could be associated with pregnancy complications including infertility and uteroplacental insufficiency.

Rapid and precise engineering of the Caenorhabditis elegans genome with lethal mutation co-conversion and inactivation of NHEJ repair

As in other organisms, CRISPR/Cas9 methods provide a powerful approach for genome editing in the nematode Caenorhabditis elegans. Oligonucleotides are excellent repair templates for introducing substitutions and short insertions, as they are cost effective, require no cloning, and appear in other organisms to target changes by homologous recombination at DNA double-strand breaks (DSBs). Here, I describe a methodology in C. elegans to efficiently knock in epitope tags in 8–9 days, using a temperature-sensitive lethal mutation in the pha-1 gene as a co-conversion marker. I demonstrate that 60mer oligos with 29 bp of homology drive efficient knock-in of point mutations, and that disabling nonhomologous end joining by RNAi inactivation of the cku-80 gene significantly improves knock-in efficiency. Homology arms of 35–80 bp are sufficient for efficient editing and DSBs up to 54 bp away from the insertion site produced knock-ins. These findings will likely be applicable for a range of genome editing approaches in C. elegans, which will improve editing efficiency and minimize screening efforts.

The necessity of and strategies for improving confidence in the accuracy of western blots

Western blotting is one of the most commonly used laboratory techniques for identifying proteins and semi-quantifying protein amounts; however, several recent findings suggest that western blots may not be as reliable as previously assumed. This is not surprising since many labs are unaware of the limitations of western blotting. In this manuscript, we review essential strategies for improving confidence in the accuracy of western blots. These strategies include selecting the best normalization standard, proper sample preparation, determining the linear range for antibodies and protein stains relevant to the sample of interest, confirming the quality of the primary antibody, preventing signal saturation and accurately quantifying the signal intensity of the target protein. Although western blotting is a powerful and indispensable scientific technique that can be used to accurately quantify relative protein levels, it is necessary that proper experimental techniques and strategies are employed.