Swimming alters some proteins of skeletal muscle tissue in rats with Alzheimer-like phenotype.

OBJECTIVES: Exercise training plays a significant role in preventing the destruction of central nerve neurons and muscle atrophy. The purpose of the present study was to investigate the effect of a period of swimming training on the expression of Neural cell adhesion molecule (NCAM), Semaphorin 3A (SEMA3A), and Profilin-1 (PFN1) proteins in the gastrocnemius muscle of Alzheimer-like phenotype rats. METHODS & MATERIALS: 32 Wistar males were (6 weeks of age) divided into four groups: Healthy Control (HC), Alzheimer-like phenotype's Control (AC), Healthy Training (HT), and Alzheimer-like phenotype's Training (AT). Alzheimer-like phenotypes were induced by beta-amyloid injection in the hippocampus. The training program consisted of 20 swimming sessions. Gastrocnemius muscle was removed after the intervention, and NCAM, SEMA3A, and PFN1 proteins were measured by the immunohistoflorescent method. RESULTS: The results showed that SEMA3A was increased (p = 0.001), and NCAM (p = 0.001), and PFN1 (p = 0.001) were decreased in AC compared to the HC group. Also, the results showed that NCAM (p = 0.001) and Pfn1 (p = 0.002) increased in the HT group compared to HC, and the NCAM (p = 0.001) and Pfn1 (p = 0.002) in AT group compared to AC (p = 0.001) increased significantly, while SEMA3A was reduced in the HT group compared to HC (p = 0.001) and AT group compared to AC (p = 0.001) CONCLUSION: Swimming effectively improves axon regeneration and neuronal formation in motor neurons and, therefore, can be an effective intervention to prevent and control the complications of Alzheimer-like phenotype.

Urinary extracellular vesicles prevent di-(2-ethylhexyl) phthalate-induced hypospadias by facilitating epithelial-mesenchymal transition via PFN2 delivery.

BACKGROUND: Urinary extracellular vesicles (EVs) have gained increasing interest in recent years as a potential source of noninvasive biomarkers of diseases related to urinary organs, but knowledge of the mechanism is still limited. The current study sought to clarify the mechanism of urinary EVs behind di-(2-ethylhexyl) phthalate (DEHP)-induced hypospadias via PFN2 delivery. METHOD: PFN2 expression in hypospadias was predicted by bioinformatics analysis. Following the induction of a hypospadias rat model using DEHP, rats were injected with EVs and/or underwent alteration of PFN2 and TGF-ß1 to assess their effects in vivo. The extracted rat urothelial cells (UECs) were co-cultured with EVs extracted from urine for in vitro experiments. RESULT: Microarray analysis predicted poor PFN2 expression in hypospadias. Upregulated PFN2 was found in urinary EVs, and restrained epithelial-mesenchymal transition (EMT) was observed in DEHP-exposed rats. Urinary EVs or PFN2 overexpression increased SMAD2, SMAD3, and TGF-ß1 protein expression and SMAD2 and SMAD3 phosphorylation in UECs and DEHP-exposed rats. UEC migration, invasion, and EMT were augmented by EV co-culture or upregulation of PFN2. Of note, the silencing of TGF-ß1 counterweighed the effect of PFN2. Besides, EV co-culture or overexpression of PFN2 or TGF-ß1 elevated the body weight, anal-genital distance (AGD), anal-genital index (AGI), and EMT of DEHP-exposed rats. CONCLUSION: In summary, urinary EVs activated the SMAD/TGF-ß1 pathway to induce EMT via PFN2 delivery, thus protecting against DEHP-induced hypospadias. (1) EMT in epithelial cells inhibits DEHP-induced hypospadias. (2) Urine-derived EVs deliver PFN2 to promote EMT in epithelial cells. (3) PFN2 can activate the SMAD/TGF-ß1 signaling axis. (4) Urine-derived EVs can transmit PFN2 to activate the SMAD/TGF-ß1 signaling axis, thus promoting EMT and inhibiting the occurrence of hypospadias.

Long noncoding RNA RMRP ameliorates doxorubicin-induced apoptosis by interacting with PFN1 in a P53-Dependent manner.

Doxorubicin (DOX) often causes acute or chronic cardiotoxicity during its application. LncRNA RMRP has been reported to be associated with several biological processes, such as cartilage-hair hypoplasia, but the relationship between RMRP and DOX-induced cardiotoxicity and chronic heart failure remains obscure. To test this hypothesis, GSE124401 and GSE149870 were processed for bioinformatics, and differentially expressed RMRP was then verified in the peripheral blood of 21 patients with heart failure compared with 7 controls. For in vitro validation, we used AC16 and HEK-293T cells. qPCR was used to detect the mRNA expression levels. The degree of apoptosis was detected by Western blot and TUNEL staining. Furthermore, the interaction between RMRP and PFN1 mRNA was verified by dual-luciferase reporter assays. In bioinformatics, RMRP showed significant downregulation, which was verified in clinical samples (p < 0.001) and DOX-treated AC16 models (p < 0.0001). Next, overexpression of RMRP could significantly alleviate DOX-induced apoptosis, and a potential downstream molecule of RMRP, PFN1, was also negatively associated with this change. RESCUE experiments further confirmed that PFN1 could be regulated by RMRP at both the RNA and protein levels, serving as a downstream mediator of RMRP's cardioprotective effects. This interaction was then confirmed to be a direct combination (p < 0.0001). Finally, we found that overexpression of RMRP could inhibit the expression of p53 and its phosphorylation level by suppressing PFN1. In summary, RMRP could exert cardioprotective effects via the PFN1/p53 axis, holding great promise for serving as a therapeutic target and potential biomarker.

Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda.

Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide-PEP-IA18-was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5 µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10 × MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.

Regulation of NF-κB- and STAT1-mediated plasmacytoid dendritic cell functions by A20.

Dendritic cells (DCs) are professional antigen presenting cells involved in the induction of T cell-mediated adaptive immunity. Plasmacytoid DCs (pDCs) originate from lymphoid precursors and produce type I interferons (IFNs) in response to pathogens. A20 is considered as a negative regulator of toll-like receptor (TLR) signaling pathways, in which Toxoplasma gondii- derived profilin (TgPRF) is a TLR11/12 ligand recognised by DCs to stimulate their maturation/activation. Little is known about contributions of A20 to changes in biological properties of pDCs. The present study, therefore, explored whether pDC functions are influenced by A20. To this end, bone marrow cells were isolated and cultured with Flt3L to attain CD8DCs, CD11bDCs and pDCs and followed by challenge with TgPRP in the presence or absence of A20 siRNA. Expression of maturation markers were analysed by flow cytometry, and secretion of inflammatory cytokines by ELISA, cell migration by a transwell migration assay and expression of signalling molecules by western blotting. As a result, treatment with A20 siRNA enhanced activations of IκB-α and STAT-1, leading to increases in expressions of maturation markers and cytokine productions as well as migration of TgPRP-treated pDCs, while mature CD11bDCs produced at higher levels of TNF-α and IL-6 only. In addition, functions of CD8DCs remained unaltered following A20 silencing. The effects of A20 on pDC maturation and activation were completely abolished by IKK inhibitor and partially blunted by fludarabine. In conclusion, the inhibitory effects of A20 on pDC functions are expected to affect the immune response in T. gondii infection.

Cofilin drives rapid turnover and fluidization of entangled F-actin.

The shape of most animal cells is controlled by the actin cortex, a thin network of dynamic actin filaments (F-actin) situated just beneath the plasma membrane. The cortex is held far from equilibrium by both active stresses and polymer turnover: Molecular motors drive deformations required for cell morphogenesis, while actin-filament disassembly dynamics relax stress and facilitate cortical remodeling. While many aspects of actin-cortex mechanics are well characterized, a mechanistic understanding of how nonequilibrium actin turnover contributes to stress relaxation is still lacking. To address this, we developed a reconstituted in vitro system of entangled F-actin, wherein the steady-state length and turnover rate of F-actin are controlled by the actin regulatory proteins cofilin, profilin, and formin, which sever, recycle, and assemble filaments, respectively. Cofilin-mediated severing accelerates the turnover and spatial reorganization of F-actin, without significant changes to filament length. We demonstrate that cofilin-mediated severing is a single-timescale mode of stress relaxation that tunes the low-frequency viscosity over two orders of magnitude. These findings serve as the foundation for understanding the mechanics of more physiological F-actin networks with turnover and inform an updated microscopic model of single-filament turnover. They also demonstrate that polymer activity, in the form of ATP hydrolysis on F-actin coupled to nucleotide-dependent cofilin binding, is sufficient to generate a form of active matter wherein asymmetric filament disassembly preserves filament number despite sustained severing.

Molecular mechanism of Arabidopsis thaliana profilins as antifungal proteins.

BACKGROUND: It remains an open question whether plant phloem sap proteins are functionally involved in plant defense mechanisms. METHODS: The antifungal effects of two profilin proteins from Arabidopsis thaliana, AtPFN1 and AtPFN2, were tested against 11 molds and 4 yeast fungal strains. Fluorescence profiling, biophysical, and biochemical analyses were employed to investigate their antifungal mechanism. RESULTS: Recombinant AtPFN1 and AtPFN2 proteins, expressed in Escherichia coli, inhibited the cell growth of various pathogenic fungal strains at concentrations ranging from 10 to 160 µg/mL. The proteins showed significant intracellular accumulation and cell-binding affinity for fungal cells. Interestingly, the AtPFN proteins could penetrate the fungal cell wall and membrane and act as inhibitors of fungal growth via generation of cellular reactive oxygen species and mitochondrial superoxide. This triggered the AtPFN variant-induced cell apoptosis, resulting in morphological changes in the cells. CONCLUSION: PFNs may play a critical role as antifungal proteins in the Arabidopsis defense system against fungal pathogen attacks. GENERAL SIGNIFICANCE: The present study indicates that two profilin proteins, AtPFN1 and AtPFN2, can act as natural antimicrobial agents in the plant defense system.

Immune adjuvant effect of a Toxoplasma gondii profilin-like protein in autologous whole-tumor-cell vaccination in mice.

Profilin-like protein in Toxoplasma gondii (TgPLP) is a Toll-like receptor (TLR) agonist. In this study, we investigated whether TgPLP has an adjuvant effect on immune function in autologous whole-tumor-cell vaccine (AWV) treatment. Mice vaccinated with AWV together with recombinant TgPLP protein had smaller CT26 tumors and increased survival. TgPLP treatment strongly increased the production of IL-12 through MyD88 signaling and several chemokines, including CCL5, CCL12, and XCL1, in bone marrow-derived macrophages (BMMs). In addition, TgPLP increased the phagocytosis of tumor cells by BMMs and promoted immune cell mobility on a tumor-matrigel scaffold. TgPLP triggered immune responses as demonstrated by increased expression of antigen presenting cell markers (MHC class I and II, B7.1, and B7.2) in BMMs and increased IL-12 and IFN-γ expression in mice. Mice vaccinated with AWV and TgPLP had more immune cells (CD4+ and CD8+ T cells, natural killer cells, and macrophages) in the spleen and higher total IgG and IgG2a concentrations in the blood than mice vaccinated with AWV alone. These findings suggest that TgPLP is a TLR-based vaccine adjuvant that enhances antitumor immune responses during vaccination with AWV.

Probing plasmodesmata function with biochemical inhibitors.

To investigate plasmodesmata (PD) function, a useful technique is to monitor the effect on cell-to-cell transport of applying an inhibitor of a physiological process, protein, or other cell component of interest. Changes in PD transport can then be monitored in one of several ways, most commonly by measuring the cell-to-cell movement of fluorescent tracer dyes or of free fluorescent proteins. Effects on PD structure can be detected in thin sections of embedded tissue observed using an electron microscope, most commonly a Transmission Electron Microscope (TEM). This chapter outlines commonly used inhibitors, methods for treating different tissues, how to detect altered cell-to-cell transport and PD structure, and important caveats.

Immunoenhancing effects of Montanide ISA oil-based adjuvants on recombinant coccidia antigen vaccination against Eimeria acervulina infection.

The current study was conducted to investigate the immunoenhancing effects of Montanide adjuvants on protein subunit vaccination against avian coccidiosis. Broiler chickens were immunized subcutaneously with a purified Eimeria acervulina recombinant profilin protein, either alone or mixed with one of four adjuvants (ISA 70 VG, ISA 71 VG, ISA 201 VG or ISA 206 VG), and body weight gains, fecal oocyst shedding, and humoral and innate immune responses were evaluated following oral challenge infection with live E. acervulina oocysts. Immunization with profilin plus ISA 70 VG or ISA 71 VG increased body weight gains compared with vaccination with profilin alone. Profilin plus ISA 71 VG also reduced fecal oocyst shedding compared with vaccination in the absence of adjuvant. All adjuvants enhanced profilin serum antibody titers. Increased levels of gene transcripts encoding IL-2, IL-10, IL-17A, and IFN-gamma, but decreased levels of IL-15 mRNAs, were seen in intestinal intraepithelial lymphocytes of chickens immunized with profilin plus adjuvants compared with immunization with profilin alone. Finally, increased infiltration of lymphocytes, especially CD8(+) lymphocytes at the site of immunization was observed in birds given profilin plus ISA 71 VG compared with profilin alone. These results demonstrate that vaccination with the E. acervulina profilin subunit vaccine in combination with Montanide adjuvants enhances protective immunity against avian coccidiosis.

Component-resolved diagnosis of pollen allergy based on skin testing with profilin, polcalcin and lipid transfer protein pan-allergens.

BACKGROUND: Allergy diagnosis needs to be improved in patients suffering from pollen polysensitization due to the existence of possible confounding factors in this type of patients. OBJECTIVE: To evaluate new diagnostic strategies by comparing skin responses to pan-allergens and conventional allergenic extracts with specific IgE (sIgE) to purified allergen molecules. METHODS: One thousand three hundred and twenty-nine pollen-allergic patients were diagnosed by a combination of an in vitro method with a panel of 13 purified allergens, including major allergens and pan-allergens, using a high-capacity screening technology (ADVIA-Centaur) and skin prick test (SPT) to pan-allergens and conventional extracts. RESULTS: There was a high concordance (kappa index) between in vitro (sIgE to major allergens) and in vivo (SPT to conventional extracts) methods in patients who were not sensitized to pan-allergens, but SPT with conventional extracts failed to diagnose patients with sensitization to pan-allergens. In patients who were simultaneously sensitized to polcalcins and profilins, there was a duplication both in the number of sensitizations to major allergens and in the years of disease evolution. There was a statistical association between sensitization to profilins and/or lipid transfer proteins and food allergy (P<0.0001). CONCLUSION: The novel diagnostic strategy has proven to be a valuable tool in daily clinical practice. Introduction of routine SPT to pan-allergens is a simple and feasible way of improving diagnostic efficacy. Patients sensitized to pan-allergens should be tested by an adequate panel of allergenic molecules in order to identify the allergens that are responsible for the allergic disease.

Effect of profilin on actin critical concentration: a theoretical analysis.

To explain the effect of profilin on actin critical concentration in a manner consistent with thermodynamic constraints and available experimental data, we built a thermodynamically rigorous model of actin steady-state dynamics in the presence of profilin. We analyzed previously published mechanisms theoretically and experimentally and, based on our analysis, suggest a new explanation for the effect of profilin. It is based on a general principle of indirect energy coupling. The fluctuation-based process of exchange diffusion indirectly couples the energy of ATP hydrolysis to actin polymerization. Profilin modulates this coupling, producing two basic effects. The first is based on the acceleration of exchange diffusion by profilin, which indicates, paradoxically, that a faster rate of actin depolymerization promotes net polymerization. The second is an affinity-based mechanism similar to the one suggested in 1993 by Pantaloni and Carlier although based on indirect rather than direct energy coupling. In the model by Pantaloni and Carlier, transformation of chemical energy of ATP hydrolysis into polymerization energy is regulated by direct association of each step in the hydrolysis reaction with a corresponding step in polymerization. Thus, hydrolysis becomes a time-limiting step in actin polymerization. In contrast, indirect coupling allows ATP hydrolysis to lag behind actin polymerization, consistent with experimental results.

Profilin induces lamellipodia by growth factor-independent mechanism.

Profilin has been implicated in cell motility and in a variety of cellular processes, such as membrane extension, endocytosis, and formation of focal complexes. In vivo, profilin replenish the pool of ATP-actin monomers by increasing the rate of nucleotide exchange of ADP-actin for ATP-actin, promoting the incorporation of new actin monomers at the barbed end of actin filaments. For this report, we generated a membrane-permeable version of profilin I (PTD4-PfnI) for the alteration of intracellular profilin levels taking advantage of the protein transduction technique. We show that profilin I induces lamellipodia formation independently of growth factor presence in primary bovine trabecular meshwork (BTM) cells. The effects are time- and concentration-dependent and specific to the profilin I isoform. Profilin II, the neuronal isoform, failed to extend lamellipodia in the same degree as profilin I. H133S, a mutation in the polyproline binding domain, showed a reduced ability to induce lamellipodia. H199E, mutation in the actin binding domain failed to induce membrane spreading and inhibit fetal bovine serum (FBS) -induced lamellipodia extension. Incubation with a synthetic polyproline domain peptide (GP5)3, fused to a transduction domain, abolished lamellipodia induction by profilin or FBS. Time-lapse microscopy confirmed the effects of profilin on lamellipodia extension with a higher spreading velocity than FBS. PTD4-Pfn I was found in the inner lamellipodia domain, at the membrane leading edge where it colocalizes with endogenous profilin. While FBS-induced lamellipodia formation activates Rac1, PTD4-Pfn I stimulation did not induce Rac1 activation. We propose a role of profilin I favoring lamellipodia formation by a mechanism downstream of growth factor.

Hypotensive effect of profilin on rabbit intraocular pressure.

Ocular hypertension is a negative process that occurs within the eye and is the main risk factor to develop glaucoma, a progressive loss of vision due to degeneration of retinal ganglion cells. The protein transduction technique allows a cargo to cross biological membranes. Using this technique we have previously shown that a membrane permeable version of profilin I (PTD4-profilin) increased aqueous humour outflow facility. Here we have investigated if a topical application of PTD4-profilin was able to modify intraocular pressure in rabbits. 10 microM PTD4-profilin (10 microL), reduced intraocular pressure by 20% compared to the control vehicle, this value being in the range of other commercial drugs, which produced intraocular pressure reductions between 18 and 35%. The mean-time effect for PTD4-profilin was 6.8 h and was also in the same range as commercial products that provided values between 4.3 and 5.5 h. According to the results presented here we propose PTD4-profilin as a new approach for the treatment of ocular hypertension and PTD4 as a new strategy to facilitate the penetration of molecules into the eye.

The roles of ATP in the dynamics of the actin filaments of the cytoskeleton.

In contrast to the actin filaments of muscle, which are stabilized by special proteins, actin filaments of the cytoskeleton are highly dynamic. In vitro observations at room temperature have led to the conclusion that the hydrolysis of ATP, which accompanies the polymerization of ATP-containing monomers, destabilizes the filaments of the actin skeleton. Many functions of this skeleton, such as signal transduction, the anchoring of cell adhesion complexes, and the transfer and generation of pulling forces, can obviously only be adequately performed by stable filaments. Here it is assumed that, at room temperature, the interaction of ADP-containing monomers is impaired by complexed water molecules that partly shield the binding surfaces. The possibility that, at higher temperatures, the interaction of the monomers is strong enough to prevent spontaneous filament depolymerization is explored. Using mechanical models that take into account binding forces and energies, the polymerization cycle expected under these conditions is described. It is shown that ATP serves primarily to prevent incorrect binding of the incoming monomer to the end of the filament ('adjusted fit'). In addition, it provides the free energy needed for disassembly of the expected stable filaments.

Caenorhabditis elegans expresses three functional profilins in a tissue-specific manner.

Profilins are actin binding proteins, which also interact with polyphosphoinositides and proline-rich ligands. On the basis of the genome sequence, three diverse profilin homologues (PFN) are predicted to exist in Caenorhabditis elegans. We show that all three isoforms PFN-1, PFN-2, and PFN-3 are expressed in vivo and biochemical studies indicate they bind actin and influence actin dynamics in a similar manner. In addition, they bind poly(L-proline) and phosphatidylinositol 4,5-bisphosphate micelles. PFN-1 is essential whereas PFN-2 and PFN-3 are nonessential. Immunostainings revealed different expression patterns for the profilin isoforms. In embryos, PFN-1 localizes in the cytoplasm and to the cell-cell contacts at the early stages, and in the nerve ring during later stages. During late embryogenesis, expression of PFN-3 was specifically detected in body wall muscle cells. In adult worms, PFN-1 is expressed in the neurons, the vulva, and the somatic gonad, PFN-2 in the intestinal wall, the spermatheca, and the pharynx, and PFN-3 localizes in a striking dot-like fashion in body wall muscle. Thus the model organism Caenorhabditis elegans expresses three profilin isoforms and is the first invertebrate animal with tissue-specific profilin expression.