Profilin1 biology and its mutation, actin(g) in disease

Aggregates associated with amyotrophic lateral sclerosis sequester the actin-binding protein profilin 2

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease characterized by the degeneration of upper and lower motoneurons. The four most frequently mutated genes causing familial ALS (fALS) are C9orf72, FUS, SOD1, and TARDBP. Some of the related wild-type proteins comprise intrinsically disordered regions (IDRs) which favor their assembly in liquid droplets-the biophysical mechanism behind the formation of physiological granules such as stress granules (SGs). SGs assemble and dissolve dependent on the cellular condition. However, it has been suggested that transition from reversible SGs to irreversible aggregates contributes to the toxic properties of ALS-related mutated proteins. Sequestration of additional proteins within these aggregates may then result in downstream toxicity. While the exact downstream mechanisms remain elusive, rare ALS-causing mutations in the actin binding protein profilin 1 suggest an involvement of the actin cytoskeleton. Here, we hypothesize that profilin isoforms become sequestered in aggregates of ALS-associated proteins which induce subsequent dysregulation of the actin cytoskeleton. Interestingly, localization of neuronal profilin 2 in SGs was more pronounced compared with the ubiquitously expressed profilin 1. Accordingly, FUS and C9orf72 aggregates prominently sequestered profilin 2 but not profilin 1. Moreover, we observed a distinct sequestration of profilin 2 and G-actin to C9orf72 aggregates in different cellular models. On the functional level, we identified dysregulated actin dynamics in cells with profilin 2-sequestering aggregates. In summary, our results suggest a more common involvement of profilins in ALS pathomechanisms than indicated from the rarely occurring profilin mutations.

Endothelial cytoskeleton in mechanotransduction and vascular diseases

The cytoskeleton is an important structural component that regulates various aspects of cell morphology, movement, and intracellular signaling. It plays a pivotal role in the cellular response to biomechanical stimuli, particularly in endothelial cells, which are critical for vascular homeostasis and the pathogenesis of cardiovascular diseases. Mechanical forces, such as shear and tension, activate intracellular signaling cascades that regulate transcription, translation, and cellular behaviors. Despite extensive research into cytoskeletal functions, the precise mechanisms by which the cytoskeleton transduces mechanical signals remain incompletely understood. This review focuses on the role of cytoskeletal components in membrane, cytoplasm, and nucleus in mechanotransduction, with an emphasis on their structure, mechanical and biological behaviors, dynamic interactions, and response to mechanical forces. The collaboration between membrane cytoskeleton, cytoplasmic cytoskeleton, and nucleoskeleton is indispensable for endothelial cells to respond to mechanical stimuli. Understanding their mechanoresponsive mechanisms is essential for advancing therapeutic strategies for cardiovascular diseases.

Amine-Functionalized Gellan Gum-Based Hydrogel Loaded with Adipose Stem Cell-Derived Small Extracellular Vesicles: An In Vitro Proof of Concept for Enhancing Diabetic Foot Ulcer Healing

Diabetic foot ulcers (DFUs) are chronic wounds and a common complication of diabetes. A promising strategy in the treatment of DFUs involves the use of stem cell derivatives, such as small extracellular vesicles (sEVs), which can enhance cell proliferation and reduce inflammation while avoiding immunogenic responses. In this study, we evaluated the ability of adipose mesenchymal stem cell- (ASC)-derived sEVs to enhance the proliferation of human fibroblasts, which play a crucial role in wound regenerative processes. To mimic the inflammatory environment of DFUs, fibroblasts were cultured into the gellan gum (GG) modified with ethylenediamine (EDA) hydrogel scaffolds loaded with ASC-derived sEVs, under pro-inflammatory cytokines. Our comparative analysis demonstrated that sEVs loaded in GG-EDA hydrogel improved fibroblast viability in pro-inflamed conditions while retaining the anti-inflammatory and immunomodulatory properties of their cells of origin. By modulating the gene expression profile of fibroblasts to promote cell proliferation, wound healing and re-epithelialization, our system presents a promising therapeutic strategy for DFU healing.

Peripherally-restricted recurrent infection by engineered E. coli strain modulates hippocampal proteome promoting memory impairments in a rat model

Commensal bacteria that breach endothelial barrier has been reported to induce low grade chronic inflammation producing disease symptoms in major peripheral tissues. In this study, we investigated the role of genetically modified cellular invasive form of commensal E. coli K12 (SK3842) in cognitive impairment. Low-grade systemic infection model was developed using recurring peripheral inoculation of live bacteria in Wistar rats. To examine memory parameters, Novel object recognition test and Radial arm maze test were performed. Differential protein expression profiling of rat hippocampus was carried out using LC-MS/MS and subsequently quantified using SWATH. HBA1/2, NEFH, PFN1 and ATP5d were chosen for validation using quantitative RT-PCR. Results showed drastic decline in Recognition memory of the SK3842 infected rats. Reference and Working Memory of the infected group were also significantly reduced in comparison to control group. Proteome analysis using LC-MS/MS coupled with SWATH revealed differential expression of key proteins that are crucial for the maintenance of various neurological functions. Moreover, expression of NEFH and PFN1transcripts were found to be in line with the proteomics data. Protein interaction network of these validated proteins generated by STRING database converged to RhoA protein. Thus, the present study establishes an association between peripheral infection of a hippocampal protein network dysregulation and overall memory decline.

CqProfilin enhances WSSV infection by promoting viral intracellular transport through binding to both viral nucleocapsid and actin cytoskeleton

White spot syndrome virus (WSSV) is a large nuclear-replicating DNA virus of crustaceans such as shrimp and crayfish; however, the molecular mechanisms facilitating its transport from the invasion site to the cell nucleus have not yet been well elucidated. In this study, a CqProfilin (CqPFN) with a conserved PROF domain was identified from the red claw crayfish Cherax quadricarinatus. CqPFN was ubiquitously expressed in all examined tissues and hemocyte, with the highest levels in the hemocyte, followed by hematopoietic tissue (Hpt) from which the hemocyte were derived in crayfish. The transcript of WSSV genes such as IE1 and VP28 was obviously decreased both in vivo in hemocyte and Hpt, as well as in vitro in cultured Hpt cells, after CqPFN gene silencing; in contrast, the expression of viral genes was significantly increased by the introduction of a recombinant CqPFN protein in Hpt cells in vitro. Moreover, CqPFN was clearly colocalized with the main viral nucleocapsid protein VP664 and F-actin cytoskeleton, respectively, during the early stage of WSSV infection in Hpt cells. In addition, CqPFN was confirmed to interact with a truncated VP6642,405-2,535 and another viral nucleocapsid protein VP15 of WSSV and Cqβ-Actin from Hpt by co-immunoprecipitation assays. Further studies found that VP664 also colocalized with F-actin in the Hpt cell cytoplasm after WSSV infection, suggesting that the actin cytoskeleton was involved in the intracellular transport of incoming viral nucleocapsid. Taken together, CqPFN might combine with the actin cytoskeleton to promote WSSV infection through binding with viral nucleocapsid proteins VP664 and VP15, promoting intracellular transport of viral incoming nucleocapsid for further releasing genome into the nucleus for transcription. Collectively, these results provided an understanding of the WSSV pathogenesis, which will contribute to the development of an antiviral strategy against WSSV disease.

Human birth tissue products as a non-opioid medicine to inhibit post-surgical pain

Pain after surgery causes significant suffering. Opioid analgesics cause severe side effects and accidental death. Therefore, there is an urgent need to develop non-opioid therapies for managing post-surgical pain. Local application of Clarix Flo (FLO), a human amniotic membrane (AM) product, attenuated established post-surgical pain hypersensitivity without exhibiting known side effects of opioid use in mice. This effect was achieved through direct inhibition of nociceptive dorsal root ganglion (DRG) neurons via CD44-dependent pathways. We further purified the major matrix component, the heavy chain-hyaluronic acid/pentraxin 3 (HC-HA/PTX3) from human AM that has greater purity and water solubility than FLO. HC-HA/PTX3 replicated FLO-induced neuronal and pain inhibition. Mechanistically, HC-HA/PTX3-induced cytoskeleton rearrangements to inhibit sodium current and high-voltage activated calcium current on nociceptive DRG neurons, suggesting it is a key bioactive component mediating pain relief. Collectively, our findings highlight the potential of naturally derived biologics from human birth tissues as an effective non-opioid treatment for post-surgical pain. Moreover, we unravel the underlying neuronal mechanisms of pain inhibition induced by FLO and HC-HA/PTX3.

Clearing Amyloid-Beta by Astrocytes: The Role of Rho GTPases Signaling Pathways as Potential Therapeutic Targets

Astrocytes, vital support cells in the central nervous system (CNS), are crucial for maintaining neuronal health. In neurodegenerative diseases such as Alzheimer's disease (AD), astrocytes play a key role in clearing toxic amyloid-β (Aβ) peptides. Aβ, a potent neuroinflammatory trigger, stimulates astrocytes to release excessive glutamate and inflammatory factors, exacerbating neuronal dysfunction and death. Recent studies underscore the role of Rho GTPases-particularly RhoA, Rac1, and Cdc42-in regulating Aβ clearance and neuroinflammation. These key regulators of cytoskeletal dynamics and intracellular signaling pathways function independently through distinct mechanisms but may converge to modulate inflammatory responses. Their influence on astrocyte structure and function extends to regulating endothelin-converting enzyme (ECE) activity, which modulates vasoactive peptides such as endothelin-1 (ET-1). Through these processes, Rho GTPases impact vascular permeability and neuroinflammation, contributing to AD pathogenesis by affecting both Aβ clearance and cerebrovascular interactions. Understanding the interplay between Rho GTPases and the cerebrovascular system provides fresh insights into AD pathogenesis. Targeting Rho GTPase signaling pathways in astrocytes could offer a promising therapeutic approach to mitigate neuroinflammation, enhance Aβ clearance, and slow disease progression, ultimately improving cognitive outcomes in AD patients.

Exploring Molecular Alterations in Breast Cancer Among Indian Women Using Label-Free Quantitative Serum Proteomics

The clinical data indicate that diverse parameters characterize breast cancer patients in India, including age at presentation, risk factors, outcomes, and behavior. Alarming incidence and mortality rates emphasize the crucial need for early screening measures to combat breast cancer-related deaths effectively. Quantitative proteomic approaches prove pivotal in predicting cancer prognosis, analyzing protein expression patterns tied to disease aggressiveness and metastatic potential, and facilitating conversant therapy selection. Thus, this study was envisioned with the goal of identifying protein markers associated with breast cancer in Indian women, which could potentially be developed as diagnostic tools and therapeutic targets in the future. Applying label-free proteomic quantitation method and statistical analysis, several differentially expressed proteins (DEPs) were identified in the serum of breast cancer patients compared to controls, including SBSN, ANG, PCOLCE, and WFDC3 (upregulated), and PFN1, FLNA, and DSG2 (downregulated). The expression of SBSN was also validated by western blotting. Statistical methods were employed to proteomic expression data, which highlighted the ability of DEPs to distinguish between breast cancer and control samples. Conclusively, this study recognizes prospective biomarkers for breast cancer among Indian women and highlights the requisite of in-depth functional studies to elucidate their precise roles in breast cancer development. We particularly emphasize on SBSN and PFN1, as these proteins were observed to be progressively overexpressed and under expressed, respectively, in breast cancer samples compared to control samples, ranging from early-stage to metastatic cases.

Human birth tissue products as a non-opioid medicine to inhibit post-surgical pain

Pain after surgery causes significant suffering. Opioid analgesics cause severe side effects and accidental death. Therefore, there is an urgent need to develop non-opioid therapies for managing post-surgical pain. Local application of Clarix Flo (FLO), a human amniotic membrane (AM) product, attenuated established post-surgical pain hypersensitivity without exhibiting known side effects of opioid use in mice. This effect was achieved through direct inhibition of nociceptive dorsal root ganglion (DRG) neurons via CD44-dependent pathways. We further purified the major matrix component, the heavy chain-hyaluronic acid/pentraxin 3 (HC-HA/PTX3) from human AM that has greater purity and water solubility than FLO. HC-HA/PTX3 replicated FLO-induced neuronal and pain inhibition. Mechanistically, HC-HA/PTX3 induced cytoskeleton rearrangements to inhibit sodium current and high-voltage activated calcium current on nociceptive neurons, suggesting it is a key bioactive component mediating pain relief. Collectively, our findings highlight the potential of naturally derived biologics from human birth tissues as an effective non-opioid treatment for post-surgical pain. Moreover, we unravel the underlying mechanisms of pain inhibition induced by FLO and HC-HA/PTX3.

A new biomarker in the diagnosis and prognosis of pulmonary thromboembolism: Serum profilin-1

Objective

Pulmonary Thromboembolism (PTE) is one of the major cardiovascular diseases with high morbidity and mortality. Early diagnosis and accurate prognosis are essential in clinical management. This study aimed to investigate the efficacy of serum Profilin-1(PFN1) in diagnosing and prognosis PTE.

Materials and methods

This study was conducted on patients older than 18 diagnosed with PTE and healthy volunteers with similar sociodemographic characteristics who applied to the emergency department between March 2022 and March 2023.

Results

In the study, 102 patients diagnosed with PTE were in the patient group, and 64 healthy volunteers were in the control group. The median PFN1 level of the patient group was 2878 (124-5001) pg/mL, while the median PFN1 level of the control group was 579 (125-5001) pg/mL. The PFN1 level of the patient group was significantly higher than the control group (p < 0.001). PFN1 levels of 984.46 pg/mL and above had 76.47 % sensitivity and 79.69 % specificity in diagnosing PTE (AUC: 0.817; CI: 0.750-0.873; p < 0.0001). The median PFN1 level of patients with mortality was 5001 (1793.3-5001) pg/mL, while the median PFN1 level of patients without mortality was 1858 (124-5001) pg/mL. PFN1 levels of patients who developed mortality were significantly higher than those who did not develop mortality (p < 0.001). PFN1 levels of 3292.1 pg/mL and above had 90.91 % sensitivity and 71.25 % specificity in PTE prognosis (AUC: 0.861; CI: 0.778-0.921; p < 0.0001).

Conclusion

Serum Profilin-1 levels are helpful as a diagnostic and prognostic indicator in PTE.

PFN1 Knockdown Aggravates Mitophagy to Retard Lung Adenocarcinoma Initiation and M2 Macrophage Polarization

Tumor-associated macrophages (TAM) are considered as crucial influencing factors of lung adenocarcinoma (LUAD) carcinogenesis and metastasis. Profilin 1 (PFN1) has been proposed as a potent driver of migration and drug resistance in LUAD. The focus of this work was to figure out the functional mechanism of PFN1 in macrophage polarization in LUAD. PFN1 expression and its significance in patients' survival were detected by ENCORI and Kaplan-Meier Plotter. RT-qPCR and western blotting examined PFN1 expression in LUAD cells. CCK-8 assay and colony formation assay detected cell proliferation. Flow cytometry detected cell apoptosis. Relevant assay kit tested caspase3 concentration. Western blotting analyzed the expression of proliferation- and apoptosis-related proteins. RT-qPCR and immunofluorescence staining measured M1 and M2 macrophages markers. Mitophagy was assessed by MitoTracker Red staining, immunofluorescence staining, and western blotting. PFN1 expression was increased in LUAD tissues and cells and correlated with the poor survival rate of LUAD patients. Deficiency of PFN1 hindered the proliferation, whereas facilitated the apoptosis of LUAD cells. Additionally, PFN1 interference impaired M2 macrophage polarization. Moreover, PFN1 knockdown exacerbated the mitophagy in LUAD cells and mitophagy inhibitor mitochondrial division inhibitor 1 (Mdivi-1) notably reversed the effects of PFN1 down-regulation on the proliferation, apoptosis as well as macrophage polarization in LUAD cells. To sum up, activation of mitophagy initiated by PFN1 depletion might obstruct the occurrence and M2 macrophage polarization in LUAD.

Kinase-catalyzed biotinylation for discovery and validation of substrates to multispecificity kinases NME1 and NME2

Protein phosphorylation by kinases regulates mammalian cell functions, such as growth, division, and signal transduction. Among human kinases, NME1 and NME2 are associated with metastatic tumor suppression but remain understudied due to the lack of tools to monitor their cellular substrates. In particular, NME1 and NME2 are multispecificity kinases phosphorylating serine, threonine, histidine, and aspartic acid residues of substrate proteins, and the heat and acid sensitivity of phosphohistidine and phosphoaspartate complicates substrate discovery and validation. To provide new substrate monitoring tools, we established the γ-phosphate-modified ATP analog, ATP-biotin, as a cosubstrate for phosphorylbiotinylation of NME1 and NME2 cellular substrates. Building upon this ATP-biotin compatibility, the Kinase-catalyzed Biotinylation with Inactivated Lysates for Discovery of Substrates method enabled validation of a known substrate and the discovery of seven NME1 and three NME2 substrates. Given the paucity of methods to study kinase substrates, ATP-biotin and the Kinase-catalyzed Biotinylation with Inactivated Lysates for Discovery of Substrates method are valuable tools to characterize the roles of NME1 and NME2 in human cell biology.

Protein Profiles and Novel Molecular Biomarkers of Schizophrenia Based on 4D-DIA Proteomics

Schizophrenia is a severe psychological disorder. The current diagnosis mainly relies on clinical symptoms and lacks laboratory evidence, which makes it very difficult to make an accurate diagnosis especially at an early stage. Plasma protein profiles of schizophrenia patients were obtained and compared with healthy controls using 4D-DIA proteomics technology. Furthermore, 79 DEPs were identified between schizophrenia and healthy controls. GO functional analysis indicated that DEPs were predominantly associated with responses to toxic substances and platelet aggregation, suggesting the presence of metabolic and immune dysregulation in patients with schizophrenia. KEGG pathway enrichment analysis revealed that DEPs were primarily enriched in the chemokine signaling pathway and cytokine receptor interactions. A diagnostic model was ultimately established, comprising three proteins, namely, PFN1, GAPDH and ACTBL2. This model demonstrated an AUC value of 0.972, indicating its effectiveness in accurately identifying schizophrenia. PFN1, GAPDH and ACTBL2 exhibit potential as biomarkers for the early detection of schizophrenia. The findings of our studies provide novel insights into the laboratory-based diagnosis of schizophrenia.

Identification of a novel lactylation-related gene signature predicts the prognosis of multiple myeloma and experiment verification

Multiple myeloma (MM) is an incurable hematological malignancy with poor survival. Accumulating evidence reveals that lactylation modification plays a vital role in tumorigenesis. However, research on lactylation-related genes (LRGs) in predicting the prognosis of MM remains limited. Differentially expressed LRGs (DELRGs) between MM and normal samples were investigated from the Gene Expression Omnibus database. Univariate Cox regression and LASSO Cox regression analysis were applied to construct gene signature associated with overall survival. The signature was validated in two external datasets. A nomogram was further constructed and evaluated. Additionally, Enrichment analysis, immune analysis, and drug chemosensitivity analysis between the two groups were investigated. qPCR and immunofluorescence staining were performed to validate the expression and localization of PFN1. CCK-8 and flow cytometry were performed to validate biological function. A total of 9 LRGs (TRIM28, PPIA, SOD1, RRP1B, IARS2, RB1, PFN1, PRCC, and FABP5) were selected to establish the prognostic signature. Kaplan-Meier survival curves showed that high-risk group patients had a remarkably worse prognosis in the training and validation cohorts. A nomogram was constructed based on LRGs signature and clinical characteristics, and showed excellent predictive power by calibration curve and C-index. Moreover, biological pathways, immunologic status, as well as sensitivity to chemotherapy drugs were different between high- and low-risk groups. Additionally, the hub gene PFN1 is highly expressed in MM, knocking down PFN1 induces cell cycle arrest, suppresses cell proliferation and promotes cell apoptosis. In conclusion, our study revealed that LRGs signature is a promising biomarker for MM that can effectively early distinguish high-risk patients and predict prognosis.

The Roles of RhoA/ROCK/NF-κB Pathway in Microglia Polarization Following Ischemic Stroke

Ischemic stroke is the leading cause of death and disability worldwide. Nevertheless, there still lacks the effective therapies for ischemic stroke. Microglia are resident macrophages of the central nervous system (CNS) and can initiate immune responses and monitor the microenvironment. Microglia are activated and polarize into proinflammatory or anti‑inflammatory phenotype in response to various brain injuries, including ischemic stroke. Proinflammatory microglia could generate immunomodulatory mediators, containing cytokines and chemokines, these mediators are closely associated with secondary brain damage following ischemic stroke. On the contrary, anti-inflammatory microglia facilitate recovery following stroke. Regulating the activation and the function of microglia is crucial in exploring the novel treatments for ischemic stroke patients. Accumulating studies have revealed that RhoA/ROCK pathway and NF-κB are famous modulators in the process of microglia activation and polarization. Inhibiting these key modulators can promote the polarization of microglia to anti-inflammatory phenotype. In this review, we aimed to provide a comprehensive overview on the role of RhoA/ROCK pathway and NF-κB in the microglia activation and polarization, reveal the relationship between RhoA/ROCK pathway and NF-κB in the pathological process of ischemic stroke. In addition, we likewise discussed the drug modulators targeting microglia polarization.

FgPfn participates in vegetative growth, sexual reproduction, pathogenicity, and fungicides sensitivity via affecting both microtubules and actin in the filamentous fungus Fusarium graminearum

Fusarium head blight (FHB), caused by Fusarium graminearum species complexes (FGSG), is an epidemic disease in wheat and poses a serious threat to wheat production and security worldwide. Profilins are a class of actin-binding proteins that participate in actin depolymerization. However, the roles of profilins in plant fungal pathogens remain largely unexplored. Here, we identified FgPfn, a homolog to profilins in F. graminearum, and the deletion of FgPfn resulted in severe defects in mycelial growth, conidia production, and pathogenicity, accompanied by marked disruptions in toxisomes formation and deoxynivalenol (DON) transport, while sexual development was aborted. Additionally, FgPfn interacted with Fgα1 and Fgβ2, the significant components of microtubules. The organization of microtubules in the ΔFgPfn was strongly inhibited under the treatment of 0.4 μg/mL carbendazim, a well-known group of tubulin interferers, resulting in increased sensitivity to carbendazim. Moreover, FgPfn interacted with both myosin-5 (FgMyo5) and actin (FgAct), the targets of the fungicide phenamacril, and these interactions were reduced after phenamacril treatment. The deletion of FgPfn disrupted the normal organization of FgMyo5 and FgAct cytoskeleton, weakened the interaction between FgMyo5 and FgAct, and resulting in increased sensitivity to phenamacril. The core region of the interaction between FgPfn and FgAct was investigated, revealing that the integrity of both proteins was necessary for their interaction. Furthermore, mutations in R72, R77, R86, G91, I101, A112, G113, and D124 caused the non-interaction between FgPfn and FgAct. The R86K, I101E, and D124E mutants in FgPfn resulted in severe defects in actin organization, development, and pathogenicity. Taken together, this study revealed the role of FgPfn-dependent cytoskeleton in development, DON production and transport, fungicides sensitivity in F. graminearum.

Comprehensive Assessment of Ischemic Stroke in Nonhuman Primates: Neuroimaging, Behavioral, and Serum Proteomic Analysis

Ischemic strokes, prevalence and impactful, underscore the necessity of advanced research models closely resembling human physiology. Our study utilizes nonhuman primates (NHPs) to provide a detailed exploration of ischemic stroke, integrating neuroimaging data, behavioral outcomes, and serum proteomics to elucidate the complex interplay of factors involved in stroke pathophysiology. We observed a consistent pattern in infarct volume, peaking at 1-month postmiddle cerebral artery occlusion (MCAO) and then stabilized. This pattern was strongly correlated to notable changes in motor function and working memory performance. Using diffusion tensor imaging (DTI), we detected significant alterations in fractional anisotropy (FA) and mean diffusivity (MD) values, signaling microstructural changes in the brain. These alterations closely correlated with the neurological and cognitive deficits that we observed, highlighting the sensitivity of DTI metrics in stroke assessment. Behaviorally, the monkeys exhibited a reliance on their unaffected limb for compensatory movements, a common response to stroke impairment. This adaptation, along with consistent DTI findings, suggests a significant impact of stroke on motor function and spatial perception. Proteomic analysis through MS/MS functional enrichment identified two distinct groups of proteins with significant changes post-MCAO. Notably, MMP9, THBS1, MB, PFN1, and YWHAZ were identified as potential biomarkers and therapeutic targets for ischemic stroke. Our results underscore the complex nature of stroke and advocate for an integrated approach, combining neuroimaging, behavioral studies, and proteomics, for advancing our understanding and treatment of this condition.

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.

Development and Validation of Serum Markers as Noninvasive Diagnostic Methods for Achalasia

INTRODUCTION

Currently, the diagnosis of achalasia mainly relies on invasive or radioactive examinations. This study aimed to develop a noninvasive diagnostic method for achalasia based on specific serum markers.

METHODS

Serum levels of profilin-1, galectin-10, immunoglobulin heavy variable 3-9, vasodilator-stimulated phosphoprotein, and transgelin-2 were measured in patients with achalasia and controls by enzyme-linked immunosorbent assay. The diagnostic values and thresholds were determined by the receiver operating characteristic curve analysis. Then, patients with dysphagia were prospectively enrolled to validate the ability of these molecules for achalasia diagnosing.

RESULTS

A total of 142 patients with achalasia and 50 nonachalasia controls (healthy volunteers and patients with reflux esophagitis) were retrospectively included. The serum levels of profilin-1, galectin-10, and transgelin-2 in patients with achalasia were significantly higher than those in healthy volunteers and patients with reflux esophagitis ( P all < 0.001). Profilin-1, galectin-10, and transgelin-2 were of good performance in diagnosing achalasia, with optimal thresholds of 2,171.2, 33.9, and 1,630.6 pg/mL, respectively. Second, 40 patients with dysphagia were prospectively enrolled to the validation of achalasia. For profilin-1, the positive predictive value, negative predictive value, sensitivity, and specificity were 100.0%, 64.5%, 45.0%, and 100.0%, respectively. The figures for transgelin-2 were 65.5%, 90.9%, 95.0%, and 50.0%. When both increased, the positive predictive value reached to 100.0%. When both indexes were normal, the negative predictive value was 100.0%.

DISCUSSION

Profilin-1 and transgelin-2 were promising biomarkers for achalasia diagnosis and performed better in combination. Further multicenter studies are necessary to verify their application as preliminary screening tools for achalasia.

The loss of profilin1 is catastrophic to podocytes

Profilin1 belongs to a family of small monomeric actin-binding proteins with diverse roles in fundamental actin-dependent cellular processes required for cell survival. Podocytes are postmitotic visceral epithelial cells critical for the structure and function of the kidney filtration barrier. There is emerging evidence that the actin-related mode of cell death known as mitotic catastrophe is an important pathway involved in podocyte loss. In this issue of the JCI, Tian, Pedigo, and colleagues demonstrate that profilin1 deficiency in podocytes triggered cell cycle reentry, resulting in abortive cytokinesis with a loss in ribosomal RNA processing that leads to podocyte loss and glomerulosclerosis. This study demonstrates the essential role of actin dynamics in mediating this fundamental mode of podocyte cell death.

Profilin1 is required for prevention of mitotic catastrophe in murine and human glomerular diseases

The progression of proteinuric kidney diseases is associated with podocyte loss, but the mechanisms underlying this process remain unclear. Podocytes reenter the cell cycle to repair double-stranded DNA breaks. However, unsuccessful repair can result in podocytes crossing the G1/S checkpoint and undergoing abortive cytokinesis. In this study, we identified Pfn1 as indispensable in maintaining glomerular integrity - its tissue-specific loss in mouse podocytes resulted in severe proteinuria and kidney failure. Our results suggest that this phenotype is due to podocyte mitotic catastrophe (MC), characterized histologically and ultrastructurally by abundant multinucleated cells, irregular nuclei, and mitotic spindles. Podocyte cell cycle reentry was identified using FUCCI2aR mice, and we observed altered expression of cell-cycle associated proteins, such as p21, p53, cyclin B1, and cyclin D1. Podocyte-specific translating ribosome affinity purification and RNA-Seq revealed the downregulation of ribosomal RNA-processing 8 (Rrp8). Overexpression of Rrp8 in Pfn1-KO podocytes partially rescued the phenotype in vitro. Clinical and ultrastructural tomographic analysis of patients with diverse proteinuric kidney diseases further validated the presence of MC podocytes and reduction in podocyte PFN1 expression within kidney tissues. These results suggest that profilin1 is essential in regulating the podocyte cell cycle and its disruption leads to MC and subsequent podocyte loss.

Adverse developmental impacts in progeny of zebrafish exposed to the agricultural herbicide atrazine during embryogenesis

Atrazine (ATZ) is an herbicide commonly used on crops in the Midwestern US and other select global regions. The US Environmental Protection Agency ATZ regulatory limit is 3 parts per billion (ppb; µg/L), but this limit is often exceeded. ATZ has a long half-life, is a common contaminant of drinking water sources, and is indicated as an endocrine disrupting chemical in multiple species. The zebrafish was used to test the hypothesis that an embryonic parental ATZ exposure alters protein levels leading to modifications in morphology and behavior in developing progeny. Zebrafish embryos (F1) were collected from adults (F0) exposed to 0, 0.3, 3, or 30 ppb ATZ during embryogenesis. Differential proteomics, morphology, and behavior assays were completed with offspring aged 120 or 144 h with no additional chemical treatment. Proteomic analysis identified differential expression of proteins associated with neurological development and disease; and organ and organismal morphology, development, and injury, specifically the skeletomuscular system. Head length and ratio of head length to total length was significantly increased in the F1 of 0.3 and 30 ppb ATZ groups (p < 0.05). Based on molecular pathway alterations, further craniofacial morphology assessment found decreased distance for cartilaginous structures, decreased surface area and distance between saccular otoliths, and a more posteriorly positioned notochord (p < 0.05), indicating delayed ossification and skeletal growth. The visual motor response assay showed hyperactivity in progeny of the 30 ppb treatment group for distance moved and of the 0.3 and 30 ppb treatment groups for time spent moving (p < 0.05). Due to the changes in saccular otoliths, an acoustic startle assay was completed and showed decreased response in the 0.3 and 30 ppb treatments (p < 0.05). These findings suggest that a single embryonic parental exposure alters cellular pathways in their progeny that lead to perturbations in craniofacial development and behavior.

Rosuvastatin effects on the HDL proteome in hyperlipidemic patients

The advancements in proteomics have provided a better understanding of the functionality of apolipoproteins and lipoprotein-associated proteins, with the HDL lipoprotein fraction being the most studied. The focus of this study was to evaluate the HDL proteome in dyslipidemic subjects without an established cardiovascular disease, as well as to test whether rosuvastatin treatment alters the HDL proteome. Patients with primary hypercholesterolemia or mixed dyslipidemia were assigned to 20 mg/day rosuvastatin and blood samples were drawn at study entry and after 12 weeks of treatment. A label-free LC-MS/MS protein profiling was conducted, coupled with bioinformatics analysis. Sixty-nine HDL proteins were identified, belonging to four main biological function clusters: lipid transport and metabolism; platelet activation, degranulation, and aggregation, wound response and wound healing; immune response; inflammatory and acute phase response. Five HDL proteins showed statistically significant differences in the abundance (Anova ≤ 0.05), before and after rosuvastatin treatment. Platelet factor 4 variant (PF4V1), Pregnancy-specific beta-1-glycoprotein 2 (PSG2), Profilin-1 (PFN1) and Keratin type II cytoskeletal 2 epidermal (KRT2) showed decreased expressions, while Integrin alpha-IIb (ITGA2B) showed an increased expression after treatment with rosuvastatin. The ELISA validation of PFN1 segregated the subjects into responders and non-responders, as PFN1 levels after rosuvastatin were shown to mostly depend on the subjects' inflammatory phenotype. Findings from this study introduce novel insights into the HDL proteome and statin pleiotropism.

The role of RhoA/ROCK pathway in the ischemic stroke-induced neuroinflammation

It is widely known that ischemic stroke is the prominent cause of death and disability. To date, neuroinflammation following ischemic stroke represents a complex event, which is an essential process and affects the prognosis of both experimental stroke animals and stroke patients. Intense neuroinflammation occurring during the acute phase of stroke contributes to neuronal injury, BBB breakdown, and worse neurological outcomes. Inhibition of neuroinflammation may be a promising target in the development of new therapeutic strategies. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of RhoA/ROCK pathway possesses important roles in promoting the neuroinflammation and mediating brain injury. In addition, nuclear factor-kappa B (NF-κB) is another vital regulator of ischemic stroke-induced neuroinflammation through regulating the functions of microglial cells and astrocytes. After stroke onset, the microglial cells and astrocytes are activated and undergo the morphological and functional changes, thereby deeply participate in a complicated neuroinflammation cascade. In this review, we focused on the relationship among RhoA/ROCK pathway, NF-κB and glial cells in the neuroinflammation following ischemic stroke to reveal new strategies for preventing the intense neuroinflammation.

Serum proteomic identification and validation of two novel atherosclerotic aortic aneurysm biomarkers, profilin 1 and complement factor D

BACKGROUND

Effective diagnostic biomarkers for aortic aneurysm (AA) that are detectable in blood tests are required because early detection and rupture risk assessment of AA can provide insights into medical therapy and preventive treatments. However, known biomarkers for AA lack specificity and reliability for clinical diagnosis.

METHODS

We performed proteome analysis of serum samples from patients with atherosclerotic thoracic AA (TAA) and healthy control (HC) subjects to identify diagnostic biomarkers for AA. Serum samples were separated into low-density lipoprotein, high-density lipoprotein, and protein fractions, and the major proteins were depleted. From the proteins identified in the three fractions, we narrowed down biomarker candidates to proteins uniformly altered in all fractions between patients with TAA and HC subjects and evaluated their capability to discriminate patients with TAA and those with abdominal AA (AAA) from HC subjects using receiver operating characteristic (ROC) analysis. For the clinical validation, serum concentrations of biomarker candidates were measured in patients with TAA and AAA registered in the biobank of the same institute, and their capability for the diagnosis was evaluated.

RESULTS

Profilin 1 (PFN1) and complement factor D (CFD) showed the most contrasting profiles in all three fractions between patients with TAA and HC subjects and were selected as biomarker candidates. The PFN1 concentration decreased, whereas the CFD concentration increased in the sera of patients with TAA and AAA when compared with those of HC subjects. The ROC analysis showed that these proteins could discriminate patients with TAA and AAA from HC subjects. In the validation study, these candidates showed significant concentration differences between patients with TAA or AAA and controls. PFN1 and CFD showed sufficient area under the curve (AUC) in the ROC analysis, and their combination further increased the AUC. The serum concentrations of PFN1 and CFD also showed significant differences between patients with aortic dissection and controls in the validation study.

CONCLUSION

PFN1 and CFD are potential diagnostic biomarkers for TAA and AAA and measurable in blood samples; their diagnostic performance can be augmented by their combination. These biomarkers may facilitate the development of diagnostic systems to identify patients with AA.

The identification of high-performing antibodies for Profilin-1 for use in Western blot, immunoprecipitation and immunofluorescence

Profilin-1, a member of the Profilin family, is a ubiquitously expressed protein that controls actin polymerization in a concentration-dependent manner. As mutations in the Profilin-1 gene have potential implications in neurodegenerative disease progression, well-characterized anti-Profilin-1 antibodies would be beneficial to the scientific community. In this study, we characterized sixteen Profilin-1 commercial antibodies for Western blot, immunoprecipitation, and immunofluorescence applications, using a standardized experimental protocol based on comparing read-outs in knockout cell lines and isogenic parental controls. We identified many high-performing antibodies and encourage readers to use this report as a guide to select the most appropriate antibody for their specific needs.

In silico analysis of TUBA4A mutations in Amyotrophic Lateral Sclerosis to define mechanisms of microtubule disintegration

Amyotrophic lateral sclerosis (ALS) is an inexorably progressive and degenerative disorder of motor neurons with no currently-known cure. Studies to determine the mechanism of neurotoxicity and the impact of ALS-linked mutations (SOD1, FUS, TARDP, C9ORF72, PFN1, TUBA4A and others) have greatly expanded our knowledge of ALS disease mechanisms and have helped to identify potential targets for ALS therapy. Cellular pathologies (e.g., aggregation of mutant forms of SOD1, TDP43, FUS, Ubiqulin2, PFN1, and C9ORF72), mitochondrial dysfunction, neuroinflammation, and oxidative damage are major pathways implicated in ALS. Nevertheless, the selective vulnerability of motor neurons remains unexplained. The importance of tubulins for long-axon infrastructure, and the special morphology and function of motor neurons, underscore the central role of the cytoskeleton. The recent linkage of mutations to the tubulin α chain, TUBA4A, to familial and sporadic cases of ALS provides a new investigative opportunity to shed light on both mechanisms of ALS and the vulnerability of motor neurons. In the current study we investigate TUBA4A, a structural microtubule protein with mutations causal to familial ALS, using molecular-dynamic (MD) modeling of protein structure to predict the effects of each mutation and its overall impact on GTP binding, chain stability, tubulin assembly, and aggregation propensity. These studies predict that each of the reported mutations will cause notable structural changes to the TUBA4A (α chain) tertiary protein structure, adversely affecting its physical properties and functions. Molecular docking and MD simulations indicate certain α chain mutations (e.g. K430N, R215C, and W407X) may cause structural deviations that impair GTP binding, and plausibly prevent or destabilize tubulin polymerization. Furthermore, several mutations (including R320C and K430N) confer a significant increase in predicted aggregation propensity of TUBA4A mutants relative to wild-type. Taken together, these in silico modeling studies predict structural perturbations and disruption of GTP binding, culminating in failure to form a stable tubulin heterocomplex, which may furnish an important pathogenic mechanism to trigger motor neuron degeneration in ALS.

Comparison between PFN1 and SOD1 mutations in amyotrophic lateral sclerosis

BACKGROUND

The objective of this study was to characterize the prototypical phenotype of patients with amyotrophic lateral sclerosis (ALS) associated with PFN1 mutations in profilin 1 (PFN1) and to determine clinical indications to test for mutations in this gene.

MATERIAL AND METHODS

The phenotype of three relatives carrying the M114V PFN1 mutation are detailed here and are compared with those of patients with ALS linked to PFN1 previously reported in the literature.

RESULTS

In this pedigree and in the literature, the main clinical findings which best describe familial ALS linked to PFN1 might be the following characteristics: pedigrees over five cases, age of onset around 50 years, site of onset systematically lower limbs and the absence of cognitive impairment.

CONCLUSION

First, the infrequent incidence of patients with ALS linked to PFN1 mutation supports the pursuit of a precise characterization of the phenotype linked to PFN1 mutations. Then, the numerous similarities between the phenotype amongst patients linked to SOD1 and PFN1 mutations and between histological features amongst both mice models prompts a review of the current ALS classifications, taking into consideration both phenotype and genotype.

Update on the pathogenesis and genetics of Paget’s disease of bone

Studies over the past two decades have led to major advances in the pathogenesis of Paget’s disease of bone (PDB) and particularly on the role of genetic factors. Germline mutations of different genes have been identified, as a possible cause of this disorder, and most of the underlying pathways are implicated in the regulation of osteoclast differentiation and function, whereas other are involved in cell autophagy mechanisms. In particular, about 30 different germline mutations of the Sequestosome 1 gene (SQSTM1) have been described in a significant proportion of familial and sporadic PDB cases. The majority of SQSTM1 mutations affect the ubiquitin-binding domain of the protein and are associated to a more severe clinical expression of the disease. Also, germline mutations in the ZNF687 and PFN1 genes have been associated to severe, early onset, polyostotic PDB with increased susceptibly to neoplastic degeneration, particularly giant cell tumor. Mutations in the VCP (Valosin Containing Protein) gene cause the autosomal dominant syndrome “Inclusion Body Myopathy, PDB, Fronto-temporal Dementia,” characterized by pagetic manifestations, associated with myopathy, amyotrophic lateral sclerosis and fronto-temporal dementia. Moreover, germline mutations in the TNFRSF11A gene, which encodes for RANK, were associated with rare syndromes showing some histopathological, radiological, and clinical overlap with PDB and in two cases of early onset PDB-like disease. Likewise, genome wide association studies performed in unrelated PDB cases identified other potential predisposition genes and/or susceptibility loci. Thus, it is likely that polygenic factors are involved in the PDB pathogenesis in many individuals and that modifying genes may contribute in refining the clinical phenotype. Moreover, the contribution of somatic mutations of SQSTM1 gene and/or epigenetic mechanisms in the pathogenesis of skeletal pagetic abnormalities and eventually neoplastic degeneration, cannot be excluded. Indeed, clinical and experimental observations indicate that genetic susceptibility might not be a sufficient condition for the clinical development of PDB without the concomitant intervention of viral infection, in primis paramixoviruses, and/or other environmental factors (e.g., pesticides, heavy metals or tobacco exposure), at least in a subset of cases. This review summarizes the most important advances that have been made in the field of cellular and molecular biology PDB over the past decades.

RNA as a source of biomarkers for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, leads to the loss of motor neurons. There are currently no effective therapies to treat this disease as the molecular mechanisms of motor neuron degeneration are largely unknown. The diagnosis of ALS, or motor neuron disease, is not a simple process that can be carried out with one doctor visit or a single simple test. This has created a major problem for patients with ALS and their physicians since they are often not diagnosed until about a year into the disease. In order to combat this issue, new techniques of detecting the clinical and pathological changes of the disease are critical. These techniques are currently being studied and developed which can revolutionize the diagnosis of ALS. Once this technology is established, it may have application to monitor the progression of the disease. RNA-Seq is a powerful tool that has potential to identify RNA as small molecules in patients' biological samples (Plasma, Cerebral Spinal Fluid) which can be used to inform the system changes in patients with ALS. In this review, we will explore and discuss our current work on RNA-Seq and its development of biomarkers to diagnose and assess the rate of progression in the disease.

Histidine tautomerism dependent conformational transitions driven aggregation of profilin-1: Implications in amyotrophic lateral sclerosis

Aggregation of profilin-1 (PFN1) causes a fatal neurodegenerative disease, familial amyotrophic lateral sclerosis (fALS). Histidine (His) tautomerism has been linked to the formation of fibril aggregation causing neurodegenerative disease. Characterization of intermediate species that form during aggregation is crucial, however, this has proven very challenging for experimentalists due to their transient nature. Hence, molecular dynamics (MD) simulations have been performed on the His tautomeric isomers εε, εδ, δε, and δδ of PFN1 to explain the structural changes and to correlate them with its aggregation propensity. MD simulations show that His133 presumably plays a major role in the aggregation of PFN1 upon His tautomerism compared to His119. Further, the formation of a new 3₁₀-helix is observed in εε and δε but 3₁₀-helix is not observed in δδ and εδ isomers. In addition, our findings unveil that β-sheet dominating conformations are observed in His119(δ)-His133(δ) δδ isomer of PFN1 with significant antiparallel β-sheets between residues T15-G23, S29-A33, L63-L65, Q68-S76, F83-T89, T97-T105, and K107-K115, suggesting a novel aggregation mechanism possibly occur for the formation of PFN1 aggregates. Overall, these results propose that MD simulations of PFN1 His tautomers can provide a detailed microscopic understanding of the aggregation mechanisms which are hard to probe through experiments.

Profilin 1 Induces Tumor Metastasis by Promoting Microvesicle Secretion Through the ROCK 1/p-MLC Pathway in Non-Small Cell Lung Cancer

Profilin 1 (PFN1), an actin-binding protein, plays contrasting roles in the metastasis of several cancers; however, its role in non-small cell lung cancer (NSCLC) metastasis remains unclear. Here, PFN1 expression was upregulated in metastatic NSCLC tissues. PFN1 overexpression significantly promotes NSCLC metastasis in vitro and in vivo. Proteomics analysis revealed PFN1 involvment in microvesicles (MVs) secretion. In vitro experiments confirmed that PFN1 overexpression increased secretion of MVs. MVs are important mediators of metastasis. Here, we show an increased abundance of MVs in the sera of patients with metastatic NSCLC compared to that in the sera of patients with non-metastatic NSCLC. Both in vitro and in vivo experiments revealed that PFN1 could increase MV secretion, and MVs derived from PFN1-overexpressing cells markedly promoted NSCLC metastasis. We then elucidated the mechanisms underlying PFN1-mediated regulation of MVs and found that PFN1 could interact with ROCK1 and enhance its kinase activity to promote myosin light chain (MLC) phosphorylation for MV secretion. Inhibition of ROCK1 decreased MV secretion and partially reversed the PFN1-induced promotion of NSCLC metastasis. Collectively, these findings show that PFN1 regulates MV secretion to promote NSCLC metastasis. PFN1 and MVs represent potential predictors or therapeutic targets for NSCLC metastasis.

Application of molecular dynamics simulation in biomedicine

Molecular dynamics (MD) simulation has been widely used in the field of biomedicine to study the conformational transition of proteins caused by mutation or ligand binding/unbinding. It provides some perspectives those are difficult to find in traditional biochemical or pathological experiments, for example, detailed effects of mutations on protein structure and protein-protein/ligand interaction at the atomic level. In this review, a broad overview on conformation changes and drug discovery by MD simulation is given. We first discuss the preparation of protein structure for MD simulation, which is a key step that determines the accuracy of the simulation. Then, we summarize the applications of commonly used force fields and MD simulations in scientific research. Finally, enhanced sampling methods and common applications of these methods are introduced. In brief, MD simulation is a powerful tool and it can be used to guide experimental study. The combination of MD simulation and experimental techniques is an a priori means to solve the biomedical problems and give a deep understanding on the relationship between protein structure and function.

Protein Network Analysis Reveals a Functional Connectivity of Dysregulated Processes in ALS and SMA

Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) are neurodegenerative diseases which are characterized by the loss of motoneurons within the central nervous system. SMA is a monogenic disease caused by reduced levels of the Survival of motoneuron protein, whereas ALS is a multi-genic disease with over 50 identified disease-causing genes and involvement of environmental risk factors. Although these diseases have different causes, they partially share identical phenotypes and pathomechanisms. To analyze and identify functional connections and to get a global overview of altered pathways in both diseases, protein network analyses are commonly used. Here, we used an in silico tool to test for functional associations between proteins that are involved in actin cytoskeleton dynamics, fatty acid metabolism, skeletal muscle metabolism, stress granule dynamics as well as SMA or ALS risk factors, respectively. In network biology, interactions are represented by edges which connect proteins (nodes). Our approach showed that only a few edges are necessary to present a complex protein network of different biological processes. Moreover, Superoxide dismutase 1, which is mutated in ALS, and the actin-binding protein profilin1 play a central role in the connectivity of the aforementioned pathways. Our network indicates functional links between altered processes that are described in either ALS or SMA. These links may not have been considered in the past but represent putative targets to restore altered processes and reveal overlapping pathomechanisms in both diseases.

Modelling amyotrophic lateral sclerosis in rodents

The efficient study of human disease requires the proper tools, one of the most crucial of which is an accurate animal model that faithfully recapitulates the human condition. The study of amyotrophic lateral sclerosis (ALS) is no exception. Although the majority of ALS cases are considered sporadic, most animal models of this disease rely on genetic mutations identified in familial cases. Over the past decade, the number of genes associated with ALS has risen dramatically and, with each new genetic variant, there is a drive to develop associated animal models. Rodent models are of particular importance as they allow for the study of ALS in the context of a living mammal with a comparable CNS. Such models not only help to verify the pathogenicity of novel mutations but also provide critical insight into disease mechanisms and are crucial for the testing of new therapeutics. In this Review, we aim to summarize the full spectrum of ALS rodent models developed to date.

Biochemical characterization of actin assembly mechanisms with ALS-associated profilin variants

Eight separate mutations in the actin-binding protein profilin-1 have been identified as a rare cause of amyotrophic lateral sclerosis (ALS). Profilin is essential for many neuronal cell processes through its regulation of lipids, nuclear signals, and cytoskeletal dynamics, including actin filament assembly. Direct interactions between profilin and actin monomers inhibit actin filament polymerization. In contrast, profilin can also stimulate polymerization by simultaneously binding actin monomers and proline-rich tracts found in other proteins. Whether the ALS-associated mutations in profilin compromise these actin assembly functions is unclear. We performed a quantitative biochemical comparison of the direct and formin mediated impact for the eight ALS-associated profilin variants on actin assembly using classic protein-binding and single-filament microscopy assays. We determined that the binding constant of each profilin for actin monomers generally correlates with the actin nucleation strength associated with each ALS-related profilin. In the presence of formin, the A20T, R136W, Q139L, and C71G variants failed to activate the elongation phase of actin assembly. This diverse range of formin-activities is not fully explained through profilin-poly-L-proline (PLP) interactions, as all ALS-associated variants bind a formin-derived PLP peptide with similar affinities. However, chemical denaturation experiments suggest that the folding stability of these profilins impact some of these effects on actin assembly. Thus, changes in profilin protein stability and alterations in actin filament polymerization may both contribute to the profilin-mediated actin disruptions in ALS.

Detection of structural and conformational changes in ALS-causing mutant profilin-1 with hydrogen/deuterium exchange mass spectrometry and bioinformatics techniques

The hydrogen/deuterium exchange (HDX) is a reliable method to survey the dynamic behavior of proteins and epitope mapping. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is a quantifying tool to assay for HDX in the protein of interest. We combined HDX-MALDI-TOF MS and molecular docking/MD simulation to identify accessible amino acids and analyze their contribution into the structural changes of profilin-1 (PFN-1). The molecular docking/MD simulations are computational tools for enabling the analysis of the type of amino acids that may be involved via HDX identified under the lowest binding energy condition. Glycine to valine amino acid (G117V) substitution mutation is linked to amyotrophic lateral sclerosis (ALS). This mutation is found to be in the actin-binding site of PFN-1 and prevents the dimerization/polymerization of actin and invokes a pathologic toxicity that leads to ALS. In this study, we sought to understand the PFN-1 protein dynamic behavior using purified wild type and mutant PFN-1 proteins. The data obtained from HDX-MALDI-TOF MS for PFN-1^WT and PFN-1^G117V at various time intervals, from seconds to hours, revealed multiple peaks corresponding to molecular weights from monomers to multimers. PFN-1/Benzaldehyde complexes identified 20 accessible amino acids to HDX that participate in the docking simulation in the surface of WT and mutant PFN-1. Consistent results from HDX-MALDI-TOF MS and docking simulation predict candidate amino acid(s) involved in the dimerization/polymerization of PFN^G117V. This information may shed critical light on the structural and conformational changes with details of amino acid epitopes for mutant PFN-1s' dimerization, oligomerization, and aggregation.

Profilin-1 is involved in macroangiopathy induced by advanced glycation end products via vascular remodeling and inflammation

BACKGROUND

The accumulation of advanced glycation end products (AGEs) have been implicated in the development and progression of diabetic vasculopathy. However, the role of profilin-1 as a multifunctional actin-binding protein in AGEs-induced atherosclerosis (AS) is largely unknown.

AIM

To explore the potential role of profilin-1 in the pathogenesis of AS induced by AGEs, particularly in relation to the Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) signaling pathway.

METHODS

Eighty-nine individuals undergoing coronary angiography were enrolled in the study. Plasma cytokine levels were detected using ELISA kits. Rat aortic vascular smooth muscle cells (RASMCs) were incubated with different compounds for different times. Cell proliferation was determined by performing the MTT assay and EdU staining. An AGEs-induced vascular remodeling model was established in rats and histological and immunohistochemical analyses were performed. The mRNA and protein levels were detected using real-time PCR and Western blot analysis, respectively. In vivo, shRNA transfection was performed to verify the role of profilin-1 in AGEs-induced proatherogenic mediator release and aortic remodeling. Statistical analyses were performed using SPSS 22.0 software.

RESULTS

Compared with the control group, plasma levels of profilin-1 and receptor for AGEs (RAGE) were significantly increased in patients with coronary artery disease, especially in those complicated with diabetes mellitus (P < 0.01). The levels of profilin-1 were positively correlated with the levels of RAGE (P < 0.01); additionally, the levels of both molecules were positively associated with the degree of coronary artery stenosis (P < 0.01). In vivo, tail vein injections of AGEs induced the release of proatherogenic mediators, such as asymmetric dimethylarginine, intercellular adhesion molecule-1, and the N-terminus of procollagen III peptide, concomitant with apparent aortic morphological changes and significantly upregulated expression of the profilin-1 mRNA and protein in the thoracic aorta (P < 0.05 or P < 0.01). Downregulation of profilin-1 expression with an shRNA significantly attenuated AGEs-induced proatherogenic mediator release (P < 0.05) and aortic remodeling. In vitro, incubation of vascular smooth muscle cells (VSMCs) with AGEs significantly promoted cell proliferation and upregulated the expression of the profilin-1 mRNA and protein (P < 0.05). AGEs (200 μg/mL, 24 h) significantly upregulated the expression of the STAT3 mRNA and protein and JAK2 protein, which was blocked by a JAK2 inhibitor (T3042-1) and/or STAT3 inhibitor (T6308-1) (P < 0.05). In addition, pretreatment with T3042-1 or T6308-1 significantly inhibited AGEs-induced RASMC proliferation (P < 0.05).

CONCLUSION

AGEs induce proatherogenic events such as VSMC proliferation, proatherogenic mediator release, and vascular remodeling, changes that can be attenuated by silencing profilin-1 expression. These results suggest a crucial role for profilin-1 in AGEs-induced vasculopathy.

Nearly 30 Years of Animal Models to Study Amyotrophic Lateral Sclerosis: A Historical Overview and Future Perspectives

Amyotrophic lateral sclerosis (ALS) is a fatal, multigenic, multifactorial, and non-cell autonomous neurodegenerative disease characterized by upper and lower motor neuron loss. Several genetic mutations lead to ALS development and many emerging gene mutations have been discovered in recent years. Over the decades since 1990, several animal models have been generated to study ALS pathology including both vertebrates and invertebrates such as yeast, worms, flies, zebrafish, mice, rats, guinea pigs, dogs, and non-human primates. Although these models show different peculiarities, they are all useful and complementary to dissect the pathological mechanisms at the basis of motor neuron degeneration and ALS progression, thus contributing to the development of new promising therapeutics. In this review, we describe the up to date and available ALS genetic animal models, classified by the different genetic mutations and divided per species, pointing out their features in modeling, the onset and progression of the pathology, as well as their specific pathological hallmarks. Moreover, we highlight similarities, differences, advantages, and limitations, aimed at helping the researcher to select the most appropriate experimental animal model, when designing a preclinical ALS study.

Effect of profilin-1 on the asymmetric dimethylarginine-induced vascular lesion-associated hypertension

Previous studies have demonstrated that the levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, are strongly associated with hypertension, diabetes, and cardiovascular diseases. Profilin-1, an actin-binding protein, has been documented to be involved in endothelial injury and in the proliferation of vascular smooth muscle cells resulting from hypertension. However, the role of profilin-1 in ADMA-induced vascular injury in hypertension remains largely unknown. Forty healthy subjects and forty-two matched patients with essential hypertension were enrolled, and the related indexes of vascular injury in plasma were detected. Rat aortic smooth muscle cells (RASMCs) were treated with different concentrations of ADMA for different periods of time and transfected with profilin-1 small hairpin RNA to interrupt the expression of profilin-1. To determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway, RASMCs were pretreated with AG490 or rapamycin. The expression of profilin-1 was tested using real-time polymerase chain reaction (PCR) and western blot analysis. Cell proliferation was measured by flow cytometry and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazoliumbromide assays. Compared with healthy subjects, the levels of ADMA and profilin-1 were markedly elevated in hypertensive individuals, while the levels of NO were significantly decreased (p < 0.05). In vitro, studies showed ADMA-induced profilin-1 expression in a concentration- and time-dependent manner in RASMCs (p < 0.05), concomitantly with promoting the proliferation of RASMCs. Furthermore, ADMA-mediated proliferation of RASMCs and upregulation expression of profilin-1 were inhibited by blockade of the JAK2/STAT3 pathway or knockdown of profilin-1. Profilin-1 implicated in the ADMA-mediated vascular lesions in hypertension.

Hecw controls oogenesis and neuronal homeostasis by promoting the liquid state of ribonucleoprotein particles

Specialised ribonucleoprotein (RNP) granules are a hallmark of polarized cells, like neurons and germ cells. Among their main functions is the spatial and temporal modulation of the activity of specific mRNA transcripts that allow specification of primary embryonic axes. While RNPs composition and role are well established, their regulation is poorly defined. Here, we demonstrate that Hecw, a newly identified Drosophila ubiquitin ligase, is a key modulator of RNPs in oogenesis and neurons. Hecw depletion leads to the formation of enlarged granules that transition from a liquid to a gel-like state. Loss of Hecw activity results in defective oogenesis, premature aging and climbing defects associated with neuronal loss. At the molecular level, reduced ubiquitination of the Fmrp impairs its translational repressor activity, resulting in altered Orb expression in nurse cells and Profilin in neurons.

Ribonucleoprotein (RNP) granules are responsible for mRNA transport and local translation required for neuronal and oocyte maturation. Here the authors show that loss of the Drosophila Ub ligase Hecw enlarges RNP granules, leads to a liquid to gel-like transition, and results in defective oogenesis and neuronal loss.

Profilin Isoforms in Health and Disease - All the Same but Different

Profilins are small actin binding proteins, which are structurally conserved throughout evolution. They are probably best known to promote and direct actin polymerization. However, they also participate in numerous cell biological processes beyond the roles typically ascribed to the actin cytoskeleton. Moreover, most complex organisms express several profilin isoforms. Their cellular functions are far from being understood, whereas a growing number of publications indicate that profilin isoforms are involved in the pathogenesis of various diseases. In this review, we will provide an overview of the profilin family and "typical" profilin properties including the control of actin dynamics. We will then discuss the profilin isoforms of higher animals in detail. In terms of cellular functions, we will focus on the role of Profilin 1 (PFN1) and Profilin 2a (PFN2a), which are co-expressed in the central nervous system. Finally, we will discuss recent findings that link PFN1 and PFN2a to neurological diseases, such as amyotrophic lateral sclerosis (ALS), Fragile X syndrome (FXS), Huntington's disease and spinal muscular atrophy (SMA).

ALS-linked PFN1 variants exhibit loss and gain of functions in the context of formin-induced actin polymerization

Profilin-1 (PFN1) plays important roles in modulating actin dynamics through binding both monomeric actin and proteins enriched with polyproline motifs. Mutations in PFN1 have been linked to the neurodegenerative disease amyotrophic lateral sclerosis (ALS). However, whether ALS-linked mutations affect PFN1 function has remained unclear. To address this question, we employed an unbiased proteomics analysis in mammalian cells to identify proteins that differentially interact with mutant and wild-type (WT) PFN1. These studies uncovered differential binding between two ALS-linked PFN1 variants, G118V and M114T, and select formin proteins. Furthermore, both variants augmented formin-mediated actin assembly relative to PFN1 WT. Molecular dynamics simulations revealed mutation-induced changes in the internal dynamic couplings within an alpha helix of PFN1 that directly contacts both actin and polyproline, as well as structural fluctuations within the actin- and polyproline-binding regions of PFN1. These data indicate that ALS-PFN1 variants have the potential for heightened flexibility in the context of the ternary actin-PFN1-polyproline complex during actin assembly. Conversely, PFN1 C71G was more severely destabilized than the other PFN1 variants, resulting in reduced protein expression in both transfected and ALS patient lymphoblast cell lines. Moreover, this variant exhibited loss-of-function phenotypes in the context of actin assembly. Perturbations in actin dynamics and assembly can therefore result from ALS-linked mutations in PFN1. However, ALS-PFN1 variants may dysregulate actin polymerization through different mechanisms that depend upon the solubility and stability of the mutant protein.

Mutations in Profilin 1 Cause Early-Onset Paget's Disease of Bone With Giant Cell Tumors

Paget's disease of bone (PDB) is a late-onset chronic progressive bone disease characterized by abnormal activation of osteoclasts that results in bone pain, deformities, and fractures. PDB is very rare in Asia. A subset of PDB patients have early onset and can develop malignant giant cell tumors (GCTs) of the bone (PDB/GCTs), which arise within Paget bone lesions; the result is a significantly higher mortality rate. SQSTM1, TNFRSF11A, OPG, VCP, and HNRNPA2B1 have been identified as pathogenic genes of PDB, and ZNF687 is the only confirmed gene to date known to cause PDB/GCT. However, the molecular mechanism underlying PDB/GCT has not been fully elucidated. Here, we investigate an extended Chinese pedigree with eight individuals affected by early-onset and polyostotic PDB, two of whom developed GCTs. We identified a heterozygous 4-bp deletion in the Profilin 1 (PFN1) gene (c.318_321delTGAC) by genetic linkage analysis and exome sequencing for the family. Sanger sequencing revealed another heterozygous 1-bp deletion in PFN1 (c.324_324delG) in a sporadic early-onset PDB/GCT patient, further proving its causative role. Interestingly, a heterozygous missense mutation of PFN1 (c.335 T > C) was identified in another PDB/GCT family, revealing that not only deletion but also missense mutations in PFN1 can cause PDB/GCT. Furthermore, we established a Pfn1-mutated mouse model (C57BL/6J mice) and successfully obtained Pagetic phenotypes in heterozygous mice, verifying loss of function of PFN1 as the cause of PDB/GCT development. In conclusion, our findings reveal mutations in PFN1 as the pathological mechanism in PDB/GCT, and we successfully established Pfn1-mutated mice as a suitable animal model for studying PDB-associated pathological mechanisms. The identification of PFN1 mutations has great diagnostic value for identifying PDB individuals predisposed toward developing GCTs. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The role of profilin-1 in cardiovascular diseases

Dynamic remodeling of the actin cytoskeleton is an essential feature for virtually all actin-dependent cellular processes, including cell migration, cell cycle progression, chromatin remodeling and gene expression, and even the DNA damage response. An altered actin cytoskeleton is a structural hallmark associated with numerous pathologies ranging from cardiovascular diseases to immune disorders, neurological diseases and cancer. The actin cytoskeleton in cells is regulated through the orchestrated actions of a myriad of actin-binding proteins. In this Review, we provide a brief overview of the structure and functions of the actin-monomer-binding protein profilin-1 (Pfn1) and then discuss how dysregulated expression of Pfn1 contributes to diseases associated with the cardiovascular system.

In silico studies reveal structural deviations of mutant profilin-1 and interaction with riluzole and edaravone in amyotrophic lateral sclerosis

This study aimed to investigate four of the eight PFN-1 mutations that are located near the actin-binding domain and determine the structural changes due to each mutant and unravel how these mutations alter protein structural behavior. Swapaa's command in UCSF chimera for generating mutations, FTMAP were employed and the data was analyzed by RMSD, RMSF graphs, Rg, hydrogen bonding analysis, and RRdisMaps utilizing Autodock4 and GROMACS. The functional changes and virtual screening, structural dynamics, and chemical bonding behavior changes, molecular docking simulation with two current FDA-approved drugs for ALS were investigated. The highest reduction and increase in Rg were found to exist in the G117V and M113T mutants, respectively. The RMSF data consistently shows changes nearby to this site. The in silico data described indicate that each of the mutations is capable of altering the structure of PFN-1 in vivo. The potential effect of riluzole and edaravone two FDA approved drugs for ALS, impacting the structural deviations and stabilization of the mutant PFN-1 is evaluated using in silico tools. Overall, the analysis of data collected reveals structural changes of mutant PFN-1 protein that may explain the neurotoxicity and the reason(s) for possible loss and gain of function of PFN-1 in the neurotoxic model of ALS.

Downregulation of TOP2 modulates neurodegeneration caused by GGGGCC expanded repeats

GGGGCC repeats in a non-coding region of the C9orf72 gene have been identified as a major genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. We previously showed that the GGGGCC expanded repeats alone were sufficient to cause neurodegeneration in Drosophila. Recent evidence indicates that GGGGCC expanded repeats can modify various gene transcriptomes. To determine the role of these genes in GGGGCC-mediated neurotoxicity, we screened an established Drosophila model expressing GGGGCC expanded repeats in this study. Our results showed that knockdown of the DNA topoisomerase II (Top2) gene can specifically modulate GGGGCC-associated neurodegeneration of the eye. Furthermore, chemical inhibition of Top2 or siRNA-induced Top2 downregulation could alleviate the GGGGCC-mediated neurotoxicity in Drosophila assessed by eye neurodegeneration and locomotion impairment. By contrast, upregulated Top2 levels were detected in Drosophila strains, and moreover, TOP2A level was also upregulated in Neuro-2a cells expressing GGGGCC expanded repeats, as well as in the brains of Sod1G93A model mice. This indicated that elevated levels of TOP2A may be involved in a pathway common to the pathophysiology of distinct ALS forms. Moreover, through RNA-sequencing, a total of 67 genes, involved in the pathways of intracellular signaling cascades, peripheral nervous system development, and others, were identified as potential targets of TOP2A to modulate GGGGCC-mediated neurodegeneration.

Mutant Profilin1 Aggregation in Amyotrophic Lateral Sclerosis: An in Vivo Biochemical Analysis

INTRODUCTION

Profilin1 (PFN1) is a ubiquitously expressed protein known for its function as a regulator of actin polymerization and dynamics. A recent discovery linked mutant PFN1 to Amyotrophic Lateral Sclerosis (ALS), which is a fatal and progressive motor neuron disease. We have also demonstrated that Gly118Val mutation in PFN1 is a cause of ALS, and the formation of aggregates containing mutant PFN1 may be a mechanism for motor neuron death. Hence, we were interested in investigating the aggregation of PFN1 further and searching for co-aggregated proteins in our mouse model overexpressing mutant PFN1.

METHODS

We investigated protein aggregation in several tissues of transgenic and notransgenic mice using western blotting. To further understand the neurotoxicity of mutant PFN1, we conducted a pull-down assay using an insoluble fraction of spinal cord lysates from hPFN1G118V transgenic mice. For this assay, we expressed His6-tagged PFN1WT and PFN1G118V in E. coli and purified these proteins using the Ni-NTA column.

RESULTS

In this study, we demonstrated that mutant PFN1 forms aggregate in the brain and spinal cord of hPFN1G118V mice, while WT-PFN1 remains soluble. Among these tissues, spinal cord lysates were found to have PFN1 bands at higher molecular weights recognized with anti-PFN1. Moreover, the pull-down assay using His6-PFN1G118V showed that Myelin Binding Protein (MBP) was present in the insoluble fraction.

CONCLUSION

Our analysis of PFN1 aggregation in vivo revealed further details of mutant PFN1 aggregation and its possible complex formation with other proteins, providing new insights into the ALS mechanism.