Neuronal Protein 3.1 Deficiency Leads to Reduced Cutaneous Scar Collagen Deposition and Tensile Strength due to Impaired Transforming Growth Factor-β1 to -β3 Translation

P311 Promotes IL-4 Receptor‒Mediated M2 Polarization of Macrophages to Enhance Angiogenesis for Efficient Skin Wound Healing

The transition from the proinflammatory phase to the prohealing phase in wound healing is essential for effective skin wound repair, which involves the balance of M1 and M2 polarization of wound-infiltrating macrophages. P311 plays an essential role in promoting wound closure by enhancing the biological function of epidermal stem cells, endothelial cells, and fibroblasts. Nevertheless, whether and how P311 regulates macrophage polarization remains unclear. In this study, we showed that P311 deficiency reduced the M2 polarization of macrophages, thereby attenuating the secretion of M2-like cytokines. The P311 deficiency prolonged the transition from the proinflammatory phase to the prohealing phase, accompanied by weakened angiogenesis and retarded granulation tissue formation, both of which coordinately hinder the healing of skin wounds. Mechanistically, P311 deficiency downregulated the expression of IL-4 receptor on macrophages, followed by less activation of the IL-4 receptor‒signal transducer and activator of transcription 6 signaling pathway, resulting in impaired M2 macrophage polarization. We further revealed that the mTOR signaling pathway was associated with the regulation of P311 on the expression of IL-4 receptor in macrophages. Thus, our study has highlighted the pivotal role of P311 in promoting the M2 polarization of macrophages for effective skin wound healing.

The emerging therapeutic targets for scar management: genetic and epigenetic landscapes

Background

Wound healing is a complex process including hemostasis, inflammation, proliferation, and remodeling during which an orchestrated array of biological and molecular events occurs to promote skin regeneration. Abnormalities in each step of the wound healing process lead to reparative rather than regenerative responses, thereby driving the formation of cutaneous scar. Patients suffering from scars represent serious health problems such as contractures, functional and esthetic concerns as well as painful, thick, and itchy complications, which generally decrease the quality of life and impose high medical costs. Therefore, therapies reducing cutaneous scarring are necessary to improve patients' rehabilitation.

Summary

Current approaches to remove scars, including surgical and nonsurgical methods, are not efficient enough, which is in principle due to our limited knowledge about underlying mechanisms of pathological as well as the physiological wound healing process. Thus, therapeutic interventions focused on basic science including genetic and epigenetic knowledge are recently taken into consideration as promising approaches for scar management since they have the potential to provide targeted therapies and improve the conventional treatments as well as present opportunities for combination therapy. In this review, we highlight the recent advances in skin regenerative medicine through genetic and epigenetic approaches to achieve novel insights for the development of safe, efficient, and reproducible therapies and discuss promising approaches for scar management.

Key Message

Genetic and epigenetic regulatory switches are promising targets for scar management, provided the associated challenges are to be addressed.

Serum collected from rats with myocardial infarction increases extracellular matrix accumulation by myofibroblasts isolated from myocardial infarction scar

The effect on extracellular matrix content is believed to be an average of several serum derived compounds acting in opposition. The aim of the study is to determine whether whole serum of rats with myocardial infarction may modify the accumulation of extracellular matrix in cultures of myofibroblasts isolated from the myocardial infarction scar. A second aim is to determine whether the tested serum can also degranulate the mast cells. Serum was collected from rats with sham myocardial infarction, rats with myocardial infarction induced by coronary artery ligation and control animals. The experiments were carried out on myocardial infarction scar myofibroblasts or mast cells from the peritoneal cavity. The cultures were divided into three groups containing eight cultures each: one treated with serum from control rats, from animals after sham operation or from those after myocardial infarction. In all groups, the serum was used at concentrations of 10%, 20% or 30%. The total collagen content (Woesner method) glycosaminoglycan level (Farandale method), cell proliferation (BrdU), histamine secretion from mast cells (spectrofluorymetry), β1 integrin and α-smooth muscle actin expression (flow cytometry) were evaluated. Isolated cells were α-smooth muscle actin positive and identified as myofibroblasts. Serum derived from rats with myocardial infarction increased collagen and glycosaminoglycan content in the cultures and modified myofibroblast proliferation in a concentration-dependent manner. The serum also results in an imbalance between collagen and glycosaminoglycan levels. The content of β1 integrin was not influenced by myocardial infarction serum. The serum of rats with myocardial infarction is involved in regulation of collagen and glycosaminoglycan content in myofibroblast cultures, as well as the modification of their proliferation. These changes were not accompanied with integrin β1 density variations. The serum of the myocardial infarction rats did not influence the mast cell degranulation.

Effects of IL-1β and TNF-α on the Expression of P311 in Vascular Endothelial Cells and Wound Healing in Mice

Objective

This study aimed to define the role of interleukine-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the expression of P311 in vascular endothelial cells (VECs) and in wound healing.

Methods

DAPI staining, a CCK-8 assay, cell migration assay, and an angiogenesis assay were used to assess the effects exerted by TNF-α and IL-1β at various concentrations on morphology, proliferation, migration, and angiogenesis of VECs. Western blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) models were employed to observe the effects exerted by proteins related to the nuclear factor-kappa B (NF-κB) signaling pathway and P311 mRNA expression. Bioinformatics analysis was performed on the binding sites of P311 and NF-κB. Finally, to investigate the effects of IL-1β and TNF-α on wound healing and the length of new epithelium in mice, we established a full-thickness wound defect model in mice. Immunohistochemistry was used to measure changes in P311, proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), CD31 (platelet endothelial cell adhesion molecule-1, PECAM-1/CD31), as well as other related proteins.

Results

When levels of TNF-α and IL-1β were both 20 ng/ml, their effects on cell proliferation, cytoskeleton protein expression, cell migration, and angiogenesis were the greatest (P < 0.05). IL-1β and TNF-α at moderate concentrations effectively promoted P311 mRNA and p-NF-κB protein expression (P < 0.05), while p-NF-K b protein expression was decreased (P < 0.05). Luciferase assays showed that P311 expression was also relatively greater when stimulated at moderate concentrations (P < 0.05), while relative expression was significantly lower when the p-NF-K b inhibitor CAPE was added (P < 0.05). On 7-day wound healing rate comparison, the control, IL-1β, IL-1βab, TNF-α, and TNF-αab groups were 18, 37, 35, 39, and 36%, respectively, while control group + P311 siRNA was 31% (P < 0.05). New epithelial length, granulation tissue thickness, and number of blood vessels trends were also the same. In the control group, P311 showed lower relative expression levels than the others (P < 0.05). P311 relative expression levels trended as follows: control group > IL-1βab > IL-1β > TNF-αab > TNF-α (P < 0.05).

Conclusion

When IL-1β and TNF-α concentrations are moderate, they effectively promote the proliferation, expression, migration, and angiogenesis of VECs, possibly by promoting the expression of the NF-K b pathway and thereby promoting the expression of P311. In vitro experiments on mice suggest that P311 effectively promotes wound healing, and its mechanism may be closely related to PCNA, CD31, and VEGF.

What Is the Impact of Depletion of Immunoregulatory Genes on Wound Healing? A Systematic Review of Preclinical Evidence

Cytokines and growth factors are known to play an important role in the skin wound closure process; however, in knockout organisms, the levels of these molecules can undergo changes that result in the delay or acceleration of this process. Therefore, we systematically reviewed evidence from preclinical studies about the main immunoregulatory molecules involved in skin repair through the analysis of the main mechanisms involved in the depletion of immunoregulatory genes, and we carried out a critical analysis of the methodological quality of these studies. We searched biomedical databases, and only original studies were analyzed according to the PRISMA guidelines. The included studies were limited to those which used knockout animals and excision or incision wound models without intervention. A total of 27 studies were selected; data for animal models, gene depletion, wound characteristics, and immunoregulatory molecules were evaluated and compared whenever possible. Methodological quality assessments were examined using the ARRIVE and SYRCLE's bias of risk tool. In our review, the extracellular molecules act more negatively in the wound healing process when silenced and the metabolic pathway most affected involved in these processes was TGF-β/Smad, and emphasis was given to the importance of the participation of macrophages in TGF-β signaling. Besides that, proinflammatory molecules were more evaluated than anti-inflammatory ones, and the main molecules evaluated were, respectively, TGF-β1, followed by VEGF, IL-6, TNF-α, and IL-1β. Overall, most gene depletions delayed wound healing, negatively influenced the concentrations of proinflammatory cytokines, and consequently promoted a decrease of inflammatory cell infiltration, angiogenesis, and collagen deposition, compromising the formation of granulation tissue. The studies presented heterogeneous data and exhibited methodological limitations; therefore, mechanistic and highly controlled studies are required to improve the quality of the evidence.

Butyrate alleviates diabetic kidney disease by mediating the miR-7a-5p/P311/TGF-β1 pathway

It has been reported that butyrate played an protect role in diabetic kidney disease (DKD) while the mechanism was still not clear. Transforming growth factor-β1 (TGF-β1) is the initial factor which triggers the profibrotic signaling cascades. P311 is an RNA-binding protein, which could stimulate TGF-β1 translation in several cell types. In our study, we found that supplementary of butyrate alleviated fibrosis and suppressed the expression of TGF-β1 and P311 in the kidney of db/db mice as well as high glucose (HG)-induced SV40-MES-13 cells. Overexpression of P311 offset the inhibition of butyrate on TGF-β1 in SV40-MES-13 cells. To make clear the mechanism of butyrate in regulating P311, microRNAs (miRNAs) of the SV40-MES-13 cells were sequenced. We found that miR-7a-5p was significantly decreased in the HG-induced SV40-MES-13 cells and the kidney of db/db mice, while giving butyrate reversed this change. Besides, miR-7a-5p could specifically target the 3' UTR of P311's mRNA and suppressed the expression of P311 in the SV40-MES-13 cells. Giving miR-7a-5p inhibitor blocked the inhibition of butyrate on P311 and TGF-β1. Introducing the miR-7a-5p agomir into db/db mice alleviated renal fibrosis and inhibit the expression of P311 and TGF-β1. In conclusion, butyrate alleviated DKD by mediating the miR-7a-5p/P311/TGF-β1 pathway.

Variability in protein cargo detection in technical and biological replicates of exosome-enriched extracellular vesicles

Exosomes are extracellular vesicles (EVs) of ~20-200 nm diameter that shuttle DNAs, RNAs, proteins and other biomolecules between cells. The large number of biomolecules present in exosomes demands the frequent use of high-throughput analysis. This, in turn, requires technical replicates (TRs), and biological replicates (BRs) to produce accurate results. As the number and abundance of identified biomolecules varies between replicates (Rs), establishing the replicate variability predicted for the event under study is essential in determining the number of Rs required. Although there have been few reports of replicate variability in high throughput biological data, none of them focused on exosomes. Herein, we determined the replicate variability in protein profiles found in exosomes released from 3 lung adenocarcinoma cell lines, H1993, A549 and H1975. Since exosome isolates are invariably contaminated by a small percentage of ~200-300 nm microvesicles, we refer to our samples as exosome-enriched EVs (EE-EVs). We generated BRs of EE-EVs from each cell line, and divided each group into 3 TRs. All Rs were analyzed by liquid chromatography/mass spectrometry (LC/MS/MS) and customized bioinformatics and biostatistical workflows (raw data available via ProteomeXchange: PXD012798). We found that the variability among TRs as well as BRs, was largely qualitative (protein present or absent) and higher among BRs. By contrast, the quantitative (protein abundance) variability was low, save for the H1975 cell line where the quantitative variability was significant. Importantly, our replicate strategy identified 90% of the most abundant proteins, thereby establishing the utility of our approach.

P311 Promotes Lung Fibrosis via Stimulation of Transforming Growth Factor-β1, -β2, and -β3 Translation

Interstitial lung fibrosis, a frequently idiopathic and fatal disease, has been linked to the increased expression of profibrotic transforming growth factor (TGF)-βs. P311 is an RNA-binding protein that stimulates TGF-β1, -β2, and -β3 translation in several cell types through its interaction with the eukaryotic translation initiation factor 3b. We report that P311 is switched on in the lungs of patients with idiopathic pulmonary fibrosis (IPF) and in the mouse model of bleomycin (BLM)-induced pulmonary fibrosis. To assess the in vivo role of P311 in lung fibrosis, BLM was instilled into the lungs of P311-knockout mice, in which fibrotic changes were significantly decreased in tandem with a reduction in TGF-β1, -β2, and -β3 concentration/activity compared with BLM-treated wild-type mice. Complementing these findings, forced P311 expression increased TGF-β concentration/activity in mouse and human lung fibroblasts, thereby leading to an activated phenotype with increased collagen production, as seen in IPF. Consistent with a specific effect of P311 on TGF-β translation, TGF-β1-, -β2-, and -β3-neutralizing antibodies downregulated P311-induced collagen production by lung fibroblasts. Furthermore, treatment of BLM-exposed P311 knockouts with recombinant TGF-β1, -β2, and -β3 induced pulmonary fibrosis to a degree similar to that found in BLM-treated wild-type mice. These studies demonstrate the essential function of P311 in TGF-β-mediated lung fibrosis. Targeting P311 could prove efficacious in ameliorating the severity of IPF while circumventing the development of autoimmune complications and toxicities associated with the use of global TGF-β inhibitors.

The Effects of Preoperative Steroid Therapy on Perioperative Morbidity and Mortality After Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVES

To identify the effects of preoperative steroid therapy on 30-day perioperative complications after adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Chronic steroid therapy has demonstrated therapeutic effects in the treatment of various medical conditions but is also known to be associated with surgical complications. There remains a gap in the literature regarding the impact of chronic steroid therapy in predisposing patients to perioperative complications after elective surgery for ASD.

METHODS

We performed a retrospective analysis of data from the 2008-2015 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were divided into two groups based on preoperative steroid therapy. Differences in baseline patient characteristics, comorbidities, and operative variables were assessed. Univariate analysis was performed to compare the incidence of perioperative complications. Multivariate stepwise logistic regression models were then used to adjust for baseline patient and operative variables in order to identify perioperative complications that were associated with preoperative steroid therapy.

RESULTS

We identified 7,936 patients who underwent surgery for ASD, of which 418 (5.3%) were on preoperative steroid therapy. Preoperative steroid therapy was an independent risk factor for four perioperative complications, including mortality (odds ratio [OR] 2.42, 95% confidence interval [CI] 1.30, 4.51; p = .005), wound dehiscence (OR 3.12, 95% CI 1.45, 6.70; p = .004), deep vein thrombosis (DVT) (OR 2.10, 95% CI 1.24, 3.55; p = .006), and blood transfusion (OR 1.34, 95% CI 1.08, 1.66; p < .007).

CONCLUSIONS

Patients on preoperative steroid therapy are at increased risk of 30-day mortality, wound dehiscence, DVT, and blood transfusion after surgery for ASD. An interdisciplinary approach to the perioperative management of steroid regimens is critical.

LEVEL OF EVIDENCE

Level III.

Reconstruction and Functional Annotation of P311 Protein-Protein Interaction Network Reveals Its New Functions

P311 is a highly conserved multifunctional protein. However, it does not belong to any established family of proteins, and its biological function has not been entirely determined. This study aims to reveal the unknown molecular and cellular function of P311. OCG (Overlapping Cluster Generator) is a clustering method used to partition a protein-protein network into overlapping clusters. Multifunctional proteins are at the intersection of relevant clusters. DAVID is an analytic tool used to extract biological meaning from a large protein list. Here we presented OD2 (OCG + DAVID + 2 human PPI datasets), a novel strategy to increase the likelihood to identify biological functions most pertinent to the multifunctional proteins. The principle of OD2 is that OCG prepares the protein lists from multifunctional protein relevant overlapping clusters, for a functional enrichment analysis by DAVID, and the similar functional enrichments, which occurs simultaneously when analyzing two human PPI datasets, are supposed to be the predicted functions. By applying OD2 to two reconstructed human PPI datasets, we supposed the function of the P311 in inflammatory responses, cell proliferation and coagulation, which were confirmed by the following biological experiments. Collectively, our study preliminarily found that P311 could play a role in inflammatory responses, cell proliferation and coagulation. Further studies are required to validate and elucidate the underlying mechanism.

Tissue cell differentiation and multicellular evolution via cytoskeletal stiffening in mechanically stressed microenvironments

Evolution of eukaryotes from simple cells to complex multicellular organisms remains a mystery. Our postulate is that cytoskeletal stiffening is a necessary condition for evolution of complex multicellular organisms from early simple eukaryotes. Recent findings show that embryonic stem cells are as soft as primitive eukaryotes-amoebae and that differentiated tissue cells can be two orders of magnitude stiffer than embryonic stem cells. Soft embryonic stem cells become stiff as they differentiate into tissue cells of the complex multicellular organisms to match their microenvironment stiffness. We perhaps see in differentiation of embryonic stem cells (derived from inner cell mass cells) the echo of those early evolutionary events. Early soft unicellular organisms might have evolved to stiffen their cytoskeleton to protect their structural integrity from external mechanical stresses while being able to maintain form, to change shape, and to move.

The Effects of Chronic Preoperative Steroid Therapy on Perioperative Complications Following Elective Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Chronic steroid therapy is used in the treatment of various inflammatory and autoimmune conditions, but it is known to be associated with adverse effects. There remains a gap in the literature regarding the role of chronic steroid therapy in predisposing patients to perioperative complications following elective posterior lumbar fusion (PLF). We aimed to identify the effects of chronic preoperative steroid therapy on 30-day perioperative complications in patients undergoing PLF.

METHODS

A retrospective analysis was performed using the 2011-2014 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. We identified 22 903 patients who underwent elective PLF. There were 849 patients (3.7%) who received chronic preoperative steroid therapy. Univariate and multivariate analyses were performed to examine steroid therapy as an independent risk factor for 30-day perioperative complications. A subgroup analysis of patients on chronic steroid therapy was then performed to identify additional patient characteristics that further increased the risk for perioperative complications.

RESULTS

Chronic preoperative steroid therapy was an independent risk factor for 7 perioperative complications, including superficial surgical site infection (SSI), deep SSI, wound dehiscence, urinary tract infection, pulmonary embolism, nonhome discharge, and readmission. Subgroup analysis demonstrated that morbid obesity further predisposed patients on chronic steroid therapy to an increased risk of superficial SSI and wound dehiscence.

CONCLUSIONS

Patients on chronic preoperative steroid therapy are at increased risk of multiple perioperative complications following elective PLF, particularly surgical site complications and venous thromboembolic events. This risk is further elevated in patients who are morbidly obese.

P311, Friend, or Foe of Tissue Fibrosis?

P311 was first identified by the group of Studler et al. (1993) in the developing brain. In healthy, but mainly in pathological tissues, P311 is implicated in cell migration and proliferation. Furthermore, evidence in models of tissue fibrosis points to the colocalization with and the stimulation of transforming growth factor β1 by P311. This review provides a comprehensive overview on P311 and discusses its potential as an anti-fibrotic target.

P311 Deficiency Leads to Attenuated Angiogenesis in Cutaneous Wound Healing

P311 was identified to markedly promote cutaneous wound healing by our group. Angiogenesis plays a key role in wound healing. In this study, we sought to define the role of P311 in skin wound angiogenesis. It was noted that P311 was expressed in endothelial cells in the dermis of murine and human skin wounds. The expression of P311 was confirmed in cultured murine dermal microvascular endothelial cells (mDMECs). Moreover, it was found that knockout of P311 could attenuate the formation of tubes and motility of mDMECs significantly in vitro. In the subcutaneous Matrigel implant model, the angiogenesis was reduced significantly in P311 knockout mice. In addition, wound healing was delayed in P311 knockout mice compared with that in the wild type. Granulation tissue formation during the defective wound healing showed thinner and blood vessel numbers in wound areas in P311 knockout mice were decreased significantly. A reduction in VEGF and TGFβ1 was also found in P311 KO mice wounds, which implied that P311 may modulate the exprssion of VEGF and TGFβ1 in wound healing. Together, our findings suggest that P311 plays an important role in angiogenesis in wound healing.