Periostin as a multifunctional modulator of the wound healing response

Periostin in the relation between periodontal disease and atherosclerotic coronary artery disease: A pilot randomized clinical study

OBJECTIVE

The aim of this study was to analyze the effects of periodontal treatment on markers of atherosclerotic coronary artery disease and circulating levels of periostin.

BACKGROUND

Periostin is necessary for periodontal stability, but it is highly present in atherosclerotic plaques. Treatment of periodontal disease, with low levels of local periostin, is thought to reduce systemic levels of periostin. Thus, this may contribute to cardiovascular health.

METHODS

A pilot randomized controlled clinical trial was designed to include patients with severe periodontal disease and history of atherosclerotic coronary artery disease. Samples of gingival crevicular fluid (GCF) and serum were collected before and after periodontal treatment by periodontal surgery or non-surgical therapy. The levels of several markers of inflammation and cardiovascular damage were evaluated including CRP, IFN-γ, IL-1ß, IL-10, MIP-1α, periostin, and TNF-α in GCF and CRP, Fibrinogen, IFN-γ, IL-1ß, IL-6, IL-10, L-Selectin, MIP-1α, Periostin, TNF-α, and vWF in serum.

RESULTS

A total of 22 patients with an average of 56 years old were recruited for participating in this study. Twenty of them were male. Most of them (82%) had suffered an acute myocardial event and underwent surgery for placing 1, 2, or 3 stents in the coronary arteries more than 6 months ago but less than 1 year. The treatment of periodontal disease resulted in an overall improvement of all periodontal parameters. Regarding the evaluation of GCF and serum, a significant increase of periostin in the GCF was observed after periodontal surgery. In contrast, although other markers in GCF and serum improved, no significant correlations were found.

CONCLUSION

Treatment of periodontal disease through periodontal surgery induces a local and transient increase in the levels of periostin in the gingival crevicular fluid. The effects on systemic markers of inflammation and cardiovascular function have not been confirmed.

Exclusive expression of KANK4 promotes myofibroblast mobility in keloid tissues

Keloids are characterized by abnormal wound healing with excessive accumulation of extracellular matrix. Myofibroblasts are the primary contributor to extracellular matrix secretion, playing an essential role in the wound healing process. However, the differences between myofibroblasts involved in keloid formation and normal wound healing remain unclear. To identify the specific characteristics of keloid myofibroblasts, we initially assessed the expression levels of well-established myofibroblast markers, α-smooth muscle actin (α-SMA) and transgelin (TAGLN), in scar and keloid tissues (n = 63 and 51, respectively). Although myofibroblasts were present in significant quantities in keloids and immature scars, they were absent in mature scars. Next, we conducted RNA sequencing using myofibroblast-rich areas from keloids and immature scars to investigate the difference in RNA expression profiles among myofibroblasts. Among significantly upregulated 112 genes, KN motif and ankyrin repeat domains 4 (KANK4) was identified as a specifically upregulated gene in keloids. Immunohistochemical analysis showed that KANK4 protein was expressed in myofibroblasts in keloid tissues; however, it was not expressed in any myofibroblasts in immature scar tissues. Overexpression of KANK4 enhanced cell mobility in keloid myofibroblasts. Our results suggest that the KANK4-mediated increase in myofibroblast mobility contributes to keloid pathogenesis.

Simultaneous Expression of CD70 and POSTN in Cancer-Associated Fibroblasts Predicts Worse Survival of Colorectal Cancer Patients

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide, with high morbidity and mortality rates. The evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) that modulate cancer cell proliferation, invasion, metastasis, and tumor immunity, including in CRC, has been attracting attention. The present study examined the expression status of CD70 and POSTN in CRC and analyzed their association with clinicopathological features and clinical outcomes. In the present study, in total 15% (40/269) and 44% (119/269) of cases exhibited CD70 and POSTN expression on CAFs, respectively. Co-expression of CD70 and POSTN was detected in 8% (21/269) of patients. Fluorescent immunohistochemistry identified the co-expression of CD70 and POSTN with FAP and PDPN, respectively. ACTA2 was not co-expressed with CD70 or POSTN in CRC CAFs. CRC with CD70+/POSTN+ status in CAFs was significantly associated with distant organ metastasis (p = 0.0020) or incomplete resection status (p = 0.0011). CD70+/POSTN+ status tended to associate with advanced pT stage (p = 0.032) or peritoneal metastasis (p = 0.0059). Multivariate Cox hazards regression analysis identified CD70+/POSTN+ status in CAFs [hazard ratio (HR) = 3.78] as a potential independent risk factor. In vitro experiments revealed the activated phenotypes of colonic fibroblasts induced by CD70 and POSTN, while migration and invasion assays identified enhanced migration and invasion of CRC cells co-cultured with CD70- and POSTN-expressing colonic fibroblasts. On the basis of our observations, CD70 and POSTN immunohistochemistry can be used in the prognostication of CRC patients. CRC CAFs may be a promising target in the treatment of CRC patients.

Clock gene Per2 modulates epidermal tissue repair in vivo

Wound healing can be influenced by genes that control the circadian cycle, including Per2 and BMAL1, which coordinate the functions of several organs, including the skin. The aim of the study was to evaluate the role of PER2 during experimental skin wound healing. Two groups (control and Per2-KO), consisting of 14 male mice each, were anesthetized by inhalation, and two 6 mm wounds were created on their dorsal skin using a punch biopsy. A silicone ring was sutured around the wound perimeter to restrict contraction. The wound healing process was clinically measured daily (closure index) until complete wound repair. On Day 6, histomorphometric analysis was performed using the length and thickness of the epithelial migration tongue, in addition to counting vessels underlying the lesion by immunofluorescence assay and maturation of collagen fibers through picrosirius staining. Bromodeoxyuridine (BrdU) incorporation and quantification were performed using the subcutaneous injection technique 2 h before euthanasia and through immunohistochemical analysis of the proliferative index. In addition, the qualitative analysis of myofibroblasts and periostin distribution in connective tissue was performed by immunofluorescence. Statistically significant differences were observed in the healing time between the experimental groups (means: 15.5 days for control mice and 13.5 days for Per2-KO; p = 0.001). The accelerated healing observed in the Per2-KO group (p < 0.05) was accompanied by statistical differences in wound diameter and length of the migrating epithelial tongue (p = 0.01) compared to the control group. Regarding BrdU immunoreactivity, higher expression was observed in the intact epithelium of Per2-KO animals (p = 0.01), and this difference compared to control was also present, to a lesser extent, at the wound site (p = 0.03). Immunofluorescence in the connective tissue underlying the wound showed a higher angiogenic potential in the Per2-KO group in the intact tissue area and the wound region (p < 0.01), where increased expression of myofibroblasts was also observed. Qualitative analysis revealed the distribution of periostin protein and collagen fibers in the connective tissue underlying the wound, with greater organization and maturation during the analyzed period. Our research showed that the absence of the Per2 gene positively impacts the healing time of the skin in vivo. This acceleration depends on the increase of epithelial proliferative and angiogenic capacity of cells carrying the Per2 deletion.

Expression of the Pro-Fibrotic Marker Periostin in a Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is characterised by fibrotic tissue deposition in skeletal muscle. We assessed the role of periostin in fibrosis using mdx mice, an established DMD murine model, for which we conducted a thorough examination of periostin expression over a year. RNA and protein levels in diaphragm (DIA) muscles were assessed and complemented by a detailed histological analysis at 5 months of age. In dystrophic DIAs, periostin (Postn) mRNA expression significantly exceeded that seen in wildtype controls at all timepoints analysed, with the highest expression at 5 months of age (p < 0.05). We found Postn to be more consistently highly expressed at the earlier timepoints compared to established markers of fibrosis like transforming growth factor-beta 1 (Tgf-β1) and connective tissue growth factor (Ctgf). Immunohistochemistry confirmed a significantly higher periostin protein expression in 5-month-old mdx mice compared to age-matched healthy controls (p < 0.01), coinciding with a significant fibrotic area percentage (p < 0.0001). RT-qPCR also indicated an elevated expression of Tgf-β1, Col1α1 (collagen type 1 alpha 1) and Ctgf in mdx DIAs compared to wild type controls (p < 0.05) at 8- and 12-month timepoints. Accordingly, immunoblot quantification demonstrated elevated periostin (3, 5 and 8 months, p < 0.01) and Tgf-β1 (8 and 12 months, p < 0.001) proteins in the mdx muscle. These findings collectively suggest that periostin expression is a valuable marker of fibrosis in this relevant model of DMD. They also suggest periostin as a potential contributor to fibrosis development, with an early onset of expression, thereby offering the potential for timely therapeutic intervention and its use as a biomarker in muscular dystrophies.

Identification of Periostin as a critical niche for myofibroblast dynamics and fibrosis during tendon healing

Tendon injuries are a major clinical problem, with poor patient outcomes caused by abundant scar tissue deposition during healing. Myofibroblasts play a critical role in the initial restoration of structural integrity after injury. However, persistent myofibroblast activity drives the transition to fibrotic scar tissue formation. As such, disrupting myofibroblast persistence is a key therapeutic target. While myofibroblasts are typically defined by the presence of αSMA+ stress fibers, αSMA is expressed in other cell types including the vasculature. As such, modulation of myofibroblast dynamics via disruption of αSMA expression is not a translationally tenable approach. Recent work has demonstrated that Periostin-lineage (PostnLin) cells are a precursor for cardiac fibrosis-associated myofibroblasts. In contrast to this, here we show that PostnLin cells contribute to a transient αSMA+ myofibroblast population that is required for functional tendon healing, and that Periostin forms a supportive matrix niche that facilitates myofibroblast differentiation and persistence. Collectively, these data identify the Periostin matrix niche as a critical regulator of myofibroblast fate and persistence that could be targeted for therapeutic manipulation to facilitate regenerative tendon healing.

Effect of Bioactive Glasses and Basic Fibroblast Growth Factor on Dental Pulp Cells

Ideal regeneration of hard tissue and dental pulp has been reported with the use of a combination of bioactive glass and basic fibroblast growth factor (bFGF). However, no previous study has investigated the molecular mechanisms underlying the processes induced by this combination in dental pulp cells. This study aimed to examine the cellular phenotype and transcriptional changes induced by the combination of bioactive glass solution (BG) and bFGF in dental pulp cells using phase-contrast microscopy, a cell counting kit-8 assay, alkaline phosphatase staining, and RNA sequence analysis. bFGF induced elongation of the cell process and increased the number of cells. Whereas BG did not increase ALP activity, it induced extracellular matrix-related genes in the dental pulp. In addition, the combination of BG and bFGF induces gliogenesis-related genes in the nervous system. This is to say, bFGF increased the viability of dental pulp cells, bioactive glass induced odontogenesis, and a dual stimulation with bioactive glass and bFGF induced the wound healing of the nerve system in the dental pulp. Taken together, bioactive glass and bFGF may be useful for the regeneration of the dentin-pulp complex.

ECM-Focused Proteomic Analysis of Ear Punch Regeneration in Acomys Cahirinus

In mammals, significant injury is generally followed by the formation of a fibrotic scar which provides structural integrity but fails to functionally restore damaged tissue. Spiny mice of the genus Acomys represent the first example of full skin autotomy in mammals. Acomys cahirinus has evolved extremely weak skin as a strategy to avoid predation and is able to repeatedly regenerate healthy tissue without scar after severe skin injury or full-thickness ear punches. Extracellular matrix (ECM) composition is a critical regulator of wound repair and scar formation and previous studies have suggested that alterations in its expression may be responsible for the differences in regenerative capacity observed between Mus musculus and A. cahirinus , yet analysis of this critical tissue component has been limited in previous studies by its insolubility and resistance to extraction. Here, we utilize a 2-step ECM-optimized extraction to perform proteomic analysis of tissue composition during wound repair after full-thickness ear punches in A. cahirinus and M. musculus from weeks 1 to 4 post-injury. We observe changes in a wide range of ECM proteins which have been previously implicated in wound regeneration and scar formation, including collagens, coagulation and provisional matrix proteins, and matricryptic signaling peptides. We additionally report differences in crosslinking enzyme activity and ECM protein solubility between Mus and Acomys. Furthermore, we observed rapid and sustained increases in CD206, a marker of pro-regenerative M2 macrophages, in Acomys, whereas little or no increase in CD206 was detected in Mus. Together, these findings contribute to a comprehensive understanding of tissue cues which drive the regenerative capacity of Acomys and identify a number of potential targets for future pro-regenerative therapies.

Influence of periostin on the development of fibrocartilage layers of anterior cruciate ligament insertion

BACKGROUND

Periostin (Postn) is thought to play a role in the formation of anterior cruciate ligament (ACL) insertion. However, the influence of Postn on the development of ACL insertion requires further understanding. This study aimed to clarify the influence of Postn on the development of fibrocartilage layers of ACL insertion.

HYPOTHESIS

We hypothesized that Postn would influence the development of fibrocartilage layers of ACL insertion.

MATERIALS AND METHODS

C57BL/6N wild-type (Postn+/+; n=54) and Postn knockout (Postn-/-; n=54) mice were used in this study. Six animals were euthanized at 1 d and 1, 2, 3, 4, 6, 8, 10, and 12 weeks of age in each group. The chondrocyte number, proliferation, apoptosis, safranin O-stained glycosaminoglycan (GAG) area, type II collagen staining area, tidemark length, and insertion width were evaluated.

RESULTS

Chondrocyte proliferation was high up to 2 weeks in Postn+/+, while low at age 1 d; it was, especially lower in Postn-/- than in Postn+/+ at age 1 d and 1 week. Chondrocyte apoptosis was high up to age 8 weeks in Postn+/+ and at 6 weeks in Postn-/-; it was especially higher in Postn-/- than in Postn+/+ at age 1 week. The GAG stained area was thickest for age 1 d to 4 weeks in Postn+/+ and for age 2 to 6 weeks in Postn-/-. The type II collagen staining area in Postn+/+ was thicker than that in Postn-/- at age 6 and 8 weeks. The tidemark length in Postn+/+ was longer than that in Postn-/- from age 8 to 12 weeks. The insertion width in Postn+/+ was longer than that in Postn-/- from age 1 to 3 weeks.

DISCUSSION

Postn decreased cell proliferation in the early postnatal phase and influenced the development of the fibrocartilage layer extracellular matrix of ACL insertion in mice. Postn may contribute to the development of methods for regeneration of the ACL insertion.

LEVEL OF EVIDENCE

V; controlled laboratory study.

Identification of Periostin as a critical niche for myofibroblast dynamics and fibrosis during tendon healing

Tendon injuries are a major clinical problem, with poor patient outcomes caused by abundant scar tissue deposition during healing. Myofibroblasts play a critical role in the initial restoration of structural integrity after injury. However, persistent myofibroblast activity drives the transition to fibrotic scar tissue formation. As such, disrupting myofibroblast persistence is a key therapeutic target. While myofibroblasts are typically defined by the presence of αSMA+ stress fibers, αSMA is expressed in other cell types including the vasculature. As such, modulation of myofibroblast dynamics via disruption of αSMA expression is not a translationally tenable approach. Recent work has demonstrated that Periostin-lineage (PostnLin) cells are a precursor for cardiac fibrosis-associated myofibroblasts. In contrast to this, here we show that PostnLin cells contribute to a transient αSMA+ myofibroblast population that is required for functional tendon healing, and that Periostin forms a supportive matrix niche that facilitates myofibroblast differentiation and persistence. Collectively, these data identify the Periostin matrix niche as a critical regulator of myofibroblast fate and persistence that could be targeted for therapeutic manipulation to facilitate regenerative tendon healing.

Genomic, Transcriptomic, and Proteomic Depiction of Induced Pluripotent Stem Cells-Derived Smooth Muscle Cells As Emerging Cellular Models for Arterial Diseases

BACKGROUND

Vascular smooth muscle cells (SMCs) plasticity is a central mechanism in cardiovascular health and disease. We aimed at providing cellular phenotyping, epigenomic and proteomic depiction of SMCs derived from induced pluripotent stem cells and evaluating their potential as cellular models in the context of complex diseases.

METHODS

Human induced pluripotent stem cell lines were differentiated using RepSox (R-SMCs) or PDGF-BB (platelet-derived growth factor-BB) and TGF-β (transforming growth factor beta; TP-SMCs), during a 24-day long protocol. RNA-Seq and assay for transposase accessible chromatin-Seq were performed at 6 time points of differentiation, and mass spectrometry was used to quantify proteins.

RESULTS

Both induced pluripotent stem cell differentiation protocols generated SMCs with positive expression of SMC markers. TP-SMCs exhibited greater proliferation capacity, migration and lower calcium release in response to contractile stimuli, compared with R-SMCs. Genes involved in the contractile function of arteries were highly expressed in R-SMCs compared with TP-SMCs or primary SMCs. R-SMCs and coronary artery transcriptomic profiles were highly similar, characterized by high expression of genes involved in blood pressure regulation and coronary artery disease. We identified FOXF1 and HAND1 as key drivers of RepSox specific program. Extracellular matrix content contained more proteins involved in wound repair in TP-SMCs and higher secretion of basal membrane constituents in R-SMCs. Open chromatin regions of R-SMCs and TP-SMCs were significantly enriched for variants associated with blood pressure and coronary artery disease.

CONCLUSIONS

Both induced pluripotent stem cell-derived SMCs models present complementary cellular phenotypes of high relevance to SMC plasticity. These cellular models present high potential to study functional regulation at genetic risk loci of main arterial diseases.

Phase-specific signatures of wound fibroblasts and matrix patterns define cancer-associated fibroblast subtypes

Healing wounds and cancers present remarkable cellular and molecular parallels, but the specific roles of the healing phases are largely unknown. We developed a bioinformatics pipeline to identify genes and pathways that define distinct phases across the time-course of healing. Their comparison to cancer transcriptomes revealed that a resolution phase wound signature is associated with increased severity in skin cancer and enriches for extracellular matrix-related pathways. Comparisons of transcriptomes of early- and late-phase wound fibroblasts vs skin cancer-associated fibroblasts (CAFs) identified an "early wound" CAF subtype, which localizes to the inner tumor stroma and expresses collagen-related genes that are controlled by the RUNX2 transcription factor. A "late wound" CAF subtype localizes to the outer tumor stroma and expresses elastin-related genes. Matrix imaging of primary melanoma tissue microarrays validated these matrix signatures and identified collagen- vs elastin-rich niches within the tumor microenvironment, whose spatial organization predicts survival and recurrence. These results identify wound-regulated genes and matrix patterns with prognostic potential in skin cancer.

Periostin Plasma Levels and Changes on Physical and Cognitive Capacities in Community-Dwelling Older Adults

Periostin, involved in extracellular matrix development and support, has been shown to be elevated in senescent tissues and fibrotic states, transversal signatures of aging. We aimed to explore associations between plasma periostin and physical and cognitive capacity evolution among older adults. Our hypothesis was that higher levels of plasma periostin will be associated with worse physical and mental capacities along time. Analyses included 1 096 participants (mean age = 75.3 years ± 4.4; 63.9% women) from the Multidomain Alzheimer Preventive Trial. Periostin levels (pg/mL) were measured in plasma collected at year 1. Periostin was used in continuous variable, and as a dichotomous variable highest quartile (POSTN+) versus lowest 3 quartiles (POSTN-) were used. Outcomes were measured annually over 4 years and included: gait speed (GS), short physical performance battery (SPPB) score, 5-times sit-to-stand test (5-STS), and handgrip strength (HS) as physical and cognitive composite z-score (CCS) and the Mini-Mental State Examination (MMSE) as cognitive endpoints. Plasma periostin as a continuous variable was associated with the worsening of physical and cognitive capacities over 4 years of follow-up, specifically the SPPB score, the 5-STS, and CCS in full-adjusted models. POSTN+ was associated with worse evolution in the physical (GS: [β = -0.057, 95% confidence interval (CI) = -0.101, -0.013], SPPB score [β = -0.736, 95% CI = -1.091, -0.381], 5-STS [β = 1.681, 95% CI = 0.801, 2.561]) as well as cognitive (CCS [β = -0.215, 95% CI = -0.335, -0.094]) domains compared to POSTN- group. No association was found with HS or the MMSE score. Our study showed for the first time that increased plasma periostin levels were associated with declines in both physical and cognitive capacities in older adults over a 4-year follow-up. Further research is needed to evaluate whether periostin might be used as a predictive biomarker of functional decline at an older age.

Stromal POSTN Enhances Motility of Both Cancer and Stromal Cells and Predicts Poor Survival in Colorectal Cancer

Evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) has rapidly been accumulating. To uncover clinicopathological importance of periostin (POSTN) expression in colorectal cancer (CRC), the present study immunohistochemically examined its expression status. Furthermore, to reveal its mechanisms involved, molecular experiments were performed. In CRC tissues, 44% of the cases (119/269) exhibited POSTN expression in the CAFs. In contrast, CRC cells expressed POSTN at almost undetectable levels. Survival analyses identified that patients with POSTN-positive CRC had a significantly worse 5-year survival rate (63.2% vs. 81.2%; p = 0.011). Univariate analyses revealed that POSTN positivity was associated with peritoneal (p = 0.0031) and distant organ metastasis (p < 0.001). Furthermore, immunohistochemical analyses identified a significant association between POSTN and p53 complete loss status in CRC cells. Decorin and fibroblast activation protein expression in CAFs was also associated with POSTN. POSTN significantly enhanced the migration of both CRC cells and fibroblasts with FAK and AKT or STAT3 activation, and co-culture assays demonstrated the communication between CRC cells and fibroblasts, which enhanced STAT3 activation in fibroblasts. On the basis of our results, we speculated that stromal POSTN accelerated metastasis via stromal remodeling capacity and activated the migration of both tumor and stromal cells.

Agonist (P1) Antibody Converts Stem Cells into Migrating Beta-Like Cells in Pancreatic Islets

Tissue regeneration is the ultimate treatment for many degenerative diseases, however, repair and regeneration of damaged organs or tissues remains a challenge. Previously, we showed that B1 Ab and H3 Ab induce stem cells to differentiate into microglia and brown adipocyte-like cells, while trafficking to the brain and heart, respectively. Here, we present data showing that another selected agonist antibody, P1 antibody, induces the migration of cells to the pancreatic islets and differentiates human stem cells into beta-like cells. Interestingly, our results suggest the purified P1 Ab induces beta-like cells from fresh, human CD34⁺ hematopoietic stem cells and mouse bone marrow. In addition, stem cells with P1 Ab bound to expressed periostin (POSTN), an extracellular matrix protein that regulates tissue remodeling, selectively migrate to mouse pancreatic islets. Thus, these results confirm that our in vivo selection system can be used to identify antibodies from our library which are capable of inducing stem cell differentiation and cell migration to select tissues for the purpose of regenerating and remodeling damaged organ systems.

Dual Role of Fibroblasts Educated by Tumour in Cancer Behavior and Therapeutic Perspectives

Tumours are complex systems with dynamic interactions between tumour cells, non-tumour cells, and extracellular components that comprise the tumour microenvironment (TME). The majority of TME's cells are cancer-associated fibroblasts (CAFs), which are crucial in extracellular matrix (ECM) construction, tumour metabolism, immunology, adaptive chemoresistance, and tumour cell motility. CAF subtypes have been identified based on the expression of protein markers. CAFs may act as promoters or suppressors in tumour cells depending on a variety of factors, including cancer stage. Indeed, CAFs have been shown to promote tumour growth, survival and spread, and secretome changes, but they can also slow tumourigenesis at an early stage through mechanisms that are still poorly understood. Stromal-cancer interactions are governed by a variety of soluble factors that determine the outcome of the tumourigenic process. Cancer cells release factors that enhance the ability of fibroblasts to secrete multiple tumour-promoting chemokines, acting on malignant cells to promote proliferation, migration, and invasion. This crosstalk between CAFs and tumour cells has given new prominence to the stromal cells, from being considered as mere physical support to becoming key players in the tumour process. Here, we focus on the concept of cancer as a non-healing wound and the relevance of chronic inflammation to tumour initiation. In addition, we review CAFs heterogeneous origins and markers together with the potential therapeutic implications of CAFs "re-education" and/or targeting tumour progression inhibition.

Self-amplifying loop of NF-κB and periostin initiated by PIEZO1 accelerates mechano-induced senescence of nucleus pulposus cells and intervertebral disc degeneration

Abnormal mechanical load is a main risk factor of intervertebral disc degeneration (IDD), and cellular senescence is a pathological change in IDD. In addition, extracellular matrix (ECM) stiffness promotes human nucleus pulposus cells (hNPCs) senescence. However, the molecular mechanism underlying mechano-induced cellular senescence and IDD progression is not yet fully elucidated. First, we demonstrated that mechano-stress promoted hNPCs senescence via NF-κB signaling. Subsequently, we identified periostin as the main mechano-responsive molecule in hNPCs through unbiased sequencing, which was transcriptionally upregulated by NF-κB p65; moreover, secreted periostin by senescent hNPCs further promoted senescence and upregulated the catabolic process in hNPCs through activating NF-κB, forming a positive loop. Both Postn (encoding periostin) knockdown via siRNA and periostin inactivation via neutralizing antibodies alleviated IDD and NPCs senescence. Furthermore, we found that mechano-stress initiated the positive feedback of NF-κB and periostin via PIEZO1. PIEZO1 activation by Yoda1 induced severe IDD in rat tails without compression, and Postn knockdown alleviated the Yoda1-induced IDD in vivo. Here, we reported for the first time that self-amplifying loop of NF-κB and periostin initiated via PIEZO1 under mechano-stress accelerated NPCs senescence, leading to IDD. Furthermore, periostin neutralizing antibodies, which may serve as potential therapeutic agents for IDD, interrupted this loop.

Periostin Contributes to Fibrocartilage Layer Growth of the Patella Tendon Tibial Insertion in Mice

Background and Objectives: The influence of periostin on the growth of the patella tendon (PT) tibial insertion is unknown. The research described here aimed to reveal the contribution of periostin to the growth of fibrocartilage layers of the PT tibial insertion using periostin knockout mice. Materials and Methods: In both the wild-type (WD; C57BL/6N, periostin +/+; n = 54) and periostin knockout (KO; periostin −/−; n = 54) groups, six mice were euthanized on day 1 and at 1, 2, 3, 4, 6, 8, 10, and 12 weeks of age. Chondrocyte proliferation and apoptosis, number of chondrocytes, safranin O-stained glycosaminoglycan (GAG) area, staining area of type II collagen, and length of the tidemark were investigated. Results: Chondrocyte proliferation and apoptosis in KO were lower than those in WD on day 1 and at 1, 4, and 8 weeks and on day 1 and at 4, 6, and 12 weeks, respectively. Although the number of chondrocytes in both groups gradually decreased, it was lower in KO than in WD on day 1 and at 8 and 12 weeks. In the extracellular matrix, the GAG-stained area in KO was smaller than that in WD on day 1 and at 1, 4, 8, 10, and 12 weeks. The staining area of type II collagen in KO was smaller than that in WD at 8 weeks. The length of the tidemark in KO was shorter than that in WD at 4 and 6 weeks. Conclusion: Loss of periostin led to decreased chondrocyte proliferation, chondrocyte apoptosis, and the number of chondrocytes in the growth process of the PT tibial insertion. Moreover, periostin decreased and delayed GAG and type II collagen production and delayed tidemark formation in the growth process of the PT tibial insertion. Periostin can, therefore, contribute to the growth of fibrocartilage layers in the PT tibial insertion. Periostin deficiency may result in incomplete growth of the PT tibial insertion.

Analysis of Keratinocytic Exosomes from Diabetic and Nondiabetic Mice by Charge Detection Mass Spectrometry

Unresolved inflammation compromises diabetic wound healing. Recently, we reported that inadequate RNA packaging in murine wound-edge keratinocyte-originated exosomes (Exoκ) leads to persistent inflammation [Zhou, X. ACS Nano 2020, 14(10), 12732-12748]. Herein, we use charge detection mass spectrometry (CDMS) to analyze intact Exoκ isolated from a 5 day old wound-edge tissue of diabetic mice and a heterozygous nondiabetic littermate control group. In CDMS, the charge (z) and mass-to-charge ratio (m/z) of individual exosome particles are measured simultaneously, enabling the direct analysis of masses in the 1-200 MDa range anticipated for exosomes. These measurements reveal a broad mass range for Exoκ from ∼10 to >100 MDa. The m and z values for these exosomes appear to fall into families (subpopulations); a statistical modeling analysis partially resolves ∼10-20 Exoκ subpopulations. Complementary proteomics, immunofluorescence, and electron microscopy studies support the CDMS results that Exoκ from diabetic and nondiabetic mice vary substantially. Subpopulations having high z (>650) and high m (>44 MDa) are more abundant in nondiabetic animals. We propose that these high m and z particles may arise from differences in cargo packaging. The veracity of this idea is discussed in light of other recent CDMS results involving genome packaging in vaccines, as well as exosome imaging experiments. Characterization of intact exosome particles based on the physical properties of m and z provides a new means of investigating wound healing and suggests that CDMS may be useful for other pathologies.

Adipose-derived stromal cells increase the formation of collagens through paracrine and juxtacrine mechanisms in a fibroblast co-culture model utilizing macromolecular crowding

Background

Adipose-derived stromal cells (ASCs) possess a multitude of regenerative capabilities, which include immunomodulation, angiogenesis, and stimulation of extracellular matrix (ECM) remodeling. However, the underlying mechanisms leading to ECM remodeling remain largely elusive and highlight the need for functional in vitro models for mode of action studies. Therefore, the purpose of this study was to develop an in vitro co-culture model to investigate the capabilities of ASCs to modulate fibroblasts and ECM.

Methods

An ECM in vitro model with ASCs and normal human dermal fibroblasts (NHDFs) was established utilizing macromolecular crowding, ascorbic acid, and TGF-β stimulation. Paracrine and juxtacrine co-cultures were created using transwell inserts and cell cultures with direct cell–cell contacts. The cultures were screened using RT² PCR Profiler Arrays; the protein levels of myofibroblast differentiation marker alpha smooth muscle actin (αSMA) and ECM remodeling enzymes were analyzed using western blot on cell lysates; the formation of collagen type I, III, VI, and fibronectin was investigated using ELISA on culture supernatants; and the deposition of collagens was analyzed using immunocytochemistry.

Results

TGF-β stimulation of NHDF monocultures increased the expression of 18 transcripts relevant for ECM formation and remodeling, the protein levels of αSMA and matrix metalloproteinase-2 (MMP-2), the formation of collagen type I, III, VI, and fibronectin, and the deposition of collagen type I and VI and decreased the protein levels of MMP-14. Inclusion of ASCs in the ECM co-culture model increased the formation of collagen type I and III through paracrine mechanisms and the formation of collagen type VI through juxtacrine mechanisms.

Conclusions

The co-culture model provides effective stimulation of NHDF monocultures by TGF-β for enhanced formation and deposition of ECM. In the model, ASCs induce changes in ECM by increasing formation of collagen type I, III and VI. The obtained results could guide further investigations of ASCs’ capabilities and underlying mechanisms related to ECM formation and remodeling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02923-y.

Stromal Factors as a Target for Immunotherapy in Melanoma and Non-Melanoma Skin Cancers

Immune checkpoint inhibitors (ICIs), such as anti-programmed cell death 1 (PD1) antibodies (Abs) and anti-cytotoxic T-lymphocyte associated protein 4 (CTLA4) Abs, have been widely administered for not only advanced melanoma, but also various non-melanoma skin cancers. Since profiles of tumor-infiltrating leukocytes (TILs) play important roles in immunotherapy using ICIs, it is important to evaluate cancer stromal cells such as tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs), as well as stromal extracellular matrix protein, to predict the efficacy of ICIs. This review article focuses particularly on TAMs and related factors. Among TILs, TAMs and their related factors could be the optimal biomarkers for immunotherapy such as anti-PD1 Ab therapy. According to the studies presented, TAM-targeting therapies for advanced melanoma and non-melanoma skin cancer will develop in the future.

Interacting Effects of Sea Louse (Lepeophtheirus salmonis) Infection and Formalin-Killed Aeromonas salmonicida on Atlantic Salmon Skin Transcriptome

Lepeophtheirus salmonis (sea lice) and bacterial co-infection threatens wild and farmed Atlantic salmon performance and welfare. In the present study, pre-adult L. salmonis-infected and non-infected salmon were intraperitoneally injected with either formalin-killed Aeromonas salmonicida bacterin (ASAL) or phosphate-buffered saline (PBS). Dorsal skin samples from each injection/infection group (PBS/no lice, PBS/lice, ASAL/no lice, and ASAL/lice) were collected at 24 h post-injection and used for transcriptome profiling using a 44K salmonid microarray platform. Microarray results showed no clear inflammation gene expression signatures and revealed extensive gene repression effects by pre-adult lice (2,189 down and 345 up-regulated probes) in the PBS-injected salmon (PBS/lice vs. PBS/no lice), which involved basic cellular (e.g., RNA and protein metabolism) processes. Lice repressive effects were not observed within the group of ASAL-injected salmon (ASAL/lice vs. ASAL/no lice); on the contrary, the observed skin transcriptome changes –albeit of lesser magnitude (82 up and 1 down-regulated probes)– suggested the activation in key immune and wound healing processes (e.g., neutrophil degranulation, keratinocyte differentiation). The molecular skin response to ASAL was more intense in the lice-infected (ASAL/lice vs. PBS/lice; 272 up and 11 down-regulated probes) than in the non-infected fish (ASAL/no lice vs. PBS/no lice; 27 up-regulated probes). Regardless of lice infection, the skin’s response to ASAL was characterized by the putative activation of both antibacterial and wound healing pathways. The transcriptomic changes prompted by ASAL+lice co-stimulation (ASAL/lice vs. PBS/no lice; 1878 up and 3120 down-regulated probes) confirmed partial mitigation of lice repressive effects on fundamental cellular processes and the activation of pathways involved in innate (e.g., neutrophil degranulation) and adaptive immunity (e.g., antibody formation), as well as endothelial cell migration. The qPCR analyses evidenced immune-relevant genes co-stimulated by ASAL and lice in an additive (e.g., mbl2b, bcl6) and synergistic (e.g., hampa, il4r) manner. These results provided insight on the physiological response of the skin of L. salmonis-infected salmon 24 h after ASAL stimulation, which revealed immunostimulatory properties by the bacterin with potential applications in anti-lice treatments for aquaculture. As a simulated co-infection model, the present study also serves as a source of candidate gene biomarkers for sea lice and bacterial co-infection.

Human skeletal muscle CD90+ fibro-adipogenic progenitors are associated with muscle degeneration in type 2 diabetic patients

Type 2 diabetes mellitus (T2DM) is associated with impaired skeletal muscle function and degeneration of the skeletal muscles. However, the mechanisms underlying the degeneration are not well described in human skeletal muscle. Here we show that skeletal muscle of T2DM patients exhibit degenerative remodeling of the extracellular matrix that is associated with a selective increase of a subpopulation of fibro-adipogenic progenitors (FAPs) marked by expression of THY1 (CD90)-the FAP^CD90+. We identify platelet-derived growth factor (PDGF) as a key FAP regulator, as it promotes proliferation and collagen production at the expense of adipogenesis. FAPs^CD90+ display a PDGF-mimetic phenotype, with high proliferative activity, clonogenicity, and production of extracellular matrix. FAP^CD90+ proliferation was reduced by in vitro treatment with metformin. Furthermore, metformin treatment reduced FAP content in T2DM patients. These data identify a PDGF-driven conversion of a subpopulation of FAPs as a key event in the fibrosis development in T2DM muscle.

Periostin in Allergy and Inflammation

Matricellular proteins are involved in the crosstalk between cells and their environment and thus play an important role in allergic and inflammatory reactions. Periostin, a matricellular protein, has several documented and multi-faceted roles in health and disease. It is differentially expressed, usually upregulated, in allergic conditions, a variety of inflammatory diseases as well as in cancer and contributes to the development and progression of these diseases. Periostin has also been shown to influence tissue remodelling, fibrosis, regeneration and repair. In allergic reactions periostin is involved in type 2 immunity and can be induced by IL-4 and IL-13 in bronchial cells. A variety of different allergic diseases, among them bronchial asthma and atopic dermatitis (AD), have been shown to be connected to periostin expression. Periostin is commonly expressed in fibroblasts and acts on epithelial cells as well as fibroblasts involving integrin and NF-κB signalling. Also direct signalling between periostin and immune cells has been reported. The deposition of periostin in inflamed, often fibrotic, tissues is further fuelling the inflammatory process. There is increasing evidence that periostin is also expressed by epithelial cells in several of the above-mentioned conditions as well as in cancer. Augmented periostin expression has also been associated with chronic inflammation such as in inflammatory bowel disease (IBD). Periostin can be expressed in a variety of different isoforms, whose functions have not been elucidated yet. This review will discuss potential functions of periostin and its different isoforms in allergy and inflammation.

Vascular Ehlers-Danlos Syndrome: Treatment of a Complex Abdominal Wound with Vitamin C and Mesenchymal Stromal Cells

ABSTRACT

Vascular Ehlers-Danlos syndrome (EDSv) can present with life-threatening surgical complications. The article describes the case of a patient with EDSv who developed total abdominal wound dehiscence and multiple enterocutaneous fistulas. Treatment with IV allogeneic mesenchymal stromal cells (MSCs) and high-dose vitamin C was trialed with success. Near-complete wound healing of the abdominal dehiscence with a 94% reduction in the size of the wound bed occurred. Maturation of the enterocutaneous fistulas also ensued.There is no current consensus on the management of large cutaneous wounds in EDSv. This article discusses the pathophysiology of wound healing with regard to nutrition requirements and growth factors with special reference to collagen deficits in EDSv. A potential therapy with IV vitamin C supplementation and MSCs is proposed following the patient's positive outcome. Medium-dose MSCs and high-dose IV vitamin C may offer significant benefits to complex and problematic wounds.

Evaluation of periostin levels in gingival crevicular fluid in association between coronary heart disease and chronic periodontitis

BACKGROUND

Periostin is a protein, which is essential for periodontal tissue integrity, development and maturity. The aim of this study was to evaluate the role of gingival crevicular fluid (GCF) periostin levels in the association between coronary heart disease (CHD) and chronic periodontitis (CP).

MATERIALS AND METHODS

This matched case-control study was conducted on 116 participants. The participants were matched for age, gender, and body mass index and divided into four groups as follows: (1) 29 patients with CHD and sever CP (CHD-CP), (2) 29 patients with CHD and without CP (CHD-H), (3) 29 patients without CHD and with sever CP (H-CP), and (4) 29 healthy participants (H-H). The GCF periostin was collected and evaluated using the enzyme-linked immunosorbent assay (ELASA). Finally, the data were analyzed by analysis of variance using the stata software. Significance was assigned at P < 0.05.

RESULTS

The results showed that there was a significant difference in the GCF periostin levels in the four groups (P < 0.05). Moreover, according to the results of the Bonferroni's test, differences in the mean periostin levels were significant (P < 0.001) between CHD-CP and CHD-H, CHD-CP and H-CP, CHD-CP and H-H, CHD-H and H-H, and also between H-CP and H-H.

CONCLUSION

The periostin levels reduced in the CHD patients, especially in the CHD-CP group. The findings reveal a probable role of periostin in the association between CHD and CP.

VDAC1 Silencing in Cancer Cells Leads to Metabolic Reprogramming That Modulates Tumor Microenvironment

Simple Summary

Tumors are comprised of proliferating cancer cells, and their microenvironment consists of the extracellular matrix, blood vessels, and a variety of tissue cells. The tumor microenvironment functions in cell growth, proliferation, migration, immunity, malignant transformation, and apoptosis. Understanding the molecular interactions between cancer cells and their microenvironment would facilitate the development of therapeutic strategies to disrupt these interactions and fight cancer. Here, we demonstrate that depleting the mitochondrial gatekeeper VDAC1 in human cancer cells in tumors led to metabolic reprogramming, inhibited tumor growth, and disrupted tumor–host interactions. A next-generation sequencing analysis of human lung cell-derived tumors expressing or depleted of VDAC1 allows distinguishing genes of human or murine origin, thus enabling the separation of the bidirectional cross-talk between malignant cells and the tumor microenvironment. A battery of human cancer cell and mouse genes associated with tumor microenvironment formation and remodeling were altered. The results point to VDAC1 as a novel target for both inhibiting tumor growth and modulating the tumor microenvironment, thus influencing cancer progression, migration, and invasion.

Abstract

The tumor microenvironment (TME) plays an important role in cell growth, proliferation, migration, immunity, malignant transformation, and apoptosis. Thus, better insight into tumor–host interactions is required. Most of these processes involve the metabolic reprogramming of cells. Here, we focused on this reprogramming in cancerous cells and its effect on the TME. A major limitation in the study of tumor–host interactions is the difficulty in separating cancerous from non-cancerous signaling pathways within a tumor. Our strategy involved specifically silencing the expression of VDAC1 in the mitochondria of human-derived A549 lung cancer xenografts in mice, but not in the mouse-derived cells of the TME. Next-generation sequencing (NGS) analysis allows distinguishing the human or mouse origin of genes, thus enabling the separation of the bidirectional cross-talk between the TME and malignant cells. We demonstrate that depleting VDAC1 in cancer cells led to metabolic reprogramming, tumor regression, and the disruption of tumor–host interactions. This was reflected in the altered expression of a battery of genes associated with TME, including those involved in extracellular matrix organization and structure, matrix-related peptidases, angiogenesis, intercellular interacting proteins, integrins, and growth factors associated with stromal activities. We show that metabolic rewiring upon mitochondrial VDAC1 silencing in cancer cells affected several components of the TME, such as structural protein matrix metalloproteinases and Lox, and elicited a stromal response resembling the reaction to a foreign body in wound healing. As tumor progression requires a cooperative interplay between the host and cancer cells, and the ECM is intensively remodeled during cancer progression, VDAC1 depletion induced metabolic reprogramming that targeted both tumor cells and resulted in the alteration of the whole spectrum of TME-related genes, affecting the reciprocal feedback between ECM molecules, host cells, and cancer cells. Thus, VDAC1 depletion using si-VDAC1 represents therapeutic potential, inhibiting cancer cell proliferation and also inducing the modulation of TME components, which influences cancer progression, migration, and invasion.

Silencing periostin inhibits myofibroblast transdifferentiation of fibrotic buccal mucosal fibroblasts

BACKGROUND/PURPOSE

Oral submucous fibrosis (OSF) a well-recognized oral premalignant disorder. Several studies have demonstrated that periostin, a matricellular protein, is involved in the development and pathogenesis of fibrosis diseases. Nevertheless, the contribution of periostin in OSF remains to be uncovered. The purpose of the study was to illustrate the functional role of periostin involved in OSF pathogenesis.

METHODS

RNA-sequencing was employed to screen for differentially expressed genes in normal and OSF tissues. Validation of the upregulation of periostin in OSF specimens and fibrotic buccal mucosal fibroblasts (fBMFs) was conducted by qRT-PCR. The correlation of the gene expression of periostin and various fibrosis markers was analyzed. In addition, the functional role of periostin in myofibroblast features was tested using collagen gel contraction and transwell migration assays.

RESULTS

We observed overexpression of periostin in OSF specimens using RNA-sequencing and confirmed its upregulation in OSF tissues and patient-derived fBMFs. Besides, there was a positive relationship between the expression of periostin and several fibrosis-associated markers, including ACTA2 (α-smooth muscle actin; α-SMA), COL1A1 (type 1 collagen α1 chain), TGFB1 (TGF-β1), and FN1 (fibronectin). Furthermore, we examined the effect of silencing periostin on the maintenance of myofibroblast characteristics and showed that knockdown of periostin suppressed the expression of α-SMA. Also, inhibition of periostin markedly downregulated the myofibroblast activities (collagen gel contraction and migration capacities).

CONCLUSION

Our results indicate the aberrant expression of periostin in OSF tissues and myofibroblasts. Moreover, the expression of periostin is positively associated with fibrosis markers, and repression of periostin may be a promising direction to alleviate the progression of OSF.

Lipofilling in Breast Oncological Surgery: A Safe Opportunity or Risk for Cancer Recurrence?

Lipofilling (LF) is a largely employed technique in reconstructive and esthetic breast surgery. Over the years, it has demonstrated to be extremely useful for treatment of soft tissue defects after demolitive or conservative breast cancer surgery and different procedures have been developed to improve the survival of transplanted fat graft. The regenerative potential of LF is attributed to the multipotent stem cells found in large quantity in adipose tissue. However, a growing body of pre-clinical evidence shows that adipocytes and adipose-derived stromal cells may have pro-tumorigenic potential. Despite no clear indication from clinical studies has demonstrated an increased risk of cancer recurrence upon LF, these observations challenge the oncologic safety of the procedure. This review aims to provide an updated overview of both the clinical and the pre-clinical indications to the suitability and safety of LF in breast oncological surgery. Cellular and molecular players in the crosstalk between adipose tissue and cancer are described, and heterogeneous contradictory results are discussed, highlighting that important issues still remain to be solved to get a clear understanding of LF safety in breast cancer patients.

Fasciclin-Like Arabinogalactan-Protein 16 (FLA16) Is Required for Stem Development in Arabidopsis

The predominant Fascilin 1 (FAS1)-containing proteins in plants belong to the Fasciclin-Like Arabinogalactan-protein (FLA) family of extracellular glycoproteins. In addition to FAS1 domains, these multi-domain FLA proteins contain glycomotif regions predicted to direct addition of large arabinogalactan (AG) glycans and many contain signal sequences for addition of a glycosylphosphatidylinositol (GPI)-anchor to tether them to the plasma membrane. FLAs are proposed to play both structural and signaling functions by forming a range of interactions in the plant extracellular matrix, similar to FAS1-containing proteins in animals. FLA group B members contain two FAS1 domains and are not predicted to be GPI-anchored. None of the group B members have been functionally characterized or their sub-cellular location resolved, limiting understanding of their function. We investigated the group B FLA16 in Arabidopsis that is predominantly expressed in inflorescence tissues. FLA16 is the most highly expressed FLA in the stem after Group A members FLA11 and FLA12 that are stem specific. A FLA16-YFP fusion protein driven by the endogenous putative FLA16 promoter in wild type background showed expression in cells with secondary cell walls, and FLA16 displayed characteristics of cell wall glycoproteins with moderate glycosylation. Investigation of a fla16 mutant showed loss of FLA16 leads to reduced stem length and altered biomechanical properties, likely as a result of reduced levels of cellulose. Immuno-labeling indicated support for FLA16 location to the plasma-membrane and (apoplastic) cell wall of interfascicular stem fiber cells. Together these results indicate FLA16, a two-FAS1 domain FLAs, plays a role in plant secondary cell wall synthesis and function.

Immunotherapy for Infarcts: In Vivo Postinfarction Macrophage Modulation Using Intramyocardial Microparticle Delivery of Map4k4 Small Interfering RNA

The myeloid cells infiltrating the heart early after acute myocardial infarction elaborate a secretome that largely orchestrates subsequent ventricular wall repair. Regulating this innate immune response could be a means to improve infarct healing. To pilot this concept, we utilized (β1,3-d-) glucan-encapsulated small interfering RNA (siRNA)-containing particles (GeRPs), targeting mononuclear phagocytes, delivered to mice as a one-time intramyocardial injection immediately after acute infarction. Findings demonstrated that cardiac macrophages phagocytosed GeRPs in vivo and had little systemic dissemination, thus providing a means to deliver local therapeutics. Acute infarcts were then injected in vivo with phosphate-buffered saline (PBS; vehicle) or GeRPs loaded with siRNA to Map4k4, and excised hearts were examined at 3 and 7 days by quantitative polymerase chain reaction, flow cytometry, and histology. Compared with infarcted PBS-treated hearts, hearts with intrainfarct injections of siRNA-loaded GeRPs exhibited 69–89% reductions in transcripts for Map4k4 (mitogen-activated protein kinase kinase kinase kinase 4), interleukin (IL)-1β, and tumor necrosis factor α at 3 days. Expression of other factors relevant to matrix remodeling—monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases, hyaluronan synthases, matricellular proteins, and profibrotic factors transforming growth factor beta (TGF-β), and connective tissue growth factor (CTGF)—were also decreased. Most effects peaked at 3 days, but, in some instances (Map4k4, IL-1β, TGF-β, CTGF, versican, and periostin), suppression persisted to 7 days. Thus, direct intramyocardial GeRP injection could serve as a novel and clinically translatable platform for in vivo RNA delivery to intracardiac macrophages for local and selective immunomodulation of the infarct microenvironment.

NF-κB activation persists into the remodeling phase of tendon healing and promotes myofibroblast survival

Although inflammation is necessary during the early phases of tissue repair, persistent inflammation contributes to fibrosis. Acute tendon injuries often heal through a fibrotic mechanism, which impedes regeneration and functional recovery. Because inflammation mediated by nuclear factor κB (NF-κB) signaling is implicated in this process, we examined the spatial, temporal, and cell type-specific activation profile of canonical NF-κB signaling during tendon healing. NF-κB signaling was maintained through all phases of tendon healing in mice, including the remodeling phase, and tenocytes and myofibroblasts from the Scleraxis (Scx) lineage were the predominant populations that retained NF-κB activation into the late stages of repair. We confirmed persistent NF-κB activation in myofibroblasts in human tendon scar tissue. Deleting the canonical NF-κB kinase, IKKβ, in Scx-lineage cells in mice increased apoptosis and the deposition of the matrix protein periostin during the late stages of tendon repair, suggesting that persistent NF-κB signaling may facilitate myofibroblast survival and fibrotic progression. Consistent with this, myofibroblasts in human tendon scar samples displayed enhanced prosurvival signaling compared to control tissue. Together, these data suggest that NF-κB may contribute to fibrotic tendon healing through both inflammation-dependent and inflammation-independent functions, such as NF-κB-mediated cell survival.

The Interaction between Mitochondrial Oxidative Stress and Gut Microbiota in the Cardiometabolic Consequences in Diet-Induced Obese Rats

BACKGROUND

The objective of this study is to determine the role of mitochondrial oxidative stress in the dysbiosis associated with a high fat diet in rats. In addition, the impact of gut microbiota (GM) in the cardiometabolic consequences of diet-induced obesity in rats has been evaluated.

METHODS

Male Wistar rats were fed either a high fat diet (HFD) or a control (CT) one for 6 weeks. At the third week, one-half of the animals of each group were treated with the mitochondrial antioxidant MitoTempo (MT; 0.7 mgKg^-1day^-1 i.p).

RESULTS

Animals fed an HFD showed a lower microbiota evenness and diversity in comparison to CT rats. This dysbiosis is characterized by a decrease in Firmicutes/Bacteroidetes ratio and relevant changes at family and genera compared with the CT group. This was accompanied by a reduction in colonic mucin-secreting goblet cells. These changes were reversed by MT treatment. The abundance of certain genera could also be relevant in the metabolic consequences of obesity, as well as in the occurrence of cardiac fibrosis associated with obesity.

CONCLUSIONS

These results support an interaction between GM and mitochondrial oxidative stress and its relation with development of cardiac fibrosis, suggesting new approaches in the management of obesity-related cardiometabolic consequences.

Emerging Roles of Matricellular Proteins in Systemic Sclerosis

Systemic sclerosis is a rare chronic heterogenous disease that involves inflammation and vasculopathy, and converges in end-stage development of multisystem tissue fibrosis. The loss of tight spatial distribution and temporal expression of proteins in the extracellular matrix (ECM) leads to progressive organ stiffening, which is a hallmark of fibrotic disease. A group of nonstructural matrix proteins, known as matricellular proteins (MCPs) are implicated in dysregulated processes that drive fibrosis such as ECM remodeling and various cellular behaviors. Accordingly, MCPs have been described in the context of fibrosis in sclerosis (SSc) as predictive disease biomarkers and regulators of ECM synthesis, with promising therapeutic potential. In this present review, an informative summary of major MCPs is presented highlighting their clear correlations to SSc- fibrosis.

Activin-mediated alterations of the fibroblast transcriptome and matrisome control the biomechanical properties of skin wounds

Matrix deposition is essential for wound repair, but when excessive, leads to hypertrophic scars and fibrosis. The factors that control matrix deposition in skin wounds have only partially been identified and the consequences of matrix alterations for the mechanical properties of wounds are largely unknown. Here, we report how a single diffusible factor, activin A, affects the healing process across scales. Bioinformatics analysis of wound fibroblast transcriptome data combined with biochemical and histopathological analyses of wounds and functional in vitro studies identify that activin promotes pro-fibrotic gene expression signatures and processes, including glycoprotein and proteoglycan biosynthesis, collagen deposition, and altered collagen cross-linking. As a consequence, activin strongly reduces the wound and scar deformability, as identified by a non-invasive in vivo method for biomechanical analysis. These results provide mechanistic insight into the roles of activin in wound repair and fibrosis and identify the functional consequences of alterations in the wound matrisome at the biomechanical level.

The relationship between histopathology, gene expression, and biochemical and mechanical properties of wounds is largely unknown. Here, the authors show that activin A alters wound healing at multiple levels by promoting pro-fibrotic gene expression and matrix deposition, thereby affecting biomechanical properties of skin wounds.

Evolution of Sequence-Diverse Disordered Regions in a Protein Family: Order within the Chaos

Approaches for studying the evolution of globular proteins are now well established yet are unsuitable for disordered sequences. Our understanding of the evolution of proteins containing disordered regions therefore lags that of globular proteins, limiting our capacity to estimate their evolutionary history, classify paralogs, and identify potential sequence–function relationships. Here, we overcome these limitations by using new analytical approaches that project representations of sequence space to dissect the evolution of proteins with both ordered and disordered regions, and the correlated changes between these. We use the fasciclin-like arabinogalactan proteins (FLAs) as a model family, since they contain a variable number of globular fasciclin domains as well as several distinct types of disordered regions: proline (Pro)-rich arabinogalactan (AG) regions and longer Pro-depleted regions.

Sequence space projections of fasciclin domains from 2019 FLAs from 78 species identified distinct clusters corresponding to different types of fasciclin domains. Clusters can be similarly identified in the seemingly random Pro-rich AG and Pro-depleted disordered regions. Sequence features of the globular and disordered regions clearly correlate with one another, implying coevolution of these distinct regions, as well as with the N-linked and O-linked glycosylation motifs. We reconstruct the overall evolutionary history of the FLAs, annotated with the changing domain architectures, glycosylation motifs, number and length of AG regions, and disordered region sequence features. Mapping these features onto the functionally characterized FLAs therefore enables their sequence–function relationships to be interrogated. These findings will inform research on the abundant disordered regions in protein families from all kingdoms of life.

Extracellular matrix, integrins, and focal adhesion signaling in polycystic kidney disease

In autosomal dominant polycystic kidney disease (ADPKD), the inexorable growth of numerous fluid-filled cysts leads to massively enlarged kidneys, renal interstitial damage, inflammation, and fibrosis, and progressive decline in kidney function. It has long been recognized that interstitial fibrosis is the most important manifestation associated with end-stage renal disease; however, the role of abnormal extracellular matrix (ECM) production on ADPKD pathogenesis is not fully understood. Early evidence showed that cysts in end-stage human ADPKD kidneys had thickened and extensively laminated cellular basement membranes, and abnormal regulation of gene expression of several basement membrane components, including collagens, laminins, and proteoglycans by cyst epithelial cells. These basement membrane changes were also observed in dilated tubules and small cysts of early ADPKD kidneys, indicating that ECM alterations were early features of cyst development. Renal cystic cells were also found to overexpress several integrins and their ligands, including ECM structural components and soluble matricellular proteins. ECM ligands binding to integrins stimulate focal adhesion formation and can promote cell attachment and migration. Abnormal expression of laminin-332 (laminin-5) and its receptor α₆β₄ stimulated cyst epithelial cell proliferation; and mice that lacked laminin α₅, a component of laminin-511 normally expressed by renal tubules, had an overexpression of laminin-332 that was associated with renal cyst formation. Periostin, a matricellular protein that binds α_Vβ₃- and α_Vβ₅-integrins, was found to be highly overexpressed in the kidneys of ADPKD and autosomal recessive PKD patients, and several rodent models of PKD. α_Vβ₃-integrin is also overexpressed by cystic epithelial cells, and the binding of periostin to α_Vβ₃-integrin activates the integrin-linked kinase and downstream signal transduction pathways involved in tissue repair promoting cyst growth, ECM synthesis, and tissue fibrosis. This chapter reviews the roles of the ECM, integrins, and focal adhesion signaling in cyst growth and fibrosis in PKD.

Assessing the unified airway hypothesis in children via transcriptional profiling of the airway epithelium

BACKGROUND

Emerging evidence suggests that disease vulnerability is expressed throughout the airways, the so-called unified airway hypothesis, but the evidence to support this is predominantly indirect.

OBJECTIVES

We sought to establish the transcriptomic profiles of the upper and lower airways and determine their level of similarity irrespective of airway symptoms (wheeze) and allergy.

METHODS

We performed RNA sequencing on upper and lower airway epithelial cells from 63 children with or without wheeze and accompanying atopy, using differential gene expression and gene coexpression analyses to determine transcriptional similarity.

RESULTS

We observed approximately 91% homology in the expressed genes between the 2 sites. When coexpressed genes were grouped into modules relating to biological functions, all were found to be conserved between the 2 regions, resulting in a consensus network containing 16 modules associated with ribosomal function, metabolism, gene expression, mitochondrial activity, and antiviral responses through IFN activity. Although symptom-associated gene expression changes were more prominent in the lower airway, they were reflected in nasal epithelium and included IL-1 receptor like 1, prostaglandin-endoperoxide synthase 1, CCL26, and periostin. Through network analysis we identified a cluster of coexpressed genes associated with atopic wheeze in the lower airway, which could equally distinguish atopic and nonatopic phenotypes in upper airway samples.

CONCLUSIONS

We show that the upper and lower airways are significantly conserved in their transcriptional composition, and that variations associated with disease are present in both nasal and tracheal epithelium. Findings from this study supporting a unified airway imply that clinical insight regarding the lower airway in health and disease can be gained from studying the nasal epithelium.

JNK Signaling as a Key Modulator of Soft Connective Tissue Physiology, Pathology, and Healing

In healthy individuals, the healing of soft tissues such as skin after pathological insult or post injury follows a relatively predictable and defined series of cell and molecular processes to restore tissue architecture and function(s). Healing progresses through the phases of hemostasis, inflammation, proliferation, remodeling, and concomitant with re-epithelialization restores barrier function. Soft tissue healing is achieved through the spatiotemporal interplay of multiple different cell types including neutrophils, monocytes/macrophages, fibroblasts, endothelial cells/pericytes, and keratinocytes. Expressed in most cell types, c-Jun N-terminal kinases (JNK) are signaling molecules associated with the regulation of several cellular processes involved in soft tissue wound healing and in response to cellular stress. A member of the mitogen-activated protein kinase family (MAPK), JNKs have been implicated in the regulation of inflammatory cell phenotype, as well as fibroblast, stem/progenitor cell, and epithelial cell biology. In this review, we discuss our understanding of JNKs in the regulation of cell behaviors related to tissue injury, pathology, and wound healing of soft tissues. Using models as diverse as Drosophila, mice, rats, as well as human tissues, research is now defining important, but sometimes conflicting roles for JNKs in the regulation of multiple molecular processes in multiple different cell types central to wound healing processes. In this review, we focus specifically on the role of JNKs in the regulation of cell behavior in the healing of skin, cornea, tendon, gingiva, and dental pulp tissues. We conclude that while parallels can be drawn between some JNK activities and the control of cell behavior in healing, the roles of JNK can also be very specific modes of action depending on the tissue and the phase of healing.

Characterization of Matricellular Protein Expression Signatures in Mechanistically Diverse Mouse Models of Kidney Injury

Fibrosis is the most common pathophysiological manifestation of Chronic Kidney Disease (CKD). It is defined as excessive deposition of extracellular matrix (ECM) proteins. Embedded within the ECM are a family of proteins called Matricellular Proteins (MCPs), which are typically expressed during chronic pathologies for ECM processing. As such, identifying potential MCPs in the pathological secretome of a damaged kidney could serve as diagnostic/therapeutic targets of fibrosis. Using published RNA-Seq data from two kidney injury mouse models of different etiologies, Folic Acid (FA) and Unilateral Ureteral Obstruction (UUO), we compared and contrasted the expression profile of various members from well-known MCP families during the Acute and Fibrotic injury phases. As a result, we identified common and distinct MCP expression signatures between both injury models. Bioinformatic analysis of their differentially expressed MCP genes revealed similar top annotation clusters from Molecular Function and Biological Process networks, which are those commonly involved in fibrosis. Using kidney lysates from FA- and UUO-injured mice, we selected MCP genes from our candidate list to confirm mRNA expression by Western Blot, which correlated with injury progression. Understanding the expressions of MCPs will provide important insight into the processes of kidney repair, and may validate MCPs as biomarkers and/or therapeutic targets of CKD.

Evaluation of periostin level for predicting severity and chronicity of childhood atopic dermatitis

Introduction

Periostin has some effects on the pathogenesis of atopic dermatitis (AD) via release of pro-inflammatory cytokines and chemokines from activated keratinocytes and it is related to chronicity of skin lesions.

Aim

To evaluate the relationship between plasma periostin levels and severity and chronicity of AD in children.

Material and methods

The study population consisted of 29 children with atopic dermatitis without concomitant allergic disease such as asthma or allergic rhinitis and 31 healthy controls. Data of demographic features, serum eosinophil, total IgE and skin prick test results were collected through the patient's medical records. The severity of the disease was assessed by the SCORAD index. Serum periostin levels were measured with a human periostin ELISA kit.

Results

The mean ages of the AD patients and the control group participants were 80.7 ±52.8 and 90.3 ±41.6 months, respectively. Mean plasma periostin levels were 63.0 ±19.0 ng/ml in AD patients, and 23.6 ±7.3 in healthy controls, and there was a statistically significant difference between the two groups (p = 0.001). Plasma periostin level did not vary according to total IgE or serum eosinophil count (p > 0.05). Age of onset and duration of symptoms also were not correlated with plasma periostin levels. Although there was a positive relationship between plasma periostin level and the SCORAD index of patients, it was not statistically significant (r = 0.19, p > 0.05).

Conclusions

This study showed that plasma periostin levels were increased in children with atopic dermatitis. Periostin may have a partial role in the pathogenesis of atopic dermatitis, but it is not associated with severity or chronicity in children with atopic dermatitis.

Evidence of Cardiovascular Calcification and Fibrosis in Pseudoxanthoma Elasticum Mouse Models Subjected to DOCA-Salt Hypertension

Pseudoxanthoma Elasticum (PXE) is a rare disorder characterized by fragmentation and progressive calcification of elastic fibres in connective tissues. Although arterial hypertension (AHT) has been reported in PXE patients, its impact on pathological manifestations has as yet been unexplored. We investigated the consequences of experimental AHT on Abcc6−/− PXE mouse models. Experimental AHT was induced by deoxycorticosterone acetate (DOCA-salt) in uni-nephrectomised mice. Blood pressure (BP) and vascular reactivity were monitored using tail-cuff plethysmography and myography respectively. Calcium content and fibrosis were assessed using colorimetry, Von Kossa and Sirius red staining respectively. The gene expression implicated in vascular biology was measured using quantitative polymerase chain reaction. DOCA-salt induced a matching rise in BP in Abcc6−/− and WT mice. Aortic ring contraction and relaxation in vitro were comparable. Calcium accumulated in the hearts of hypertensive Abcc6−/− mice along with significant fibrosis in the myocardium and aorta by contrast with the WT mice. In hypertensive Abcc6−/− mouse aortas, these results were corroborated by gene expression patterns favouring calcification, fibrosis and extracellular matrix remodelling. Abcc6 loss-of-function is associated with greater cardiovascular calcification and fibrosis in mice subjected to DOCA-Salt hypertension. These results suggest likely cardiovascular deterioration in PXE patients with AHT, necessitating diligent BP monitoring.

Periostin-expressing cell-specific transforming growth factor-β inhibition in pulmonary artery prevents pulmonary arterial hypertension

Transforming growth factor beta (TGF-β) has been shown to play a critical role in pathogenesis of pulmonary arterial hypertension (PAH) although the precise role of TGF-β signaling remains uncertain. A recent report has shown that periostin (Pn) is one of the most upregulated proteins in human PAH lung compared with healthy lungs. We established type I TGF-β receptor knockout mice specifically with Pn expressing cell (Pn-Cre/Tgfb1fl/fl mice). Increases in PA pressure and pulmonary artery muscularization were induced by hypoxia of 10% oxygen for 4 weeks. Lung Pn expression was markedly induced by 4 week-hypoxia. Pn-Cre/Tgfb1fl/fl mice showed lower right ventricular pressure elevation, inhibition of PA medial thickening. Fluorescent co-immunostaining showed that Smad3 activation in Pn expressing cell is attenuated. These results suggest that TGF-β signaling in Pn expressing cell may have an important role in the pathogenesis of PAH by controlling medial thickening.

Cellular and Molecular Mechanisms in the Pathogenesis of Classical, Vascular, and Hypermobile Ehlers‒Danlos Syndromes

The Ehlers‒Danlos syndromes (EDS) constitute a heterogenous group of connective tissue disorders characterized by joint hypermobility, skin abnormalities, and vascular fragility. The latest nosology recognizes 13 types caused by pathogenic variants in genes encoding collagens and other molecules involved in collagen processing and extracellular matrix (ECM) biology. Classical (cEDS), vascular (vEDS), and hypermobile (hEDS) EDS are the most frequent types. cEDS and vEDS are caused respectively by defects in collagen V and collagen III, whereas the molecular basis of hEDS is unknown. For these disorders, the molecular pathology remains poorly studied. Herein, we review, expand, and compare our previous transcriptome and protein studies on dermal fibroblasts from cEDS, vEDS, and hEDS patients, offering insights and perspectives in their molecular mechanisms. These cells, though sharing a pathological ECM remodeling, show differences in the underlying pathomechanisms. In cEDS and vEDS fibroblasts, key processes such as collagen biosynthesis/processing, protein folding quality control, endoplasmic reticulum homeostasis, autophagy, and wound healing are perturbed. In hEDS cells, gene expression changes related to cell-matrix interactions, inflammatory/pain responses, and acquisition of an in vitro pro-inflammatory myofibroblast-like phenotype may contribute to the complex pathogenesis of the disorder. Finally, emerging findings from miRNA profiling of hEDS fibroblasts are discussed to add some novel biological aspects about hEDS etiopathogenesis.