Differential expression of tenascin in the skin during hapten-induced dermatitis

Proof of Concept Study for Increasing Tenascin-C-Targeted Drug Delivery to Tumors Previously Subjected to Therapy: X-Irradiation Increases Tumor Uptake

Simple Summary

We hypothesized that an agent recognizing a specific factor, which is involved in tissue injury repair, could achieve the goal of delivering an additional antitumor agent to tumors during tissue repair after initial anticancer therapy. To demonstrate our concept, the present study employed tenascin-C (TNC) as a target molecule and radiation as initial therapy. Increased TNC expression was observed in tumors after radiation exposure in a pancreatic cancer mouse model. Of our three anti-TNC antibodies, the antibody 3–6 showed statistically significant higher tumor uptake compared with non-irradiated tumors in the by biodistribution and single-photon emission computed tomography with computed tomography studies. This finding strongly supports our concept. Our proposed therapeutic strategy could result in better outcomes for patients with treatment-refractory cancer.

Abstract

In treatment-refractory cancers, tumor tissues damaged by therapy initiate the repair response; therefore, tumor tissues must be exposed to an additional burden before successful repair. We hypothesized that an agent recognizing a molecule that responds to anticancer treatment-induced tissue injury could deliver an additional antitumor agent including a radionuclide to damaged cancer tissues during repair. We selected the extracellular matrix glycoprotein tenascin-C (TNC) as such a molecule, and three antibodies recognizing human and murine TNC were employed to evaluate X-irradiation-induced changes in TNC uptake by subcutaneous tumors. TNC expression was assessed by immunohistochemical staining of BxPC-3 tumors treated with or without X-irradiation (30 Gy) for 7 days. Antibodies against TNC (3–6, 12–2–7, TDEAR) and a control antibody were radiolabeled with ¹¹¹In and injected into nude mice having BxPC-3 tumors 7 days after X-irradiation, and temporal uptake was monitored for an additional 4 days by biodistribution and single-photon emission computed tomography with computed tomography (SPECT/CT) studies. Intratumoral distribution was analyzed by autoradiography. The immunohistochemical signal for TNC expression was faint in nontreated tumors but increased and expanded with time until day 7 after X-irradiation. Biodistribution studies revealed increased tumor uptake of all three ¹¹¹In-labeled antibodies and the control antibody. However, a statistically significant increase in uptake was evident only for ¹¹¹In-labeled 3–6 (35% injected dose (ID)/g for 30 Gy vs. 15% ID/g for 0 Gy at day 1, p < 0.01), whereas limited changes in ¹¹¹In-labeled TDEAR2, 12–2–27, and control antibody were observed (several % ID/g for 0 and 30 Gy). Serial SPECT/CT imaging with ¹¹¹In-labeled 3–6 or control antibody provided consistent results. Autoradiography revealed noticeably stronger signals in irradiated tumors injected with ¹¹¹In-labeled 3–6 compared with each of the nonirradiated tumors and the control antibody. The signals were observed in TNC-expressing stroma. Markedly increased uptake of ¹¹¹In-labeled 3–6 in irradiated tumors supports our concept that an agent, such as an antibody, that recognizes a molecule involved in tissue injury repair, such as TNC, could enhance drug delivery to tumor tissues that have undergone therapy. The combination of antibody 3–6 coupled to a tumoricidal drug and conventional therapy has the potential to achieve better outcomes for patients with refractory cancer.

Matrix-Targeting Immunotherapy Controls Tumor Growth and Spread by Switching Macrophage Phenotype

The interplay between cancer cells and immune cells is a key determinant of tumor survival. Here, we uncovered how tumors exploit the immunomodulatory properties of the extracellular matrix to create a microenvironment that enables their escape from immune surveillance. Using orthotopic grafting of mammary tumor cells in immunocompetent mice and autochthonous models of breast cancer, we discovered how tenascin-C, a matrix molecule absent from most healthy adult tissues but expressed at high levels and associated with poor patient prognosis in many solid cancers, controls the immune status of the tumor microenvironment. We found that, although host-derived tenascin-C promoted immunity via recruitment of proinflammatory, antitumoral macrophages, tumor-derived tenascin-C subverted host defense by polarizing tumor-associated macrophages toward a pathogenic, immune-suppressive phenotype. Therapeutic monoclonal antibodies that blocked tenascin-C activation of Toll-like receptor 4 reversed this phenotypic switch in vitro and reduced tumor growth and lung metastasis in vivo, providing enhanced benefit in combination with anti-PD-L1 over either treatment alone. Combined tenascin-C:macrophage gene-expression signatures delineated a significant survival benefit in people with breast cancer. These data revealed a new approach to targeting tumor-specific macrophage polarization that may be effective in controlling the growth and spread of breast tumors.

Core-Shell Nanofibrous Scaffolds for Repair of Meniscus Tears

Electrospinning is an attractive method of fabricating nanofibers that replicate the ultrastructure of the human meniscus. However, it is challenging to approximate the mechanical properties of meniscal tissue while maintaining the biocompatibility of collagen fibers. Our objective was to determine if functionalizing polylactic acid (PLA) nanofibers with collagen would enhance their biocompatibility. We therefore used coaxial electrospinning to generate core-shell nanofibers with a core of PLA for mechanical strength and a shell of collagen to enhance cell attachment and matrix synthesis. We characterized the nanostructure of the engineered scaffolds and measured the hydrophilic and mechanical properties. We assessed the performance of human meniscal cells seeded on coaxial electrospun scaffolds to produce meniscal tissue by gene expression and histology. Finally, we investigated whether these cell-seeded scaffolds could repair surgical tears created ex vivo in avascular meniscal explants. Histology, immunohistochemistry, and mechanical testing of ex vivo repair provided evidence of neotissue that was significantly better integrated with the native tissue than with the acellular coaxial electrospun scaffolds. Human meniscal cell-seeded coaxial electrospun scaffolds may have potential in enhancing repair of avascular meniscus tears. Impact Statement The success of any tissue-engineered meniscus graft relies on its ability to mimic native three-dimensional microstructure, support cell growth, produce tissue-specific matrix, and enhance graft integration into the repair site. Polylactic acid scaffolds possess the desired mechanical properties, whereas collagen scaffolds induce better cell attachment and enhanced tissue regeneration. We therefore fabricated nanofibrous scaffolds that combined the properties of two biomaterials. These novel coaxial scaffolds more closely emulated the structure, mechanical properties, and biochemical composition of native meniscal tissue. Our findings of meniscogenic tissue generation and integration in meniscus defects have the potential to be translated to clinical use.

Meniscal Tissue Engineering Using Aligned Collagen Fibrous Scaffolds: Comparison of Different Human Cell Sources

Hydrogel and electrospun scaffold materials support cell attachment and neotissue development and can be tuned to structurally and mechanically resemble native extracellular matrix by altering either electrospun fiber or hydrogel properties. In this study, we examined meniscus tissue generation from different human cell sources including meniscus cells derived from vascular and avascular regions, human bone marrow-derived mesenchymal stem cells, synovial cells, and cells from the infrapatellar fat pad (IPFP). All cells were seeded onto aligned electrospun collagen type I scaffolds and were optionally encapsulated in a tricomponent hydrogel. Single or multilayered constructs were generated and cultivated in defined medium with selected growth factors for 2 weeks. Cell viability, cell morphology, and gene-expression profiles were monitored using confocal microscopy, scanning electron microscopy, and quantitative polymerase chain reaction (qPCR), respectively. Multilayered constructs were examined with histology, immunohistochemistry, qPCR, and for tensile mechanical properties. For all cell types, TGFβ1 and TGFβ3 treatment increased COL1A1, COMP, Tenascin C (TNC), and Scleraxis (SCX) gene expression and deposition of collagen type I protein. IPFP cells generated meniscus-like tissues with higher meniscogenic gene expression, mechanical properties, and better cell distribution compared to other cell types studied. We show proof of concept that electrospun collagen scaffolds support neotissue formation and IPFP cells have potential for use in cell-based meniscus regeneration strategies.

Staphylococcal superantigen-like protein 8 (SSL8) binds to tenascin C and inhibits tenascin C-fibronectin interaction and cell motility of keratinocytes

Staphylococcal superantigen-like protein (SSL), a family of exotoxins composed of 14 SSLs, exhibits no superantigenic activity despite of its structural similarity with superantigens. Several SSLs have been revealed to bind to host immune molecules such as IgA, IgG, complement and cell surface molecules expressed on immune cells, but the physiological function of SSL family has not been fully identified. In this study we attempted to isolate host target proteins of SSLs from human breast milk using SSLs-conjugated Sepharose. SSL8-conjugated Sepharose specifically recovered tenascin C (TNC), a multimodular and multifunctional extracellular matrix protein. Pull down analysis using SSL8-conjugated Sepharose and recombinant truncated fragments of TNC revealed that SSL8 interacts with fibronectin (FN) type III repeats 1-5 of TNC. The interaction of TNC with immobilized FN was attenuated, the scratch wound closure by HaCaT human keratinocytes was delayed and the inhibition of cell spreading on FN by TNC was recovered in the presence of SSL8. These findings suggest that SSL8 binds to TNC, thereby inhibits the TNC-FN interaction and motility of keratinocytes. The present study added a novel role of SSL family protein as an interrupting molecule against the function of extracellular matrix.

Size control of decorin dermatan sulfate during remodeling of collagen fibrils in healing skin

Recently it has been reported that the molecular size of decorin dermatan sulfate (DS) was increased in healing skin after hapten application and that the elongated DS was distributed in enlarged interfibrillar space among thin collagen fibrils in situ. Here we show that such modulation of the length of decorin DS is temporary. Although the size of decorin DS was evidently increased on day 15, it decreased to almost normal size on day 35 when the altered disaccharide composition of DS was also recovered. Electron microscopic observation revealed that elongated decorin DS was localized among thin collagen fibrils packed loosely in hapten-treated skin on day 15. In contrast, decorin DS of normal size was distributed among thick collagen fibrils packed tightly on day 35. These results suggest that size control of decorin DS plays important roles in organization of collagen fibrils into bundles by regulating interfibrillar space in healing skin, particularly in maturation of collagen fibrils through shortening of decorin DS in later stages of healing.

Tenascin-C expression and splice variant in habu snake venom-induced glomerulonephritis

Extracellular matrix glycoprotein tenascin-C (TNC) expression is up-regulated in tissue remodeling processes such as tumorigenesis and wound healing. Mouse tenascin-C contains six alternatively spliced domains (A1, A2, A4, B, C, and D) between the fifth and the sixth type III fibronectin domains, which generate large numbers of TNC isoforms. To study TNC isoform variability of wound healing in mice, we induced glomerulonephritis by using Habu snake venom (HSV) and examined alternatively spliced regions by the reverse transcription polymerase chain reaction (RT-PCR) technique. RT-PCR products were separated into seven bands in both healthy and diseased kidneys. Among the seven bands, those containing one or five alternatively spliced domains were mainly up-regulated from 2 days to 1 week after HSV injection. Southern blotting revealed that only domain-D detected all six bands in both healthy and diseased kidneys. Furthermore, only the domain-C transcriptional level did not show an obvious change in progress following HSV injection. These results suggested that (a) the isoforms containing one or five alternatively spliced domains play important roles in the healing process of glomerulonephritis, (b) domain-D is particularly significant in kidney, and (c) domain-C may not play an important role in the healing process of HSV-induced glomerulonephritis.

PDGF receptor-alpha deficiency in glomerular mesangial cells of tenascin-C knockout mice

Tenascin-C (TNC) knockout (TNKO) mice showed reduced proliferation of mesangial cells and abnormal restoration after habu-snake venom (HSV)-induced glomerulonephritis. In this study, we examined the relationship of TNC and platelet-derived growth factor receptor (PDGFR) in glomerular mesangial cells. TNC and PDGFR-alpha and -beta transcriptions were up-regulated in wild type (WT) mice after HSV injection, but in TNKO mice PDGFR-alpha transcription was not up-regulated. Immunohistochemistry showed that PDGFR-alpha was found in mesangial areas of colocalized alpha-smooth muscle actin, but in TNKO mice it was not detectable. In vitro studies showed that the expressions of PDGFR-alpha and -beta mRNA and protein in cultured glomerular mesangial cells (GMC) of TNKO mice were lower than those in WT GMC. These results suggest that failures of both TNC and PDGFR-alpha are a candidate for abnormal restoration of TNKO mice.

Elongated dermatan sulphate in post-inflammatory healing skin distributes among collagen fibrils separated by enlarged interfibrillar gaps

It has been reported that the disaccharide composition of dermatan sulphate shows transient changes after epicutaneous application of the hapten 2,4-dinitrofluorobenzene to mouse skin, and that these changes are most conspicuous in healing skin on day 15 after chemical insult [Kuwaba, Nomura, Irie and Koyama (1999) J. Dermatol. Sci. 19, 23-30]. In the present study it was found that the molecular size of dermatan sulphate was increased on day 15 after hapten application. The molecular size of decorin increased in healing skin, whereas the size of dermatan-sulphate-depleted core protein did not increase. The length and localization of decorin dermatan sulphate were investigated by electron microscopy. Dermatan sulphate filaments oriented orthogonally to collagen fibrils were longer in healing skin than in control skin. In control skin, dermatan sulphate filaments were found among tightly packed collagen fibrils. In contrast, the interfibrillar gaps between each collagen fibril were enlarged in healing skin; elongated dermatan sulphate filaments extended from the surface of collagen fibrils across the enlarged gap. These results suggest that the increase in molecular size of decorin dermatan sulphate is important in organizing collagen fibrils separated by enlarged interfibrillar gaps in healing skin.

Elongated dermatan sulphate in post-inflammatory healing skin distributes among collagen fibrils separated by enlarged interfibrillar gaps

It has been reported that the disaccharide composition of dermatan sulphate shows transient changes after epicutaneous application of the hapten 2,4-dinitrofluorobenzene to mouse skin, and that these changes are most conspicuous in healing skin on day 15 after chemical insult [Kuwaba, Nomura, Irie and Koyama (1999) J. Dermatol. Sci. 19, 23-30]. In the present study it was found that the molecular size of dermatan sulphate was increased on day 15 after hapten application. The molecular size of decorin increased in healing skin, whereas the size of dermatan-sulphate-depleted core protein did not increase. The length and localization of decorin dermatan sulphate were investigated by electron microscopy. Dermatan sulphate filaments oriented orthogonally to collagen fibrils were longer in healing skin than in control skin. In control skin, dermatan sulphate filaments were found among tightly packed collagen fibrils. In contrast, the interfibrillar gaps between each collagen fibril were enlarged in healing skin; elongated dermatan sulphate filaments extended from the surface of collagen fibrils across the enlarged gap. These results suggest that the increase in molecular size of decorin dermatan sulphate is important in organizing collagen fibrils separated by enlarged interfibrillar gaps in healing skin.

Type I collagen is a non-adhesive extracellular matrix for macrophages

Macrophages adhere to a variety of substrata including plastic, glass or an extracellular matrix either in a highly specific manner or through less specific mechanisms. We investigated the effect of type I collagen, the most abundant protein in animal tissues, on the adhesion of macrophages derived from a human monoblastic cell line U937. Macrophages were observed to adhere very weakly to type I collagen and aggregate, whereas they adhered firmly and spread on plastic, bovine serum albumin or fibronectin. On the adhesive substratum, the lower surface of the macrophages was flat and closely apposed to the substratum. In contrast, macrophages adhered on type I collagen at the tip of cell processes. The adhesion of macrophages to plastic, bovine serum albumin or fibronectin was associated with the induction of tyrosine phosphorylation of a variety of proteins including a major protein band at 66 kDa. In contrast, the induction of tyrosine phosphorylation was markedly reduced when the macrophages were cultured on type I collagen. Two members of the src family, Lyn and Hck, were tyrosine phosphorylated in firmly adhered macrophages but not in macrophages cultured on type I collagen. These results suggest that the adhesion of macrophages is associated with the tyrosine phosphorylation of a variety of proteins including Lyn and Hck, and that type I collagen serves as a non-adhesive substratum for macrophages, resulting in an altered signal transduction.

Spatiotemporal changes of fibronectin, tenascin-C, fibulin-1, and fibulin-2 in the skin during the development of chronic contact dermatitis

In order to elucidate how chronic inflammation affects the organization of the extracellular matrix in the skin, a prolonged allergic contact dermatitis was induced in a mouse by repeated application to the ear of 2,4-dinitrofluorobenzene every 3 d for 66 d. Subsequently, the spatiotemporal changes of fibronectin, tenascin-C, fibulin-1, and fibulin-2 in the skin were examined. In the acute phase of inflammation (day 3-day 12), the amount of fibronectin and tenascin-C increased markedly and were degraded, whereas the amount of fibulin-2 changed slightly. Abundant deposition of tenascin-C was observed in the connective tissue. Fibulin-1 and fibulin-2 distributed as fine fibrils. In contrast, the amounts of fibronectin and tenascin-C decreased and their degradation was suppressed in the chronic phase (day 15-day 66), but the amount of fibulin-2 increased. Tenascin-C was observed mainly at and underneath the epidermal basement membrane. In the subepidermal region, many fibulin-2-positive microfibrils were distributed. The amount and distribution of fibulin-1 did not change markedly in either phase. MMP-like enzymes of 62 kDa, probably activated MMP-2, were upregulated in the chronic phase, whereas components of 92, 85, or 67 kDa were highly induced in the acute phase. These results suggest that chronic inflammation in allergic contact dermatitis is associated with temporal changes in the expression, deposition, and degradation of inducible extracellular matrix components.

The tenascin-C knockout revisited

In the past seven years, two groups have independently produced tenascin-C-knockout mice. These mice are born alive and, originally, were described as showing no abnormalities. More recent studies, many involving pathological intervention, have shown that tenascin-C-knockout mice have several defects. The mice exhibit abnormal behaviour, as well as abnormalities in brain chemistry. They also show defects in structure and repair of neuromuscular junctions, in the ability to recover from snake-venom-induced glomerulonephritis and in chemically induced dermatitis. Healing of skin wounds is morphologically normal, but the mice exhibit defects in healing after suture injury of corneas. In both skin and corneal wounds, fibronectin expression is abnormally low in tenascin-C-knockout mice. Finally, in vitro studies indicate that haemopoietic activity is defective in bone marrow from these mice. When examined together, these studies provide evidence for precise functions for tenascin-C, as well as an explanation for why the sequence of tenascin-C is so highly phylogenetically conserved.

Spatial and temporal changes in chondroitin sulfate distribution in the sclerotome play an essential role in the formation of migration patterns of mouse neural crest cells

We have examined the roles of pertinent extracellular matrix molecules in the formation of the neural crest cell migration patterns in the sclerotome of the mouse embryo. The present data indicate that permissiveness for migration is inversely correlated with chondroitin sulfate content. Experimental removal of chondroitin sulfate proteoglycans in the embryo causes neural crest cells to migrate even within the posterior half of the somite, which they do not invade ordinarily. Moreover, three different sclerotomal regions defined by the presence or absence of the ventromedial and/or ventrolateral pathways are present along the anteroposterior axis and undergo systematic temporal changes that affect migration patterns. The most anterior portion of the sclerotome is conducive to both ventromedial and ventrolateral migration (Anterior Region). The intermediate portion is conducive to ventromedial migration only (Intermediate Region). No neural crest cells are seen within the posterior portion of the sclerotome (Posterior Region). At this level, they are observed exclusively in the dorsolateral space adjacent to the roof of the neural tube. With advancing embryonic development, the rostrocaudal length of the Anterior Region decreases and is accompanied by a corresponding enlargement of the Intermediate Region. These results suggest that temporal and regional differences in the sclerotome contribute to the neural crest cell migration patterns in the mouse. To refine our understanding of the underlying mechanisms, regional differences and temporal changes in the distribution of extracellular matrix molecules have been examined during migration. In the sclerotome, chondroitin sulfate displays distinct distribution patterns that are closely correlated with the migration patterns of mouse neural crest cells. Furthermore, their migration patterns are altered in embryos treated with the inhibitors of chondroitin sulfate proteoglycan biosynthesis, sodium chlorate, and beta-D-xyloside. In inhibitor-treated embryos, neural crest cell migration occurs even in the posterior portion of the sclerotome. The metameric organization of dorsal root ganglia is disturbed in these embryos. Our observations provide novel evidence for the importance of sclerotomal chondroitin sulfate distribution patterns in mouse crest cell migration patterns. We conclude that systematic spatiotemporal changes in the distribution of chondroitin sulfate proteoglycans are a key requisite for the formation of migration patterns of mouse neural crest cells in the sclerotome.

Temporal changes in disaccharide composition of dermatan sulfate in the skin after epicutaneous application of hapten

Glycosaminoglycans change their amount, structure and distribution with age, differentiation and pathologic conditions. In order to investigate temporal changes in dermatan sulfate in the skin during inflammation and subsequent healing, 2,4-dinitrofluorobenzene (DNFB) was applied once to the dorsal skin of female BALB/cA mice, and the disaccharide composition of dermatan sulfate was examined. Application of DNFB induced a transient increase in the thickness of the dermis, which reached a maximum on day 15 and decreased to the control level on day 35. The total amount of unsaturated disaccharides from dermatan sulfate per cm2 in the DNFB-treated skin showed a temporal pattern similar to that of the thickness of the dermis. Mol% of 4,5-unsaturated 2-sulfo-hexuronic acid-4-sulfated N-acetylgalactosamine (deltaDi-diSB), the second most abundant unsaturated disaccharide from dermatan sulfate, decreased rapidly on day 3 in the DNFB-treated skin, remained less than the control on days 7 and 15, and returned to the control level on day 35. These results suggest that a single application of DNFB induces temporal changes not only in the amount but also in the structure of dermatan sulfate.

Effect of tenascin-C deficiency on chemically induced dermatitis in the mouse

Tenascin-C is a large extracellular matrix glycoprotein characterized by its spatiotemporal expression during embryogenesis, carcinogenesis, and wound healing. Many in vitro studies on tenascin-C have revealed its multifunctional properties; however, disruption of the tenascin-C gene did not reveal any obvious abnormalities during development, and its function in vivo remains unclear. Here, we investigated whether tenascin-C is involved in inflammatory dermatitis in adults by studying chemically induced dermatitis in tenascin-C knockout mice. An epicutaneous application of a hapten, 2,4-dinitrofluorobenzene, to the ear skin of BALB/CA mice resulted in inflammation and induced the expression of tenascin-C. In congenic tenascin-C knockout mice, the dermatitis occurred more severely than in wild-type mice; infiltration of polymorphonuclear cells in knockout mice persisted longer than in wild-type mice, and the elastosis-like disorganized extracellular matrix was also seen in the ear. These results suggest that tenascin-C plays a role in vivo in inflammatory responses in the skin, and that the genetic background has profound effects on the function of tenascin-C in mouse dermatitis.