Aarne Oikarinen

The Short and Long Forms of Type XVIII Collagen Show Clear Tissue Specificities in Their Expression and Location in Basement Membrane Zones in Humans

Two N-terminal ends of human type XVIII collagen chains have recently been identified. The two chains have different signal peptides and variant N-terminal noncollagenous NC1 domains of 493 (NC1-493) and 303 (NC1-303) amino acid residues, respectively, but share 301 residues of their NC1 domains as well as the collagenous and C-terminal noncollagenous portions of the molecule. Antibodies were produced against the NC1 region common to both human alpha1(XVIII) chain variants and against NC1 sequences specific to the long variant and were used in combination with in situ hybridization to localize this collagen in a number of human tissues. They were also used for Western blotting, which resulted in detection of overlapping high-molecular weight bands above the 200-kd standard in a kidney extract. Heparin lyase II and heparin lyase III digestions of kidney and placenta extracts indicated that at least in these tissues, type XVIII collagen contains heparin sulfate glycosaminoglycan side chains. Type XVIII collagen was found to be a ubiquitous basement membrane component, occurring prominently at vascular and epithelial basement membranes throughout the body. Comparison of the expression of the NC1-493 and NC1-303 variants revealed marked differences. The short variant was found in most conventional basement membranes, including blood vessels and the various epithelial structures, and around muscular structures. The long variant was expressed very strongly in liver, where it was virtually the only variant in the liver sinusoids, and it occurred only in minor amounts elsewhere. Thus, the 192 N-terminal residues specific to the long variant apparently confer some functional property needed above all in the liver sinusoids, but also at certain other locations.

Smoking affects collagen synthesis and extracellular matrix turnover in human skin

Summary Background Smoking is associated with premature facial wrinkling and aberrant wound healing, but the underlying mechanisms of skin injury are poorly understood.

Laminin-5 Expression Is Independent of the Injury and the Microenvironment During Reepithelialization of Wounds

We examined the expression of laminin-5 and its integrin receptors during reepithelialization of human wounds. We used suction blisters of skin as a model of keratinocyte migration on a basement membrane matrix and mucosal full-thickness wounds as a model in which keratinocytes migrate in a provisional matrix. An animal model, in which human epidermal keratinocytes were injected into the back of athymic mice, was used to follow the deposition of the basement membrane components. In 4-day-old blisters, about 20–50 cells at the leading edge of the migrating tongue showed cytoplasmic laminin-5 immunostaining. Laminin-5 mRNA was detected in 15–30 cells at the leading edge of the migrating epidermis. α3β1 and α6β4 integrins were found in membrane projections of the migrating basal cells and also in suprabasal cell layers, suggesting their combined role in binding laminin-5. In mucosal wounds, laminin-5 was the only basement membrane zone component that was deposited between the clot and the migrating keratinocytes. In the animal model, linear deposition of laminin-5 and α6β4 integrin was already seen on Day 2, whereas the other basement membrane zone components were not yet organized. The results suggest that, regardless of the injury and the microenvironment, laminin-5 plays an essential role in the interaction between wound keratinocytes and the surrounding matrix.

The effect of topical oestradiol on skin collagen of postmenopausal women

Objective To examine the effect of topical oestradiol on skin collagen and elastin.

72 KD and 92 KD type IV collagenase, type IV collagen, and laminin mRNAs in breast cancer: a study by in situ hybridization.

It is widely accepted that basement membrane (BM) components are synthesized by epithelial cells and that production of BM-degrading proteases by cancer cells is necessary for invasive growth. In this study we used nucleic acid in situ hybridization (ISH) to investigate the presence of mRNAs for 72 KD and 92 KD Type IV collagenase, alpha 1 (IV) chain of Type IV collagen, and laminin B1 chain in 20 breast carcinomas of various histological types. The mRNA signals for 72 KD Type IV collagenase, Type IV collagen, and laminin were much more abundant in stromal fibroblasts and endothelial cells than in carcinoma cells. The signal for 92 KD Type IV collagenase mRNA was strong in carcinoma cells and considerably weaker in stromal fibroblasts and endothelial cells. Labeling for 72 KD and 92 KD Type IV collagenase mRNA was also found in benign fibroadenomas and for 92 KD Type IV collagenase in non-neoplastic ducts and acini. The results indicate that stromal cells have a more important role in the synthesis and degradation of BMs in breast carcinomas than previously thought and that production of these enzymes is not restricted to malignancy.

Altered distribution and synthesis of laminin‐5 (kalinin) in oral lichen planus, epithelial dysplasias and squamous cell carcinomas

Laminin‐5 is a glycoprotein which mediates epithelial cell adhesion to the basement membrane. This study describes the distribution and synthesis of laminin‐5 in oral lichen planus, epithelial dysplasias, squamous cell carcinomas and a lymph node metastasis using immunohistochemistry and in situ hybridization. In normal oral mucosa and lichen planus, immunoreaction to the laminin‐5 was seen as a thin continuous, delicate line in the basement membrane region, although slight irregularities in the thickness and intensity of the immunoreaction could be detected in some cases with lichen planus. In epithelial dysplasias, the laminin‐5 staining was discontinuous and more diffuse compared to lichen planus and normal mucosa. The immunoreaction was generally extracellular, although in some cases with lichen planus and epithelial dysplasia there were a few basal epithelial cells showing cytoplasmic staining. The invasive carcinomas and the lymph node metastasis showed a striking, intense cytoplasmic, staining of the carcinoma cells along the invasive border of the neoplastic islands and in individual infiltrating carcinoma cells. Using in situ hybridization, the laminin‐5 γ2 chain mRNA expression could not be detected in normal oral mucosa whereas, in non‐dysplastic lichen planus and, more strongly, in dysplasias, there was a clear increase in the expression of laminin‐5 mRNA in the basal epithelial cells. The most intensive signal was detected in the invasive front of the oral squamous cell carcinomas and the lymph node metastasis. We conclude that, in oral squamous cell carcinoma, there is altered synthesis and secretion of laminin‐5 mRNA and protein. It is also evident that in dysplastic lesions of oral epithelium the synthesis and distribution of laminin‐5 is abnormal.

mRNA expressions of TIMP-1, -2, and -3 and 92-KD type IV collagenase in early human placenta and decidual membrane as studied by in situ hybridization.

Cytotrophoblasts of early placenta invade the decidual membrane, gestational endometrium, and spiral arteries during early pregnancy. Unlike tumor invasion, this physiological invasion is well controlled, although its molecular mechanisms are largely unknown. We have previously shown that cytotrophoblasts synthesize significant mRNAs for 72-KD Type IV collagenase, laminin, and Type IV collagen, proteins implicated in extracellular matrix turnover and migration. In this study we used in situ hybridization and immunohistochemistry to investigate the mRNA expression pattern of 92-KD Type IV collagenase and the matix metalloproteinase inhibitors TIMP-1, TIMP-2, and TIMP-3 in early human placenta and decidual membrane. mRNAs for 92-KD Type IV collagenase, TIMP-1, TIMP-2, and TIMP-3 were found in the cells of cytotrophoblastic columns, the endothelial and fibroblastic stromal cells of villi, and the large decidualized cells of decidual membrane. TIMP-1 expression was notably accentuated in the fibroblasts of fibrotic villi. In the decidual membrane, the signals for 92-KD Type IV collagenase and TIMP-1 mRNA were particularly strong around the glandular structures. The trophoblastic epithelium of villi and the epithelial cells of decidual glands showed a signal for 92-KD Type IV collagenase and TIMP-2, but not for TIMP-1 or TIMP-3. The coincidental expression of the proteolytic 92-KD Type IV collagenase and inhibitors TIMP-1, TIMP-2, and TIMP-3 generally in the same cells suggests that the activity of 92-KD Type IV collagenase, which is regulated by TIMPs, plays an important role in placental tissue organization and in the invasion of trophoblastic cells into the uterine wall.

Systemic therapy with estrogen or estrogen with progestin has no effect on skin collagen in postmenopausal women

OBJECTIVES To investigate the effect of estrogen alone or combined with progestin on the amount and synthesis of skin collagen in postmenopausal women. METHODS Forty-three early postmenopausal women were enrolled into this open, non-randomized parallel-groups study. Fifteen women received a continuous oral dose of 2 mg of 17 beta-estradiol and 1 mg of norethisterone acetate daily and 14 women an oral dose of 2 mg estradiol valerate daily. Fourteen subjects served as controls. The histology and type I and III procollagen immunohistochemistry of the skin, skin thickness, the amount of total collagen determined by a colorimetric method and the synthesis of type I and III collagens determined by analysing procollagen propeptides in the suction blister fluid were studied before the treatment and at 6 and 12 months. The proportional area of elastic fibers and the thickness of the epidermis were assessed from the sections obtained before the treatment and at 12 months, with computerized image analysis. RESULTS Skin thickness, the amount and rate of collagen synthesis, the proportional area of elastic fibers and the thickness of the epidermis were not affected by either 17 beta-estradiol and 1 mg of norethisterone acetate or 2 mg of estradiol valerate. No histological or immunohistological changes were detected in the skin specimens during the 12-month treatment period compared to the baseline or to the skin specimens of the control group. CONCLUSIONS A 1-year treatment with systemic estrogen alone or combined with progestin does not change the amount of collagen or the rate of collagen synthesis in postmenopausal women.

Systemic glucocorticoid treatment decreases serum concentrations of carboxyterminal propeptide of type I procollagen and aminoterminal propeptide of type III procollagen

The effect of systemic glucocorticoid treatment on collagen synthesis in patients with various dermatoses was studied by measuring the carboxyterminal propeptide of type I procollagen (PICP) and the aminoterminal propeptide of type III procollagen (PIIINP) in serum. Changes in the propeptide concentrations were compared with those of osteocalcin, which reflects osteoblastic activity, and tartrate resistant acid phosphatase (TRAP), which reflects osteoclastic activity. The treatment caused significant decreases in levels of PICP, PIIINP and osteocalcin of 38, 34 and 49%, respectively (P<0.001). For TRAP, both increases and decreases were seen. The effects on PICP and PIIINP were evident 2–4 days after the onset of steroid therapy. The decreases in PICP was dose‐related (r=0.470, P<0.005) but even relatively small doses (0.1 mg of prednisone/kg/1 day) caused a significant reduction in PICP. After cessation of treatment, the levels of PICP returned to the pretreatment level in 1 week. The present study demonstrates that systemic glucocorticoid therapy in humans suppresses the synthesis of type I and III collagens and also non‐collagenous bone matrix proteins.

ABERRANT ACCUMULATION OF P53 ASSOCIATES WITH KI67 AND MITOTIC COUNT IN BENIGN SKIN LESIONS

Sixty‐two skin samples from patients with a variety of benign disorders (20 cases of psoriasis, 14 cases of chronic dermatitis, 11 seborrhoeic keratoses, 11 cases of lichen planus), and seven normal skin samples, were stained immunohistochemically with a polyclonal antibody (CM‐1) to p53, and a monoclonal antibody to Ki67, using the avidin‐biotin complex method, p53‐positive keratinocytes could be found in most of these lesions. The percentage of p53‐positive cells was, however, far lower than usually seen in p53‐positive malignant tumours. No p53 reactivity was observed in the normal skin samples. Variable Ki67 reactivity was observed in all skin samples. Overall, the number of Ki67‐positive cells was higher in skin samples in which the proportion of p53‐positive cells was high (>0.5% of total epidermal cell population) (P=0.004). This also applied separately to psoriatic and non‐psoriatic lesions (P=0.028 and P=0.033, respectively). In cases with >10% of Ki67‐positive cells, there were significantly more mitoses (P<0.001). This association applied to both psoriasis and the other lesions studied (P=0.024 and P <0.001, respectively). The results show that immunohistochemically detectable accumulation of p53 is a frequent finding in non‐neoplastic skin lesions. As p53 positivity was associated with the proliferation marker Ki67, the accumulation of p53 is possibly a response to an increased proliferation rate of the keratinocytes in these skin diseases, or alternatively it may be associated with apoptosis.