Immunohistochemical evaluation of cartilage-derived morphogenic protein-1 and -2 in normal human salivary glands and pleomorphic adenomas

Cartilage-derived morphogenic protein (CDMP)-1 and -2 belong to the bone morphogenetic protein (BMP) family in the transforming growth factor (TGF)-beta superfamily. CDMP-1 and CDMP-2 were reported to play essential roles in limb cartilage and limb-joint formation in developing mice. Although pleomorphic adenoma of the salivary glands is an epithelial tumor, it frequently shows ectopic cartilaginous formation. These findings suggested that CDMP-1 and -2 may play essential roles in chondroid formation in salivary pleomorphic adenoma. To evaluate this hypothesis, we examined the expression and localization of CDMP-1 and -2 immunohistochemically in 20 normal human salivary glands and 35 pleomorphic adenomas. CDMP-1 was immunolocalized in the striated ducts and the intercalated ducts in the normal salivary glands. CDMP-1 was immunolocalized in the cuboidal neoplastic myoepithelial cells around the chondroid areas of the pleomorphic adenomas, whereas these molecules were not localized in the spindle-shaped neoplastic myoepithelial cells of the myxoid element or the lacuna cells of the chondroid element in these tumors. CDMP-2 was expressed neither in normal salivary glands nor any of the elements of the pleomorphic adenomas. Type-II collagen and aggrecan were immunolocalized throughout the matrix around the lacuna cells of the chondroid element, whereas type-X collagen was not immunolocalized in any epithelial or stromal elements, including the chondroid elements. Aggrecan was deposited not only on the chondroid matrix, but also on the myxoid stroma and intercellular spaces of the tubulo-glandular structures, whereas chondromodulin-I was deposited on the chondroid matrix. These results indicated that the cuboidal neoplastic myoepithelial cells around the chondroid areas expressed CDMP-1 and suggested that this molecule may play a role in the differentiation of neoplastic myoepithelial cells in pleomorphic adenoma. The phenotype of the lacuna cells was similar to that of mature to upper hypertrophic chondrocytes of the authentic cartilage. In conclusion, pleomorphic adenoma expressed CDMP-1 but not CDMP-2.     

Niemann‐Pick disease type B: An unusual clinical presentation with multiple vertebral fractures*

We report here a unique case of a 55‐year‐old woman presenting with a clinical picture of Parkinson disease, severe back pain, splenomegaly, and pronounced dyspnea. Radiographic examination of the spine showed multiple vertebral fractures. Niemann‐Pick disease type B was diagnosed by findings of lipid‐loaded histiocytes and a strongly reduced sphingomyelinase enzyme activity. She was homozygous for the deletion of codon 608 (delR608), which encodes an arginine residue in the Acid Sphingomyelinase gene. To investigate the cause of the unusual vertebral fractures, we screened for polymorphisms previously described as possibly associated with increased risk for osteoporosis and fractures. Our patient was heterozygous for the polymorphisms of the vitamin D receptor gene, the estrogen receptor gene, and the collagen 1A1gene. Increased physical activity after Parkinson treatment, a genetic predisposition, together with worsening disease due to interfering medications could explain the dramatic presentation of this patient. She was treated with cholesterol lowering drugs such as statins to decrease sphingomyelin synthesis, avoidance of drugs that inhibit sphingomyelinase, and bisphosphonates. No new fractures have occurred, but the interstitial lung disease has progressed. © 2002 Wiley‐Liss, Inc.     

Integrin‐Linked Kinase Regulates Bone Formation by Controlling Cytoskeletal Organization and Modulating BMP and Wnt Signaling in Osteoprogenitors

Cell‐matrix interactions constitute a fundamental aspect of skeletal cell biology and play essential roles in bone homeostasis. These interactions are primarily mediated by transmembrane integrin receptors, which mediate cell adhesion and transduce signals from the extracellular matrix to intracellular responses via various downstream effectors, including integrin‐linked kinase (ILK). ILK functions as adaptor protein at focal adhesion sites, linking integrins to the actin cytoskeleton, and has been reported to act as a kinase phosphorylating signaling molecules such as GSK‐3β and Akt. Thereby, ILK plays important roles in cellular attachment, motility, proliferation and survival. To assess the in vivo role of ILK signaling in osteoprogenitors and the osteoblast lineage cells descending thereof, we generated conditional knockout mice using the Osx‐Cre:GFP driver strain. Mice lacking functional ILK in osterix‐expressing cells and their derivatives showed no apparent developmental or growth phenotype, but by 5 weeks of age they displayed a significantly reduced trabecular bone mass, which persisted into adulthood in male mice. Histomorphometry and serum analysis indicated no alterations in osteoclast formation and activity, but provided evidence that osteoblast function was impaired, resulting in reduced bone mineralization and increased accumulation of unmineralized osteoid. In vitro analyses further substantiated that absence of ILK in osteogenic cells was associated with compromised collagen matrix production and mineralization. Mechanistically, we found evidence for both impaired cytoskeletal functioning and reduced signal transduction in osteoblasts lacking ILK. Indeed, loss of ILK in primary osteogenic cells impaired F‐actin organization, cellular adhesion, spreading, and migration, indicative of defective coupling of cell‐matrix interactions to the cytoskeleton. In addition, BMP/Smad and Wnt/β‐catenin signaling was reduced in the absence of ILK. Taken together, these data demonstrate the importance of integrin‐mediated cell‐matrix interactions and ILK signaling in osteoprogenitors in the control of osteoblast functioning during juvenile bone mass acquisition and adult bone remodeling and homeostasis. © 2017 American Society for Bone and Mineral Research.     

Inhibition of osteoclasts does not prevent joint ankylosis in a mouse model of spondyloarthritis

Objectives. The relationship between inflammation, destructionand new tissue formation leading to ankylosis, determines theseverity and prognosis of patients with SpA. Recent data inmice and men suggest that new cartilage and bone formation andsubsequent ankylosis are uncoupled from chronic inflammation.These data challenge the hypothesis that inflammation and tissuedamage trigger an excessive repair response in SpA. We testedwhether inhibition of bone erosion by targeting osteoclasts,would prevent or influence joint ankylosis in a mouse model. Methods. Male DBA/1 mice from different litters were caged togetherat the age of 8 weeks. Treatment with zoledronic acid (ZA) (100ng/g) or placebo was started at the age of 10 weeks and administeredevery 2 weeks. Clinical incidence and severity of arthritiswere evaluated twice a week until the age of 26 weeks. At thispoint, bone density measurements were performed, mice were sacrificedand severity of arthritis was evaluated by histology. Results. Treatment with ZA did not affect incidence or clinicalseverity of arthritis in male DBA/1 mice. ZA treatment significantlyincreased bone mineral density and content as demonstrated bydual X-ray densitometry and peripheral quantitative CT. However,the treatment did not affect histomorphological appearance ofarthritis or ankylosis. Conclusions. These data suggest that bone erosion at the enthesisdoes not necessarily precede entheseal ankylosis. Therefore,these observations further support the concept that inflammationand new tissue formation in SpA are at least partially uncoupledevents and may be different therapeutic targets. KEY WORDS: Spondyloarthritis, AS, PsA, Ankylosis, Enthesis, Osteoclasts, Bisphosphonates Submitted 14 December 2007; revised version accepted 1 February 2008.     

Comparison of the ligand binding and signaling properties of human dopamine D(2) and D(3) receptors in Chinese hamster ovary cells.

Human dopamine D(2) (hD(2)) and D(3) (hD(3)) receptors were expressed at similar, high expression levels in Chinese hamster ovary (CHO) cells, and their coupling to G proteins and further signal transduction pathways were compared. In competition radioligand-binding experiments, guanosine-5'-O-(3-thio)triphosphate (GTPgammaS) treatment of hD(2S)- or hD(3)-CHO cell membranes induced a rightward shift and steeping of the dopamine inhibition curve. This effect was pronounced for hD(2) receptors and small for hD(3) receptors. Activation of G proteins was investigated in [(35)S]GTPgammaS-binding assays. Dopamine stimulated [(35)S]GTPgammaS binding 330 and 70% over basal levels on hD(2)-CHO and hD(3)-CHO cell membranes, respectively. (+)-7-(Dipropylamino)-5, 6,7,8-tetrahydro-2-naphthalenol and PD128907 were partial agonists for both receptors. Haloperidol, risperidone, raclopride, and nemonapride inhibited dopamine-stimulated [(35)S]GTPgammaS binding with potencies comparable to their binding affinities for hD(2) and hD(3) receptors in CHO cell membranes; inverse agonism could not be detected with this assay. Receptor stimulation by dopamine inhibited forskolin-induced cyclic AMP formation in hD(2)-CHO and hD(3)-CHO cells by 70%. Furthermore, the extracellular acidification rate increased when hD(2)-CHO and hD(3)-CHO cells were stimulated by dopamine; this effect was abolished by pertussis toxin pretreatment. In this study, we could demonstrate clear functional effects at different levels of the signaling cascade of hD(2) and hD(3) receptors in CHO cells when expressed at high levels. High-affinity agonist binding to hD(2) and hD(3) receptors was still present, but effects of receptor-G protein uncoupling at hD(3) receptors were small, indicating that hD(3) receptors maintain relatively high-affinity agonist binding in the absence of G proteins.     

Dependence on interferon‐γ for the spontaneous occurrence of arthritis in DBA/1 mice

Objective

Male DBA/1 mice are known to spontaneously develop arthritis in the hind legs. The present study was undertaken to investigate the role of endogenous interferon‐γ (IFNγ) in the pathogenesis of this ankylosing enthesopathy.

Methods

The role of IFNγ was studied by examining the development of arthritis in IFNγ receptor–knockout (IFNγR‐KO) DBA/1 mice as compared with wild‐type mice, and by treatment of wild‐type mice with monoclonal anti‐IFNγ antibody. IFNγ‐disrupted and wild‐type mice were mixed and housed in the same cage, and clinical symptoms of arthritis were assessed weekly for at least 9 weeks. Histologic examination was performed at the end of the experiment.

Results

In DBA/1 wild‐type mice, 70% of the animals developed clinical symptoms of spontaneous arthritis, such as redness and swelling of the proximal interphalangeal joints, toe stiffness, and ankylosis. As evident from microscopic evaluation, the arthritis was mainly characterized by formation of new cartilage and bone, originating at the entheses and leading to ankylosis. The incidence and severity of arthritis, both clinically and histologically, were significantly reduced in IFNγR‐KO mice. In wild‐type mice, neutralizing anti‐IFNγ antibody inhibited the occurrence of the disease for the duration of treatment.

Conclusion

The results suggest that endogenous IFNγ plays an important role in the initial stages of spontaneous arthritis, and that the inflammatory components in its pathogenesis are more prominent than has been believed. In view of the similarity between this disease and spondylarthropathies in humans, the data suggest that endogenous IFNγ may also play a disease‐promoting role in the human condition and thus may serve as a target for therapy.

     

Galantamine is an allosterically potentiating ligand of the human α4/β2 nAChR

Galantamine (Reminyl^TM) is a novel drug treatment for mild to moderate Alzheimer's disease (AD). Originally established as a reversible inhibitor of the acetylcholine-degrading enzyme acetylcholinesterase (AChE), galantamine also acts as an allosterically potentiating ligand (APL) on nicotinic acetylcholine receptors (nAChR). Having previously established this second mode of action on nAChRs from murine brain, we demonstrate here the same action of galantamine on the most abundant nAChR in the human brain, the α4/β2 subtype. This nAChR-sensitizing action is not a common property of all, or most, AChE inhibitors, as is shown by the absence of this effect for other therapeutically applied AChE inhibitors including tacrine, metrifonate, rivastigmine and donepezil. The possible benefits for therapy of AD of an APL action on nicotinic receptors is discussed.     

Two-year results after combined phacoemulsification and iris-fixated phakic intraocular lens removal

Graefe's Archive for Clinical and Experimental Ophthalmology - To describe and present results after a technique for cataract surgery combined with explantation of an iris-fixated phakic...