Osteopontin: a new emerging role in psoriasis

The Role of Osteopontin in Psoriasis-A Scoping Review

Psoriasis is a chronic systemic disease with an immunological basis and a complex pathophysiology. The chronic inflammatory status of psoriasis is associated with several comorbidities, such as metabolic syndrome, obesity, and cardiovascular disease. The development of psoriasis is influenced by osteopontin, a glycoprotein that influences physiological and pathological reactions by modulating Th1 and Th17 cellular responses, stimulating keratinocyte proliferation, regulating cellular apoptosis, and promoting angiogenesis. The recent identification of immune pathways involved in psoriasis development has facilitated the development of biological treatments; however, a better understanding of the intricate relationship between underlying inflammatory processes, psoriasis development, and accompanying comorbidities is needed for improved disease management.

Loricrin and Cytokeratin Disorganisation in Severe Forms of Periodontitis

OBJECTIVE

The aim of this research was to investigate the role of the cornified epithelium, the outermost layer of the oral mucosa, engineered to prevent water loss and microorganism invasion, in severe forms of periodontitis (stage III or IV, grade C).

METHODS

Porphyromonas gingivalis, a major periodontal disease pathogen, can affect cornified epithelial protein expression through chronic activation of signal transducer and activator of transcription 6 (Stat6). We used a mouse model, Stat6VT, that mimics this to determine the effects of barrier defect on P gingivalis-induced inflammation, bone loss, and cornified epithelial protein expression, and compared histologic and immunohistologic findings with tissues obtained from human controls and patients with stage III and IV, grade C disease. Alveolar bone loss in mice was assessed using micro-computerised tomography, and soft tissue morphology was qualitatively and semi-quantitatively assessed by histologic examination for several proteins, including loricrin, filaggrin, cytokeratin 1, cytokeratin 14, a proliferation marker, a pan-leukocyte marker, as well as morphologic signs of inflammation. Relative cytokine levels were measured in mouse plasma by cytokine array.

RESULTS

In the tissues from patients with periodontal disease, there were greater signs of inflammation (rete pegs, clear cells, inflammatory infiltrates) and a decrease and broadening of expression of loricrin and cytokeratin 1. Cytokeratin 14 expression was also broader and decreased in stage IV. P gingivalis-infected Stat6VT mice showed greater alveolar bone loss in 9 out of 16 examined sites, and similar patterns of disruption to human patients in expression of loricrin and cytokeratins 1 and 14. There were also increased numbers of leukocytes, decreased proliferation, and greater signs of inflammation compared with P gingivalis-infected control mice.

CONCLUSIONS

Our study provides evidence that changes in epithelial organisation can exacerbate the effects of P gingivalis infection, with similarities to the most severe forms of human periodontitis.

Osteopontin and Regulatory T Cells in Effector Phase of Allergic Contact Dermatitis

Studies have shown that osteopontin (OPN) and regulatory T cells play a role in allergic contact dermatitis (ACD), but the mechanisms responsible for their function are poorly understood. The study aimed to determine CD4 T lymphocytes producing intracellular osteopontin (iOPN T cells) and assess the selected T lymphocyte subsets including regulatory T cells in the blood of patients with ACD. Twenty-six patients with a disseminated form of allergic contact dermatitis and 21 healthy controls were enrolled in the study. Blood samples were taken twice: in the acute phase of the disease and during remission. The samples were analyzed by the flow cytometry method. Patients with acute ACD showed significantly higher percentage of iOPN T cells compared with healthy controls which persisted during remission. An increase in the percentage of CD4CD25 and a reduced percentage of regulatory T lymphocytes (CD4CD25highCD127low) were also found in the patients with acute stage of ACD. The percentage of CD4CD25 T lymphocytes showed a positive correlation with the EASI index. The increase in the iOPN T cells can indicate their participation in acute ACD. The decreased percentage of regulatory T lymphocytes in the acute stage of ACD may be related to the transformation of Tregs into CD4CD25 T cells. It may also indicate their increased recruitment to the skin. The positive correlation between the percentage of CD4CD25 lymphocytes and the EASI index may be indirect evidence for the importance of activated lymphocytes-CD4CD25 in addition to CD8 lymphocytes as effector cells in ACD.

The Effect of Atopic Dermatitis and Diet on the Skin Transcriptome in Staffordshire Bull Terriers

Canine atopic dermatitis (CAD) has a hereditary basis that is modified by interactions with the environment, including diet. Differentially expressed genes in non-lesional skin, determined by RNA sequencing before and after a dietary intervention, were compared between dogs with naturally occurring CAD (n = 4) and healthy dogs (n = 4). The dogs were fed either a common commercial heat-processed high carbohydrate food (kibble diet) (n = 4), or a non-processed high fat food (raw meat-based diet) (n = 4). At the end of the diet intervention, 149 differentially expressed transcripts were found between the atopic and healthy dogs. The main canonical pathways altered by the dysregulation of these genes were angiopoietin signaling, epidermal growth factor signaling, activation of angiogenesis, and alterations in keratinocyte proliferation and lipid metabolism. On the other hand, 33 differently expressed transcripts were found between the two diet groups, of which 8 encode genes that are annotated in the current version of the dog genome: immunoglobulin heavy constant mu (IGHM), immunoglobulin lambda-like polypeptide 5 (IGLL5), B-cell antigen receptor complex-associated protein beta chain (CD79B), polymeric immunoglobulin receptor (PIGR), cystathionine β-synthase (CBS), argininosuccinate synthase 1 (ASS1), secretory leukocyte peptidase inhibitor (SLPI), and mitochondrial ribosome recycling factor (MRRF). All genes were upregulated in the raw diet group. In conclusion the findings of this study suggest alterations in lipid and keratinocyte metabolism as well as angiogenesis in the skin of atopic dogs. Additionally, a possible enhancement of innate immunity and decrease in oxidative stress was seen in raw food fed dogs, which could have an important role in preventing hypersensitivities and disturbed immunity at young age.

Biomechanical Factors in Psoriatic Disease: Defective Repair Exertion as a Potential Cause. Hypothesis Presentation and Literature Review

Joining main clinical manifestations of psoriatic skin disorder are inflammatory arthritis and nail lesions. Repetitive microdamage has been postulated as a main triggering factor in lesions of psoriatic arthritis. This concept of psoriatic disease might also be admissible for triggering nail lesions because the nail is a frequently traumatized structure. Here, we aimed to describe the conjectural injury mechanisms of nail complex with regard to acting biomechanical factors. Tissue repair response to physical microdamage may be altered in psoriatic disease. It is plausible to consider that a defective repair process in the dysregulated prepsoriatic tissue may lead to innate immune activation and further development of autoinflammatory lesions, although excessive inflammation is known to impair wound healing. Recently published data have revealed the importance of mechanosensitive Wingless-type (Wnt) signaling in the pathophysiology of psoriasis and ankylosing spondylitis. The Wnt signaling system is involved in morphogenesis, repair, and regeneration as a biologic process main regulator. Wnt5a seems to be a dominating mediator in both psoriatic plaques and during the spondylitis process that might also be a linking molecule of psoriatic response to mechanical stress. Future studies should focus on complex responsive interactions of tissue repair regulators regarded in psoriatic disease.

Effects of l-carnitine supplementation on cardiovascular and bone turnover markers in patients with pemphigus vulgaris under corticosteroids treatment: A randomized, double-blind, controlled trial

Pemphigus vulgaris (PV) is a severe, bullous, autoimmune disease of the skin and mucous membranes. Corticosteroids are usually the main core treatment for controlling PV, which could lead to several side effects such as insulin resistance, osteoporosis, and cardiovascular disorders. The aim of this study is to evaluate the protective effects of l-carnitine (LC) supplementation in PV patients under corticosteroid treatment. In this randomized, double-blind, placebo-controlled clinical trial, 48 patients with PV were divided randomly into two groups to receive 2 g LC (n = 24) or a placebo (n = 24) for 8 weeks, respectively. Serum levels of osteopontin (OPN), bone morphogenic protein 4 (BMP4), cystatin C, systolic and diastolic blood pressure, 25 hydroxyvitamin D3, and LC were evaluated at the beginning and at the end of the study. LC supplementation demonstrated a significant increase in serum carnitine (p < .001). In addition, at the end of the trial, LC supplementation significantly decreased serum BMP4 (p = .003), OPN (p = .03), and cystatin C (p = .001) levels. There was no significant effect on blood pressure in comparison with the placebo. During study, no harmful side effects were reported by patients. These findings indicate that LC supplementation significantly leads to favorable changes in OPN, BMP4, and cystatin C in PV patients under corticosteroid therapy. However, further investigations are required to confirm these results.

Emerging role of immune cell network in autoimmune skin disorders: An update on pemphigus, vitiligo and psoriasis

Autoimmune skin diseases are a group of disorders that arise due to a deregulated immune system resulting in skin tissue destruction. In the majority of these conditions, either autoreactive immune cells or the autoantibodies are generated against self-antigens of the skin. Although the etiology of these diseases remains elusive, biochemical, genetic, and environmental factors such as infectious agents, toxins damage the skin tissue leading to self-antigen generation, autoantibody attack and finally results in autoimmunity of skin. Immune dysregulation, which involves predominantly T helper 1/17 (Th1/Th17) polarization and the inability of regulatory T cells to regress immune response, is implicated in autoimmune skin diseases. The emerging roles of immune cells, cytokines, and chemokines in the pathogenesis of common autoimmune skin diseases like pemphigus, vitiligo, and psoriasis are discussed in this review. The main focus is on the interplay between immune cell network including the innate and adaptive immune system, regulatory cells, immune checkpoints and recently identified tissue-resident memory cells (TRMs) in disease pathogenesis and relapse. We also attempt to highlight on the immune mechanisms common to these diseases which can be targeted for designing novel therapeutics.

Role of Osteopontin in Psoriasis: An Immunohistochemical Study

Background:

Osteopontin (OPN) has been postulated to have a role in several T-helper (Th) 1 and Th 17-mediated diseases including psoriasis (PS), through multiple mechanisms sharing in the onset and worsening of PS, OPN shares in induction of keratinocyte proliferation through inhibiting keratinocyte apoptosis, OPN acts as a proinflammatory agent that participates in the upregulation of Th cell lineages, among which are the Th 1 and Th 17 cells.

Aims and Objectives:

The aim of this study was to explore the possible role of OPN in the pathogenesis of PS.

Materials and Methods:

This case–control study was carried out on 18 patients of chronic plaque PS (mean age 37.61 ± 14.48) and a control group of 18 apparently healthy volunteers (mean age 41.11 ± 11.02 years). Severity of PS was assessed using the PS area and severity index score. Two skin biopsies were taken from psoriatic patients. The first was taken from the lesional skin and the other from a counter apparently healthy site.

Results:

Our results showed statistically significant differences in the expression of OPN, between lesional and nonlesional skin as well as between nonlesional skin and control group (P ≤ 0.001). In addition, there was a significant difference in the expression of OPN, between control and lesional group.

Conclusions:

OPN involvement in PS enlarges the list of cytokines able to stimulate the inflammatory response in this disease, anti-OPN antibodies, may eventually become a useful therapeutic approach in PS.

Assessment of serum levels of osteopontin, selenium and prolactin in patients with psoriasis compared with healthy controls, and their association with psoriasis severity

BACKGROUND

The association between psoriasis and cardiovascular diseases is well documented, but the underlying mechanisms remain unknown. Overexpression of osteopontin (OPN) has been reported in the plasma of patients with psoriasis, with increased cardiovascular risk factors in these patients. Selenium compounds are effective in downregulating OPN expression.

OBJECTIVE

We investigated the levels of OPN, selenium and prolactin (PRL) in psoriasis, and their association with metabolic status in patients to identify a possible link between these markers and observed comorbidities.

METHODS

Plasma samples from 40 patients with psoriasis and 40 age- and sex-matched healthy controls (HCs) were collected for ELISA. The clinical significance of plasma OPN, selenium and PRL levels in patients compared with controls was analysed in relation to metabolic disorders.

RESULTS

There was no significant difference in median serum selenium levels between the two groups. Serum levels of PRL were not significantly different from those of HCs, but levels of OPN were significantly higher in patients with psoriasis than in HCs.

CONCLUSIONS

High plasma OPN is a predictor for occurrence of psoriasis. Our study showed that serum selenium and PRL were not decreased in patients with psoriasis, but there was a negative statistically significant correlation between OPN and selenium in all participants.

Modification of osteopontin and MMP-9 levels in patients with psoriasis on anti-TNF-α therapy

Psoriasis is a chronic skin inflammatory disease in which a pleiotropic cytokine, tumor necrosis factor alpha (TNF-α), plays a central role, as demonstrated by the clinical success of anti-TNF-α therapy. Among the multiple effects of TNF-α on keratinocytes, the induction of matrix metalloproteinase-9 (MMP-9), a collagenase implicated in joint inflammation, might be one of the key mechanisms in psoriasis pathogenesis. Interestingly, MMP-9 expression can be enhanced also by osteopontin (OPN), a glycosylated protein whose levels are increased in skin and peripheral blood mononuclear cells (PBMC) of psoriasis patients. The aim of the current study is to investigate the relationship between OPN, MMP-9 and TNF-α in psoriasis. Our survey identified high levels of both OPN and MMP-9 in PBMC as well as skin of psoriatic patients with respect to healthy controls. Significant reduction of OPN and MMP-9 levels in PBMC, plasma and lesional skin of psoriasis patients was observed after 24 weeks of anti-TNF-α therapy. Moreover, OPN and MMP-9 were enhanced by TNF-α and down-regulated by anti-TNF-α treatment in healthy PBMC. These findings may suggest that OPN and MMP-9 may be regulated by TNF-α, indicating a possible role in the pathogenesis of psoriasis.

The role of osteopontin (OPN/SPP1) haplotypes in the susceptibility to Crohn's disease

BACKGROUND

Osteopontin represents a multifunctional molecule playing a pivotal role in chronic inflammatory and autoimmune diseases. Its expression is increased in inflammatory bowel disease (IBD). The aim of our study was to analyze the association of osteopontin (OPN/SPP1) gene variants in a large cohort of IBD patients.

METHODOLOGY/PRINCIPAL FINDINGS

Genomic DNA from 2819 Caucasian individuals (n = 841 patients with Crohn's disease (CD), n = 473 patients with ulcerative colitis (UC), and n = 1505 healthy unrelated controls) was analyzed for nine OPN SNPs (rs2728127, rs2853744, rs11730582, rs11739060, rs28357094, rs4754 = p.Asp80Asp, rs1126616 = p.Ala236Ala, rs1126772 and rs9138). Considering the important role of osteopontin in Th17-mediated diseases, we performed analysis for epistasis with IBD-associated IL23R variants and analyzed serum levels of the Th17 cytokine IL-22. For four OPN SNPs (rs4754, rs1126616, rs1126772 and rs9138), we observed significantly different distributions between male and female CD patients. rs4754 was protective in male CD patients (p = 0.0004, OR = 0.69). None of the other investigated OPN SNPs was associated with CD or UC susceptibility. However, several OPN haplotypes showed significant associations with CD susceptibility. The strongest association was found for a haplotype consisting of the 8 OPN SNPs rs2728127-rs2853744-rs11730582-rs11439060-rs28357094-rs112661-rs1126772-rs9138 (omnibus p-value = 2.07×10⁻⁸). Overall, the mean IL-22 secretion in the combined group of OPN minor allele carriers with CD was significantly lower than that of CD patients with OPN wildtype alleles (p = 3.66×10⁻⁵). There was evidence for weak epistasis between the OPN SNP rs28357094 with the IL23R SNP rs10489629 (p = 4.18×10⁻²) and between OPN SNP rs1126616 and IL23R SNP rs2201841 (p = 4.18×10⁻²) but none of these associations remained significant after Bonferroni correction.

CONCLUSIONS/SIGNIFICANCE

Our study identified OPN haplotypes as modifiers of CD susceptibility, while the combined effects of certain OPN variants may modulate IL-22 secretion.

Psoriasis and cardiovascular disease

Current epidemiological data support the association between psoriasis and cardiovascular (CV) risk, in apparent correlation with psoriasis severity. Although less unanimously, evidence of an increased prevalence of CV diseases among psoriasis patients has been reported, including ischemic heart disease, cerebrovascular, peripheral vascular and heart structural disorders. In particular, various studies showed a correlation between psoriasis and major CV events (i.e., myocardial infarction, stroke), while others investigated subclinical changes of blood vessels, such as intima-media thickness increase, arterial stiffness and coronary artery calcification. A series of different mechanisms, like traditional CV risk or iatrogenic risk factors, inflammation, hemostasis dysregulation, hyperhomocysteinemia, and shared genetic susceptibility, are thought to underlie this epidemiological association. Among these elements, inflammation and its related cytokine milieu, including Th1-mediated response and Th17/Treg imbalance, C reactive protein and the newly implicated osteopontin are considered to play a primary role, even if yet to be fully understood.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Osteopontin is associated with increased arterial stiffness in rheumatoid arthritis

Rheumatoid arthritis (RA) patients are characterized by increased arterial stiffness, an independent predictor of cardiovascular risk. It has been suggested that osteopontin (OPN), a cytokine involved in RA pathogenesis, might have vascular effects. To study a possible relationship between OPN and arterial stiffness, aortic pulse wave velocity (PWV) was measured by tonometry in 69 patients (41 with RA, 28 with systemic sclerosis [SSc]) and 18 healthy controls. Plasma OPN levels, oxidative stress markers, and endothelin 1 (ET-1) were assessed. OPN levels were significantly (P < 0.05) higher in RA (median 9.93, range 4.36-47.80 ng/mL) than in SSc (4.3, 2.1-19.7 ng/mL) or controls (5.2, 4.1-9.4 ng/mL). In RA patients, log-OPN was related to log-C-reactive protein (log-CRP) (r = 0.30, P < 0.05), age (r = 0.38, P < 0.01), Health Assessment Questionnaire (HAQ) (r = 0.58, P < 0.0001), and inversely related to total cholesterol (r = -0.33, P < 0.05) and apolipoprotein A (apoA) (r = -0.58, P < 0.001), but not to oxidative stress markers and ET-1. PWV was similar in RA (median 8.1, range 4.7-16.4 m/s) and SSc (median 8.7, range 7.1-13.1 m/s), but significantly greater (P < 0.01) than controls (median 7.5, range 4.1-10.4 m/s). Aortic PWV was related to log-OPN (r = 0.40, P < 0.01) only in RA patients. It also was related to age (r = 0.34, P < 0.05), mean blood pressure (r = 0.44, P < 0.001), and HAQ (r = 0.48, P < 0.001). In multiple regression analysis (r(2) = 0.36), including confounders, log-OPN remained a significant predictor (P < 0.05) of PWV in RA. Elevated plasma OPN levels are associated with increased arterial stiffness in RA patients, suggesting that this protein might represent a bridge protein between inflammation and the consequent joint damage and cardiovascular risk in RA patients.