Amir Haddad

Is the Madrid Sonographic Enthesitis Index Useful for Differentiating Psoriatic Arthritis from Psoriasis Alone and Healthy Controls

Objective. To assess the usefulness of the MAdrid Sonographic Enthesitis Index (MASEI) in classifying patients as having psoriatic arthritis (PsA) and comparing entheseal abnormalities between patients with PsA, psoriasis alone (PsC), and healthy controls (HC). Methods. Patients with PsC were assessed to exclude inflammatory arthritis. The MASEI scoring system was used to quantify the extent of ultrasonographic (US) entheseal abnormalities. The total MASEI score was categorized into items that reflected inflammatory abnormalities (MASEI-inflammatory) and chronic damage (MASEI-damage). Nonparametric tests were used to compare MASEI scores across the groups. A cutoff point of MASEI ≥ 20 was used to calculate the sensitivity and specificity of the MASEI to classify patients as having PsA. Results. Patients with PsA (n = 50), PsC (n = 66), and HC (n = 60) were assessed. Total MASEI scores were higher in patients with PsA than in those with PsC, and both those groups were higher than HC (p < 0.0001). MASEI-inflammatory showed a similar trend (p < 0.0001). MASEI-damage was higher in patients with PsA compared to both patients with PsC and HC (p < 0.0001); however, no difference was observed between patients with PsC and HC. No significant difference in MASEI scores was found across the 3 groups in patients with a body mass index > 30. The sensitivity of the MASEI score to correctly classify patients as having PsA was 30% and the specificity was 95% when compared to HC and 89% when compared to PsC. Conclusion. The severity of US entheseal abnormalities is highest in patients with PsA followed by PsC and is lowest in healthy controls. MASEI can specifically classify patients as having PsA.

Minimal Disease Activity and Anti–Tumor Necrosis Factor Therapy in Psoriatic Arthritis

A state of minimal disease activity (MDA) was defined and validated as target for treatment in psoriatic arthritis (PsA). We aimed to identify disease characteristics, outcome, and predictors of MDA in patients treated with tumor necrosis factor α (TNFα) blockers.

The Incidence and Risk Factors for Psoriatic Arthritis in Patients With Psoriasis: A Prospective Cohort Study

To estimate the incidence of psoriatic arthritis (PsA) in patients with psoriasis, and to identify risk factors for its development.

Identification and characterization of the adipokinetic hormone/corazonin‐related peptide signaling system in Rhodnius prolixus

The mammalian gonadotropin‐releasing hormone is evolutionarily related to the arthropod adipokinetic hormone and the recently discovered adipokinetic hormone/corazonin‐related peptide (ACP). The function of the ACP signaling system in arthropods is currently unknown. In the present study, we identify and characterize the ACP signaling system in the kissing bug Rhodnius prolixus. We isolated the complete cDNA sequence encoding R. prolixus ACP (Rhopr‐ACP) and examined its expression pattern. Rhopr‐ACP is predominantly expressed in the central nervous system. In particular, it is found in both the brain and corpus cardiacum (CC)/corpora allata (CA) complex. To gain an insight into its role in R. prolixus, we also isolated and functionally characterized cDNA sequences of three splice variants (Rhopr‐ACPR‐A, B and C) encoding R. prolixus ACP G protein‐coupled receptor (Rhopr‐ACPR). Rhopr‐ACPR‐A has only five transmembrane domains, whereas Rhopr‐ACPR‐B and C have all seven domains. Interestingly, Rhopr‐ACPR‐A, B and C were all activated by Rhopr‐ACP, albeit at different sensitivities, when expressed in Chinese hamster ovary cells stably expressing the human G‐protein G16 (CHO/G16). To our knowledge, this is the first study to isolate a truncated receptor cDNA in invertebrates that is functional in a heterologous expression system. Moreover, Rhopr‐ACPR‐B and C but not Rhopr‐ACPR‐A can be coupled with Gq α subunits. Expression profiling indicates that Rhopr‐ACPR is highly expressed in the central nervous system, as well as the CC/CA complex, suggesting that it may control the release of other hormones found in the CC in a manner analogous to gonadotropin‐releasing hormone. Temporal expression profiling shows that both Rhopr‐ACP and Rhopr‐ACPR are upregulated after ecdysis, suggesting that this neuropeptide may be involved in processes associated with post‐ecdysis.

Skin Nontuberculous Mycobacterial Infection in Systemic Lupus Erythematosus: An Unusual Skin Infection Mimicking Lupus Vasculitis

OBJECTIVES To report 2 cases of skin nontuberculous mycobacteria (NTM) occurring in lupus patients and to systematically review the medical literature addressing skin NTM in lupus. METHODS We reported 2 cases of skin NTM in lupus patients followed at the Toronto Lupus Clinic. We conducted a systematic review of the literature on NTM in lupus patients. Ovid Medline (1946 to March 12, 2012) and Embase (1980 to March 12, 2012) were searched for relevant publications. RESULTS Of the 1356 retrieved abstracts, 19 publications were identified and 25 cases of skin NTM were extracted. Skin presentations in this review ranged from papules, plaques, and nodules to ulcerative lesions and abscesses. Skin lesions occurred in the setting of active and inactive lupus and while patients were maintained on steroids and sometimes immunosuppressants. The pathogen species included Mycobacterium chelonae, Mycobacterium haemophilum, Mycobacterium kansasii, Mycobacterium avium, Mycobacterium scrofulaceum, Mycobacterium fortuitum, Mycobacterium marinatum, and Mycobacterium szulgai. The duration of antimycobacterial drugs ranged from 3 to 12 months. Skin excision, drainage, and debridement might be required in some cases. Empirical monotherapy was used initially, and the final choice of antibiotics was based on the susceptibility determined in culture. Overall, the outcomes of the skin lesions resulted in either complete recovery or improvement. CONCLUSIONS A high index of suspicion in lupus patients is required to diagnose NTM, as the initial presentation of NTM can mimic lupus skin manifestations.

Myoinhibitors controlling oviduct contraction within the female blood-gorging insect, Rhodnius prolixus.

Muscle activity can be regulated by stimulatory and inhibitory neuropeptides allowing for contraction and relaxation. There are various families of neuropeptides that can be classified as inhibitors of insect muscle contraction. This study focuses on Rhodnius prolixus and three neuropeptide families that have been shown to be myoinhibitors in insects: A-type allatostatins, myoinhibiting peptides (B-type allatostatins) and myosuppressins. FGLa/AST-like immunoreactive axons and blebs were found on the anterior of the dorsal vessel and on the abdominal nerves. FGLa/AST-like immunoreactive axons were also seen in the trunk nerves and on the bursa. The effects of RhoprAST-2 (FGLa/AST or A-type allatostatins) and RhoprMIP-4 (MIP/AST or B-type allatostatins) were similar, producing dose-dependent inhibition of R. prolixus spontaneous oviduct contractions with a maximum of 70% inhibition and an EC50 at approximately 10(-8)M. The myosuppressin of R. prolixus (RhoprMS) has an unusual FMRFamide C-terminal motif (pQDIDHVFMRFa) as compared to myosuppressins from other insects. Quantitative PCR results show that the RhoprMS receptor transcript is present in adult female oviducts; however, RhoprMS does not have an inhibitory effect on R. prolixus oviduct contractions, but does have a dose-dependent inhibitory effect on the spontaneous contraction of Locusta migratoria oviducts. SchistoFLRFamide, the myosuppressin of Schistocerca gregaria and L. migratoria, also does not inhibit R. prolixus oviduct contractions. This implies that FGLa/ASTs and MIP/ASTs may play a role in regulating egg movement within the oviducts, and that the myosuppressin although myoinhibitory on other muscles in R. prolixus, does not inhibit the contractions of R. prolixus oviducts and may play another role in the reproductive system.

Role of S-Palmitoylation by ZDHHC13 in Mitochondrial function and Metabolism in Liver

Palmitoyltransferase (PAT) catalyses protein S-palmitoylation which adds 16-carbon palmitate to specific cysteines and contributes to various biological functions. We previously reported that in mice, deficiency of Zdhhc13, a member of the PAT family, causes severe phenotypes including amyloidosis, alopecia, and osteoporosis. Here, we show that Zdhhc13 deficiency results in abnormal liver function, lipid abnormalities, and hypermetabolism. To elucidate the molecular mechanisms underlying these disease phenotypes, we applied a site-specific quantitative approach integrating an alkylating resin-assisted capture and mass spectrometry-based label-free strategy for studying the liver S-palmitoylome. We identified 2,190 S-palmitoylated peptides corresponding to 883 S-palmitoylated proteins. After normalization using the membrane proteome with TMT10-plex labelling, 400 (31%) of S-palmitoylation sites on 254 proteins were down-regulated in Zdhhc13-deficient mice, representing potential ZDHHC13 substrates. Among these, lipid metabolism and mitochondrial dysfunction proteins were overrepresented. MCAT and CTNND1 were confirmed to be specific ZDHHC13 substrates. Furthermore, we found impaired mitochondrial function in hepatocytes of Zdhhc13-deficient mice and Zdhhc13-knockdown Hep1–6 cells. These results indicate that ZDHHC13 is an important regulator of mitochondrial activity. Collectively, our study allows for a systematic view of S-palmitoylation for identification of ZDHHC13 substrates and demonstrates the role of ZDHHC13 in mitochondrial function and metabolism in liver.

Functional characterization and expression analysis of the myoinhibiting peptide receptor in the Chagas disease vector, Rhodnius prolixus.

Myoinhibiting peptides (MIPs), which are also known as B-type allatostatins, are a family of neuropeptides found in protostomes. Their primary structure is characterized by an amidated carboxyl-terminal motif consisting of a conserved pair of tryptophan residues normally separated by six non-conserved amino acids (W(X6)Wamide). In the fruit fly Drosophila melanogaster, MIPs are likely the ancestral ligands of the sex peptide receptor, which plays an important role in courtship and reproduction. Recently, several endogenous MIPs were discovered in the Chagas disease vector, Rhodnius prolixus, having both conserved (W(X6)Wamide) and atypical (W(X7)Wamide) carboxyl-terminal motifs. Physiological functions of MIPs are plentiful and include inhibition of visceral muscle activity; a role that has been illustrated on hindgut in R. prolixus. In order to identify novel physiological targets and elucidate biological actions for the MIPs in R. prolixus, we have isolated and examined the spatial expression profile of the MIP receptor transcript in various fifth instar tissues and have additionally determined the expression profile in reproductive tissues of fifth instar as well as adult insects. The most abundant MIP receptor transcript expression was found in the salivary glands and central nervous system, which corroborates roles previously determined for MIPs in other insects. We functionally-characterized the endogenous MIP receptor and examined its activation by R. prolixus MIPs containing the typical W(X6)Wamide and atypical W(X7)Wamide carboxyl-terminal motifs. These peptides dose-dependently activated the MIP receptor (RhoprMIPr1) with EC50 values in the mid-nanomolar range. We also examined the activity of these RhoprMIPs on spontaneous muscle contractions of oviducts from female adult R. prolixus. Our findings confirm the myoinhibitory nature of the MIP peptides, which dose-dependently reduced spontaneous oviduct contractions by nearly 70%, again having mid-nanomolar EC50 values. Finally, we utilized a heterologous receptor assay and oviduct bioassay to examine the activity of several MIP structural analogs, which independently confirmed the requirement of the highly conserved tryptophan residues as well as the amidated C-terminus for retaining full biological activity.

Development and Assessment of Users' Satisfaction with the Systemic Lupus Erythematosus Disease Activity Index 2000 Responder Index-50 Website.

Objective. To describe the development of the Systemic Lupus Erythematosus Disease Activity Index 2000 Responder Index-50 (S2K RI-50) Website (www.s2k-ri-50.com) and to assess satisfaction with its training and examination modules among rheumatologists and rheumatology fellows. Methods. The development of the Website occurred in 3 phases. The first was a deployment phase that consisted of preparing the site map along with its content. The content included the S2K RI-50 training manual, the tests and corresponding question bank, and the online adaptive training module, along with the extensive site testing. The second phase included the participation of rheumatologists and trainees who completed the Website modules. The third was a quality assurance phase in which an online survey was developed to determine the satisfaction level of its users. Further modifications were implemented per participants’ recommendations. Results. The site has been online since it was registered in September 2010. Fourteen rheumatologists and rheumatology trainees from different centers reviewed and completed the material contained in the Website. The survey revealed acceptance among rheumatologists for the Website’s content, design, and presentation. The Website was rated as user-friendly and useful in familiarizing investigators with the S2K RI-50. After completion of the training and examination modules, participants reported a suitable level of preparation to implement the S2K RI-50 in clinical trials and research settings in a timely manner. Conclusion. The Website includes training and examination modules that familiarize rheumatologists with the S2K RI-50 and assesses their competence to use the index. This prepares them for the use of the S2K RI-50 in clinical trials and research settings.

Cyclic Alopecia and Abnormal Epidermal Cornification in Zdhhc13-Deficient Mice Reveal the Importance of Palmitoylation in Hair and Skin Differentiation

Many biochemical pathways involved in hair and skin development have not been investigated. Here, we reported on the lesions and investigated the mechanism underlying hair and skin abnormalities in Zdhhc13(skc4) mice with a deficiency in DHHC13, a palmitoyl-acyl transferase encoded by Zdhhc13. Homozygous affected mice showed ragged and dilapidated cuticle of the hair shaft (CUH, a hair anchoring structure), poor hair anchoring ability, and premature hair loss at early telogen phase of the hair cycle, resulting in cyclic alopecia. Furthermore, the homozygous affected mice exhibited hyperproliferation of the epidermis, disturbed cornification, fragile cornified envelope (CE, a skin barrier structure), and impaired skin barrier function. Biochemical investigations revealed that cornifelin, which contains five palmitoylation sites at cysteine residues (C58, C59, C60, C95, and C101), was a specific substrate of DHHC13 and that it was absent in the CUH and CE structures of the affected mice. Furthermore, cornifelin levels were markedly reduced when two palmitoylated cysteines were replaced with serine (C95S and C101S). Taken together, our results suggest that DHHC13 is important for hair anchoring and skin barrier function and that cornifelin deficiency contributes to cyclic alopecia and skin abnormalities in Zdhhc13(skc4) mice.