The lipophilic cyclic peptide cyclosporin A induces aggregation of gel-forming mucins

Cyclic peptides are good candidates for orally delivered therapeutics, however, issues remain in their development due to low intestinal permeability. Although some of the biological factors have been reported that regulate intestinal permeation of cyclic peptides, the influence of the mucus barrier, a major hurdle to epithelial drug delivery, on cyclic peptide bioavailability is unclear. In this study, we show that the lipophilic cyclic peptide, cyclosporin A (CsA), interacted with, and likely induced aggregation, of polymeric, gel-forming mucins (MUC2, MUC5AC and MUC5B) which underpin the mucus gel-networks in the gastrointestinal tract. Under similar conditions, two other cyclic peptides (daptomycin and polymyxin B) did not cause mucin aggregation. Using rate-zonal centrifugation, purified MUC2, MUC5AC and MUC5B mucins sedimented faster in the presence of CsA, with a significant increase in mucins in the pellet fraction. In contrast, mucin sedimentation profiles were largely unaltered after treatment with daptomycin or polymyxin B. CsA increased MUC5B sedimentation was concentration-dependent, and sedimentation studies using recombinant mucin protein domains suggests CsA most likely causes aggregation of the relatively non-O-glycosylated N-terminal and C-terminal regions of MUC5B. Furthermore, the aggregation of the N-terminal region, but not the C-terminal region, was affected by pH. CsA has partially N-methylated amide groups, this unique molecular structure, not present in daptomycin and polymyxin B, may potentially be involved in interaction with gel-forming mucin. Taken together, our results indicate that the interaction of gel-forming mucins with the cyclic peptide CsA is mediated at the N- and C-terminal domains of mucin polymers under physiological conditions. Our findings demonstrate that the mucus barrier is an important physiological factor regulating the intestinal permeation of cyclic peptides in vivo.

Defining the early stages of intestinal colonisation by whipworms

Whipworms are large metazoan parasites that inhabit multi-intracellular epithelial tunnels in the large intestine of their hosts, causing chronic disease in humans and other mammals. How first-stage larvae invade host epithelia and establish infection remains unclear. Here we investigate early infection events using both Trichuris muris infections of mice and murine caecaloids, the first in-vitro system for whipworm infection and organoid model for live helminths. We show that larvae degrade mucus layers to access epithelial cells. In early syncytial tunnels, larvae are completely intracellular, woven through multiple live dividing cells. Using single-cell RNA sequencing of infected mouse caecum, we reveal that progression of infection results in cell damage and an expansion of enterocytes expressing of Isg15, potentially instigating the host immune response to the whipworm and tissue repair. Our results unravel intestinal epithelium invasion by whipworms and reveal specific host-parasite interactions that allow the whipworm to establish its multi-intracellular niche.

Whipworms are large parasites causing chronic disease in humans and other mammals. Here, the authors show how larvae create tunnels inside the gut lining and reveal the early host response to infection via Isg15 in mice and murine caecaloids.

Assembly and organization of the N-terminal region of mucin MUC5AC: Indications for structural and functional distinction from MUC5B

Elevated levels of MUC5AC, one of the major gel-forming mucins in the lungs, are closely associated with chronic obstructive lung diseases such as chronic bronchitis and asthma. It is not known, however, how the structure and/or gel-making properties of MUC5AC contribute to innate lung defense in health and drive the formation of stagnant mucus in disease. To understand this, here we studied the biophysical properties and macromolecular assembly of MUC5AC compared to MUC5B. To study each native mucin, we used Calu3 monomucin cultures that produced MUC5AC or MUC5B. To understand the macromolecular assembly of MUC5AC through N-terminal oligomerization, we expressed a recombinant whole N-terminal domain (5ACNT). Scanning electron microscopy and atomic force microscopy imaging indicated that the two mucins formed distinct networks on epithelial and experimental surfaces; MUC5B formed linear, infrequently branched multimers, whereas MUC5AC formed tightly organized networks with a high degree of branching. Quartz crystal microbalance-dissipation monitoring experiments indicated that MUC5AC bound significantly more to hydrophobic surfaces and was stiffer and more viscoelastic as compared to MUC5B. Light scattering analysis determined that 5ACNT primarily forms disulfide-linked covalent dimers and higher-order oligomers (i.e., trimers and tetramers). Selective proteolytic digestion of the central glycosylated region of the full-length molecule confirmed that MUC5AC forms dimers and higher-order oligomers through its N terminus. Collectively, the distinct N-terminal organization of MUC5AC may explain the more adhesive and unique viscoelastic properties of branched, highly networked MUC5AC gels. These properties may generate insight into why/how MUC5AC forms a static, "tethered" mucus layer in chronic muco-obstructive lung diseases.

Mucus

Mucus is a slimy hydrogel that lines the mucosal surfaces in our body, including the intestines, stomach, eyes, lungs and urogenital tract. This glycoprotein-rich network is truly the jack of all trades. As a barrier, it lubricates surfaces, protects our cells from physical stress, and selectively allows the passage of nutrients while clearing out pathogens and debris. As a home to our microbiota, it supports a level of microbial diversity that is unattainable with most culture methods. As a reservoir of complex carbohydrate structures called glycans, it plays critical roles in controlling cell adhesion and signaling, and it alters the behavior and spatial distribution of microbes. On top of all this, mucus regulates the passage of sperm during fertilization, heals wounds, helps us smell, and prevents the stomach from digesting itself, to name just a few of its functions. Given these impressive features, it is no wonder that mucus crosses boundaries of species and kingdoms - mucus gels are made by organisms ranging from the simplest metazoans to corals, snails, fish, and frogs. It is also no surprise that mucus is exploited in everyday applications, including foods, cosmetics, and other products relevant to medicine and industry.

The MUC5B mucin polymer is dominated by repeating structural motifs and its topology is regulated by calcium and pH

The polymeric mucin MUC5B provides the structural and functional framework of respiratory mucus, conferring both viscoelastic and antimicrobial properties onto this vital protective barrier. Whilst it is established that MUC5B forms disulfide-linked linear polymers, how this relates to their packaging in secretory granules, and their molecular form in mucus remain to be fully elucidated. Moreover, the role of the central heavily O-glycosylated mucin domains in MUC5B conformation is incompletely described. Here we have completed a detailed structural analysis on native MUC5B polymers purified from saliva and subsequently investigated how MUC5B conformation is affected by changes in calcium concentration and pH, factors important for mucin intragranular packaging and post-secretory expansion. The results identify that MUC5B has a beaded structure repeating along the polymer axis and suggest that these repeating motifs arise from distinct glycosylation patterns. Moreover, we demonstrate that the conformation of these highly entangled linear polymers is sensitive to calcium concentration and changes in pH. In the presence of calcium (Ca²⁺, 10 mM) at pH 5.0, MUC5B adopted a compact conformation which was lost either upon removal of calcium with EGTA, or by increasing the pH to 7.4. These results suggest a pathway of mucin collapse to enable intracellular packaging and mechanisms driving mucin expansion following secretion. They also point to the importance of the tight control of calcium and pH during different stages of mucin biosynthesis and secretion, and in the generation of correct mucus barrier properties.

The C-terminal dimerization domain of the respiratory mucin MUC5B functions in mucin stability and intracellular packaging before secretion

Mucin 5B (MUC5B) has an essential role in mucociliary clearance that protects the pulmonary airways. Accordingly, knowledge of MUC5B structure and its interactions with itself and other proteins is critical to better understand airway mucus biology and improve the management of lung diseases such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD). The role of an N-terminal multimerization domain in the supramolecular organization of MUC5B has been previously described, but less is known about its C-terminal dimerization domain. Here, using cryogenic electron microscopy (cryo-EM) and small-angle X-ray scattering (SAXS) analyses of recombinant disulfide-linked dimeric MUC5B dimerization domain we identified an asymmetric, elongated twisted structure, with a double globular base. We found that the dimerization domain is more resistant to disruption than the multimerization domain suggesting the twisted structure of the dimerization domain confers additional stability to MUC5B polymers. Size-exclusion chromatography-multiangle light scattering (SEC-MALS), SPR-based biophysical analyses and microscale thermophoresis of the dimerization domain disclosed no further assembly, but did reveal reversible, calcium-dependent interactions between the dimerization and multimerization domains that were most active at acidic pH, suggesting that these domains have a role in MUC5B intragranular organization. In summary, our results suggest a role for the C-terminal dimerization domain of MUC5B in compaction of mucin chains during granular packaging via interactions with the N-terminal multimerization domain. Our findings further suggest that the less stable multimerization domain provides a potential target for mucin depolymerization to remove mucus plugs in COPD and other lung pathologies.

Effective communication with older people

Effective communication with older people is an important aspect of nursing practice. Ineffective communication can lead to older people feeling inadequate, disempowered and helpless. Nurses have a duty to ensure that older people think they are being listened to and that their concerns are being validated in a non-judgemental way. Central to effective communication is the ability of nurses to be self-aware, and monitor their thoughts and feelings about, for example, negative stereotypes associated with the ageing process. Effective communication can sometimes be difficult to achieve due to the effects of ageing, but nurses can overcome some barriers through thoughtful interventions. It is important to treat older people as individuals, and to monitor and adapt communication accordingly. By doing so, nurses can ensure older people feel empowered, respected and able to maintain their independence.

Granule-stored MUC5B mucins are packed by the non-covalent formation of N-terminal head-to-head tetramers

Most MUC5B mucin polymers in the upper airways of humans and pigs are produced by submucosal glands. MUC5B forms N-terminal covalent dimers that are further packed into larger assemblies because of low pH and high Ca2+ in the secretory granule of the mucin-producing cell. We purified the recombinant MUC5B N-terminal covalent dimer and used single-particle electron microscopy to study its structure under intracellular conditions. We found that, at intragranular pH, the dimeric MUC5B organized into head-to-head noncovalent tetramers where the von Willebrand D1-D2 domains hooked into each other. These N-terminal tetramers further formed long linear complexes from which, we suggest, the mucin domains and their C termini project radially outwards. Using conventional and video microscopy, we observed that, upon secretion into the submucosal gland ducts, a flow of bicarbonate-rich fluid passes the mucin-secreting cells. We suggest that this unfolds and pulls out the MUC5B assemblies into long linear threads. These further assemble into thicker mucin bundles in the glandular ducts before emerging at the gland duct opening. We conclude that the combination of intracellular packing of the MUC5B mucin and the submucosal gland morphology creates an efficient machine for producing linear mucin bundles.

MUB40 Binds to Lactoferrin and Stands as a Specific Neutrophil Marker

Neutrophils represent the most abundant immune cells recruited to inflamed tissues. A lack of dedicated tools has hampered their detection and study. We show that a synthesized peptide, MUB₄₀, binds to lactoferrin, the most abundant protein stored in neutrophil-specific and tertiary granules. Lactoferrin is specifically produced by neutrophils among other leukocytes, making MUB₄₀ a specific neutrophil marker. Naive mammalian neutrophils (human, guinea pig, mouse, rabbit) were labeled by fluorescent MUB₄₀ conjugates (-Cy5, Dylight405). A peptidase-resistant retro-inverso MUB₄₀ (RI-MUB₄₀) was synthesized and its lactoferrin-binding property validated. Neutrophil lactoferrin secretion during in vitro Shigella infection was assessed with RI-MUB₄₀-Cy5 using live cell microscopy. Systemically administered RI-MUB₄₀-Cy5 accumulated at sites of inflammation in a mouse arthritis inflammation model in vivo and showed usefulness as a potential tool for inflammation detection using non-invasive imaging. Improving neutrophil detection with the universal and specific MUB₄₀ marker will aid the study of broad ranges of inflammatory diseases.

Health Visiting: Preparation for Practice (Fourth edition) Luker Karen McHugh Gretl and Bryar Rosamund Health Visiting: Preparation for Practice (Fourth edition) 312pp £32.99 Wiley Blackwell 9781119078586 111907858X [Formula: see text]

Children, families and the communities they live in deserve high-quality care from well-informed health visitors and healthcare staff. Having an understanding of the role and responsibilities of health visitors and the wider influences on their practice has never been more important.

Occupational Therapy and Multidisciplinary Working on Acute Psychiatric Wards: The Tompkins Acute Ward Study

There is limited research into occupational therapy and interprofessional working on acute psychiatric wards. This study aimed to explore relations between occupational therapists and other members of the multidisciplinary team through structured interviews with 47 staff on 14 acute psychiatric wards.

The study found that occupational therapists provided assessments, group activities and individual therapeutic work, with the assessment and development of activities of daily living being central. Linking patients with community resources in preparation for discharge was also important. Severity of illness among patients and speed of discharge were barriers to effective input. Nurses and psychiatrists appreciated occupational therapy input but rarely the breadth of the role. Multidisciplinary relations were generally positive, although some ward teams were disinclined to include occupational therapists in communications and decision making. The occupational therapists appreciated their professional knowledge and opinion being respected and considered.

The study concluded that occupational therapists play an important if often misunderstood role on acute psychiatric wards, but that their involvement could be significantly increased through the employment of more experienced occupational therapists and the provision of interprofessional education. Further research is required to explore the facilities, resources and support required to maximise occupational therapy input and identify areas for increased interprofessional working.

We need to inspire students

The 1914 message 'Your Country Needs You' was an attempt to attract recruits to the military. The message has resonance for nursing today. Imagine answering the call full of enthusiasm but then being asked by a senior colleague: 'What do you want to come into nursing for?'

Biosynthesis of the polymeric gel-forming mucin MUC5B

MUC5B is a major polymeric mucin in the airway mucus gel and is an essential component of innate defense of the respiratory epithelium. Knowledge of the synthesis and intracellular processing of MUC5B is incomplete. We investigated the molecular details of MUC5B assembly in primary human bronchial epithelial cells (HBECs) grown at an air-liquid interface (ALI). Electrophoretic and centrifugal separations of intracellular forms of MUC5B probed with antibodies specific for non-O-glycosylated and O-glycosylated forms of the mucin identified three major intracellular populations of MUC5B (non-O-glycosylated monomer and dimer, and O-glycosylated polymers). Biophysical analysis of recombinant MUC5B COOH-terminus (CT5B; D4-B-C-CK) expressed in 293-EBNA cells showed that MUC5B dimerizes by disulfide linkage. Pulse-chase studies in the HBEC ALI cultures showed that non-O-glycosylated MUC5B was synthesized within 20 min of metabolic labeling and O-glycosylated, polymeric mucin within 2 h. Radiolabeled O-glycosylated mucin polymers were secreted within 2 h and the majority were released by 48 h. These data indicate that MUC5B follows a similar assembly to the related glycoprotein, von Willebrand factor (vWF); however, unlike vWF the MUC5B polypeptide shows no evidence of major proteolytic processing of D-domains during the production of the mature secreted polymeric mucin in normal and cystic fibrosis (CF) primary bronchial epithelial cells. In contrast, MUC5B D-domains were modified by neutrophil elastase, a protease commonly found in CF sputum, demonstrating that proteolytic degradation of MUC5B is an extracellular event in CF sputum. These results define the pathway for synthesis of MUC5B in primary human goblet cells.

Assembly of the respiratory mucin MUC5B: a new model for a gel-forming mucin

Mucins are essential components in mucus gels that form protective barriers at all epithelial surfaces, but much remains unknown about their assembly, intragranular organization, and post-secretion unfurling to form mucus. MUC5B is a major polymeric mucin expressed by respiratory epithelia, and we investigated the molecular mechanisms involved during its assembly. Studies of intact polymeric MUC5B revealed a single high affinity calcium-binding site, distinct from multiple low affinity sites on each MUC5B monomer. Self-diffusion studies with intact MUC5B showed that calcium binding at the protein site catalyzed reversible cross-links between MUC5B chains to form networks. The site of cross-linking was identified in the MUC5B D3-domain as it was specifically blocked by D3 peptide antibodies. Biophysical analysis and single particle EM of recombinant MUC5B N terminus (D1D2D'D3; NT5B) and subdomains (D1, D1-D2, D2-D'-D3, and D3) generated structural models of monomers and disulfide-linked dimers and suggested that MUC5B multimerizes by disulfide linkage between D3-domains to form linear polymer chains. Moreover, these analyses revealed reversible homotypic interactions of NT5B at low pH and in high calcium, between disulfide-linked NT5B dimers, but not monomers. These results enable a model of MUC5B to be derived, which predicts mechanisms of mucin intracellular assembly and storage, which may be common to the other major gel-forming polymeric mucins.

Cystic fibrosis: an inherited disease affecting mucin-producing organs

Our current understanding of cystic fibrosis (CF) has revealed that the biophysical properties of mucus play a considerable role in the pathogenesis of the disease in view of the fact that most mucus-producing organs are affected in CF patients. In this review, we discuss the potential causal relationship between altered cystic fibrosis transmembrane conductance regulator (CFTR) function and the production of mucus with abnormal biophysical properties in the intestine and lungs, highlighting what has been learned from cell cultures and animal models that mimic CF pathogenesis. A similar cascade of events, including mucus obstruction, infection and inflammation, is common to all epithelia affected by impaired surface hydration. Hence, the main structural components of mucus, namely the polymeric, gel-forming mucins, are critical to the onset of the disease. Defective CFTR leads to epithelial surface dehydration, altered pH/electrolyte composition and mucin concentration. Further, it can influence mucin transition from the intracellular to extracellular environment, potentially resulting in aberrant mucus gel formation. While defective HCO3(-) production has long been identified as a feature of CF, it has only recently been considered as a key player in the transition phase of mucins. We conclude by examining the influence of mucins on the biophysical properties of CF sputum and discuss existing and novel therapies aimed at removing mucus from the lungs. This article is part of a Directed Issue entitled: Cystic Fibrosis: From o-mics to cell biology, physiology, and therapeutic advances.

The experiences of nursing students with dyslexia

AIM

To explore the experiences of pre-registration nursing students with dyslexia at one university.

METHOD

Qualitative methodology was used and semi-structured interviews were carried out with a convenience sample of seven students with formally diagnosed dyslexia. Data were analysed using a thematic network approach.

FINDINGS

Fear of ridicule and discrimination exist for nursing students with dyslexia, and delays in identification, referral and testing may adversely affect learning. A sense of duty to disclose dyslexia is linked to students' determination to safeguard those in their care, although there is confusion about the nature of disclosure by the university to lecturers and practice colleagues. Students are acutely self-aware although not all feel disabled by dyslexia. Requirements for support relate to personal attributes, knowledge and perception. A perceived lack of caring in the profession for nurses with dyslexia is of concern.

CONCLUSION

Early diagnosis of dyslexia enables the provision of appropriate support. Support should be tailored to individuals' needs. Disclosure can cause anxiety, and the attitude of educators and clinical colleagues towards students with dyslexia affects students' experiences. Students with dyslexia are aware of their professional responsibilities. Professional and legislative guidance provides information for those working with students who have a disability.

Structural effects of fibulin 5 missense mutations associated with age-related macular degeneration and cutis laxa

PURPOSE

AMD has a complex etiology with environmental and genetic risk factors. Ten fibulin 5 sequence variants have been associated with AMD and two other fibulin 5 mutations cause autosomal-recessive cutis laxa. Fibulin 5 is a 52-kDa calcium-binding epidermal growth factor (cbEGF)-rich extracellular matrix protein that is essential for the formation of elastic tissues. Biophysical techniques were used to detect structural changes in the fibulin 5 mutants and to determine whether changes are predictive of pathogenicity.

METHODS

Native PAGE, nonreduced SDS-PAGE, size-exclusion column multiangle laser light scattering, sedimentation velocity, and circular dichroism (CD) were used to investigate the mobility, hydrodynamic radii, folding, and oligomeric states of the fibulin 5 mutants in the absence and presence of Ca(2+).

RESULTS

CD showed that all mutants are folded, although perturbations to secondary structure contents were detected. Both cutis laxa mutants increased dimerization. Most other mutants slightly increased self-association in the absence of Ca(2+) but this was also demonstrated by G202R, a polymorphism detected in a control individual. The AMD-associated mutant G412E showed lower-than-expected mobility during native-PAGE, the largest hydrodynamic radius for the monomer form and the highest levels of aggregation in both the absence and presence of Ca(2+).

CONCLUSIONS

The results identified structural differences for the disease-causing cutis laxa mutants and for one AMD variant (G412E), suggesting that this may also be pathogenic. Although the other AMD-associated mutants showed no gross structural differences, they cannot be excluded as pathogenic by differences outside the scope of this study-for example, disruption of heterointeractions.

Fibulin 5 forms a compact dimer in physiological solutions

Fibulin 5 is a 52-kDa calcium-binding epidermal growth factor (cbEGF)-rich extracellular matrix protein that is essential for the formation of elastic tissues. Missense mutations in fibulin 5 cause the elastin disorder cutis laxa and have been associated with age-related macular degeneration, a leading cause of blindness. We investigated the structure, hydrodynamics, and oligomerization of fibulin 5 using small angle x-ray scattering, EM, light scattering, circular dichroism, and sedimentation. Compact structures for the monomer were determined by small angle x-ray scattering and EM, and are supported by close agreement between the theoretical sedimentation of the structures and the experimental sedimentation of the monomer in solution. EM showed that monomers associate around a central cavity to form a dimer. Light scattering and equilibrium sedimentation demonstrated that the equilibrium between the monomer and the dimer is dependent upon NaCl and Ca2+ concentrations and that the dimer is dominant under physiological conditions. The dimerization of fragments containing just the cbEGF domains suggests that intermolecular interactions between cbEGFs cause dimerization of fibulin 5. It is possible that fibulin 5 functions as a dimer during elastinogenesis or that dimerization may provide a method for limiting interactions with binding partners such as tropoelastin.

Differential regulation of elastic fiber formation by fibulin-4 and -5

Fibulin-4 and -5 are extracellular glycoproteins with essential non-compensatory roles in elastic fiber assembly. We have determined how they interact with tropoelastin, lysyl oxidase, and fibrillin-1, thereby revealing how they differentially regulate assembly. Strong binding between fibulin-4 and lysyl oxidase enhanced the interaction of fibulin-4 with tropoelastin, forming ternary complexes that may direct elastin cross-linking. In contrast, fibulin-5 did not bind lysyl oxidase strongly but bound tropoelastin in terminal and central regions and could concurrently bind fibulin-4. Both fibulins differentially bound N-terminal fibrillin-1, which strongly inhibited their binding to lysyl oxidase and tropoelastin. Knockdown experiments revealed that fibulin-5 controlled elastin deposition on microfibrils, although fibulin-4 can also bind fibrillin-1. These experiments provide a molecular account of the distinct roles of fibulin-4 and -5 in elastic fiber assembly and how they act in concert to chaperone cross-linked elastin onto microfibrils.

Notch3 activation modulates cell growth behaviour and cross-talk to Wnt/TCF signalling pathway

Notch3 is one of the four Notch receptors identified in mammal and expressed mainly in the arterial smooth muscle cells of human adult. Signalling via Notch3 is thought to be important in maintaining the phenotypic stability of the cells, but the nature of the signalling and its regulation to other signalling pathways are largely unknown. To understand further of the cellular function of Notch3 signalling, we generated cell lines stably expressing a constitutively active form of human Notch3 comprising of its soluble intracellular domain (N3IC). The N3IC expressing cells showed accelerated proliferation, decreased migration, increased cell surface N-cadherin, and growth in a colonised fashion that was reversible by N-cadherin blockade. N3IC expressing cells were also protected significantly against staurosporine-induced apoptosis and exhibited lower caspase 3/7 activity, accompanied by up-regulation of pAKT compared to control cells. We also found a complex cross-talk between Notch3 signalling and the Wnt pathway. N3IC stimulated Wnt-independent T-cell factor (TCF, the target transcription factor in the Wnt pathway) activation which was associated with increased Tyr-142 phosphorylation of beta-catenin. In contrast N3IC suppressed TCF activation in response to LiCl, which mimics the Wnt-dependent TCF activation mechanism. We conclude that Notch3 promotes cell growth and survival by activating PI3-kinase/AKT pathway; N-cadherin participates in the change of cell growth caused by Notch3 activation; and Notch3 signalling has dual-effects on the Wnt/TCF pathway suggesting a buffering role that Notch3 signalling may play in balancing these two important signalling pathways in regulating cell function.

Reduced secretion of fibulin 5 in age-related macular degeneration and cutis laxa

Age-related macular degeneration (ARMD) is the leading cause of irreversible visual loss in the Western world, affecting approximately 25 million people worldwide. The pathogenesis is complex and missense mutations in FBLN5 have been reported in association with ARMD. We have investigated the role of fibulin 5 in ARMD by completing the first European study of the gene FBLN5 in ARMD (using 2 European cohorts of 805 ARMD patients and 279 controls) and by determining the functional effects of the missense mutations on fibulin 5 expression. We also correlated the FBLN5 genotype with the ARMD phenotype. We found two novel sequence changes in ARMD patients that were absent in controls and expressed these and the other nine reported FBLN5 mutations associated with ARMD and two associated with the autosomal recessive disease cutis laxa. Fibulin 5 secretion was significantly reduced (P<0.001) for four ARMD (p.G412E, p.G267S, p.I169 T, and p.Q124P) and two cutis laxa (p.S227P, p.C217R) mutations. These results suggest that some missense mutations associated with ARMD lead to decreased fibulin 5 secretion with a possible corresponding reduction in elastinogenesis. This study confirms the previous work identifying an association between FBLN5 mutations and ARMD and for the first time suggests a functional mechanism by which these mutations can lead to ARMD. It further demonstrates that FBLN5 mutations can be associated with different phenotypes of ARMD (not limited to the previously described cuticular drusen type). Such knowledge may ultimately lead to the development of novel therapies for this common disease.

Reflex tics in two patients with Gilles de la Tourette syndrome

Two patients with Gilles de la Tourette syndrome (GTS) showed tics triggered by external stimuli. This unusual feature is of significance to the aetiology of GTS and in particular the relationship between GTS and the startle response.