Aquaglyceroporins and orthodox aquaporins in human adipocytes.

Aquaporins play a crucial role in water homeostasis in the human body, and recently the physiological importance of aquaporins as glycerol channels have been demonstrated. The aquaglyceroporins (AQP3, AQP7, AQP9 and AQP10) represent key glycerol channels, enabling glycerol flux across the membranes of cells. Adipocytes are the major source of glycerol and during lipolysis, glycerol is released to be metabolized by other tissues through a well-orchestrated process. Here we show that both AQP3 and AQP7 bind to the lipid droplet protein perilipin 1 (PLIN1), suggesting that PLIN1 is involved in the coordination of the subcellular translocation of aquaglyceroporins in human adipocytes. Moreover, in addition to aquaglyceroporins, we discovered by transcriptome sequencing that AQP1 is expressed in human primary adipocytes. AQP1 is mainly a water channel and thus is thought to be involved in the response to hyper-osmotic stress by efflux of water during hyperglycemia. Thus, this data suggests a contribution of both orthodox aquaporin and aquaglyceroporin in human adipocytes to maintain the homeostasis of glycerol and water during fasting and feeding.

Internet-Delivered Cognitive Behavior Therapy for Atopic Dermatitis: A Randomized Clinical Trial.

IMPORTANCE: Atopic dermatitis is a common and debilitating skin condition characterized by intense itching and chronic inflammation. Research on behavioral treatments with high accessibility is needed. OBJECTIVE: To investigate the efficacy of a highly scalable internet-delivered cognitive behavior therapy (CBT) for adults with atopic dermatitis. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial from a medical university in Stockholm, Sweden, included 102 adults with atopic dermatitis, recruited from across Sweden, who received 12 weeks of internet-delivered CBT (March 29, 2017, to February 16, 2018). The first participant provided screening data on November 27, 2016, and the last 1-year follow-up assessment was conducted on June 28, 2019. INTERVENTIONS: Participants were randomized in a 1:1 ratio to 12 weeks of therapist-guided internet-delivered CBT (n = 51) or a control condition (n = 51) that gave instructions about standard care. MAIN OUTCOMES AND MEASURES: The primary outcome was the between-group difference in mean reduction of atopic dermatitis symptoms as measured by the Patient-Oriented Eczema Measure and modeled intention to treat during the 12-week treatment period. RESULTS: A total of 102 participants (mean [SD] age, 37 [11] years; 83 [81%] female) were recruited and randomized. The primary analysis indicated that participants receiving internet-delivered CBT, relative to the controls, had a significantly larger mean weekly reduction in symptoms of atopic dermatitis as measured with the Patient-Oriented Eczema Measure (B = 0.32; 95% CI, 0.14-0.49; P < .001), with a moderate to large, controlled effect size after treatment (d = 0.75; 95% CI, 0.32-1.16). Secondary analyses indicated that internet-delivered CBT also produced significantly larger reductions in itch intensity, perceived stress, sleep problems, and depression. Gains were sustained at 12 months of follow-up. Treatment satisfaction was high, and therapists spent a mean (SD) of 39.7 (34.7) minutes per treated patient providing internet-delivered CBT. CONCLUSIONS AND RELEVANCE: Internet-delivered CBT appears to be efficacious for reducing symptoms of atopic dermatitis, despite requiring minimal therapist resources. Thus, internet-delivered CBT has the potential to increase access to effective adjunct behavioral treatment for patients with this common skin condition. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03051958.

The effect of picture support on narrative retells in Swedish adolescents with ADHD.

ADHD is characterized by executive functioning (EF) deficits, which in turn may affect language, and therefore EF demands in language assessment tasks are important to consider. This study aims to inform clinical practice by 1) comparing and describing narrative retells in Swedish adolescents with and without ADHD, and 2) investigating the effects of picture support on narration in the two groups. Fifteen adolescents with ADHD and 31 with typical development (TD) participated. Two carefully matched narratives for retelling, one with and one without picture support were administered, transcribed, and analyzed regarding content and linguistic complexity (macro- and microlevel measures). The results showed that the ADHD group included less content than the TD group in both tasks, measured in fewer story grammar units and details. Both groups included more story grammar units in the task without picture support. The TD group had shorter retells with higher syntactic complexity in the task with picture support compared to the task without picture support. Compared to TD peers, retells without picture support from the ADHD group were significantly shorter and had a higher proportion of grammatical errors. These results show different strengths and weaknesses in the two groups and indicate that the narrative task without picture support, which places higher demands on EF, captured a linguistic vulnerability in the ADHD group. In conclusion, the choice of narrative task is important to consider in clinical practice to enable accurate descriptions of linguistic strengths and weaknesses in individuals with ADHD, and aid in differential diagnosis.

Worse health status, sleeping problems, and anxiety in 16-year-old students are associated with chronic musculoskeletal pain at three-year follow-up.

BACKGROUND: Chronic musculoskeletal pain is common in adolescents, and it has been shown that adolescents with pain may become young adults with pain. Pain often coincides with psychosomatic symptoms in adults, but little is known about longitudinal associations and predictors of pain in adolescents. The aim was to investigate chronic musculoskeletal pain and its associations with health status, sleeping problems, stress, anxiety, depression, and physical activity in 16-year-old students at baseline, and to identify risk factors using a three-year follow-up. METHODS: This was a longitudinal study of 256 students attending a Swedish upper secondary school. Questionnaires regarding chronic musculoskeletal pain and distribution of pain (mannequin), health status (EQ-5D-3 L), sleeping problems (Uppsala Sleep Inventory), stress symptoms (single-item question), anxiety and depression (Hospital Anxiety and Depression Scale), and physical activity (International Physical Activity Questionnaire) were issued at baseline and follow-up. Student's t-test and chi2 test were used for descriptive statistics and logistic regression analyses were used to study associations between chronic pain and independent variables. RESULTS: Fifty-two out of 221 students at baseline (23.5%) and 39 out of 154 students at follow-up (25.3%) were categorized as having chronic musculoskeletal pain. Chronic musculoskeletal pain at follow-up was separately associated with reporting of an EQ-5D value below median (OR 4.06, 95% CI 1.83-9.01), severe sleeping problems (OR 3.63, 95% CI 1.69-7.82), and possible anxiety (OR 4.19, 95% CI 1.74-10.11) or probable anxiety (OR 3.82, 95% CI 1.17-12.48) at baseline. Similar results were found for associations between chronic musculoskeletal pain and independent variables at baseline. In multiple logistic regression analysis, chronic musculoskeletal pain at baseline was a predictor of chronic musculoskeletal pain at follow-up (OR 2.99, 95% CI 1.09-8.24, R2 = 0.240). CONCLUSION: Chronic musculoskeletal pain at baseline was the most important predictor for reporting chronic musculoskeletal pain at the three-year follow-up, but a worse health status, severe sleeping problems, and anxiety also predicted persistence or development of chronic musculoskeletal pain over time. Interventions should be introduced early on by the school health services to promote student health.

Exposure-based cognitive behavior therapy for atopic dermatitis: an open trial.

Atopic dermatitis (AD) is a common and debilitating inflammatory dermatological disorder and is marked by itch and inflamed skin. Scratching, sleep loss, and avoidance of situations associated with more AD symptoms are central hypothesized mechanisms that perpetuate the disorder and cause reduced quality of life. We developed an exposure-based cognitive behavioral treatment (CBT) that entailed mindfulness practice as a means to increase tolerance for aversive experiences during exposure. The aim of the present study was to test the treatment's acceptability and preliminary efficacy in adults with AD. We used an uncontrolled pretest-posttest design and recruited participants (N = 9) from a university hospital dermatological clinic. The treatment comprised 10 weekly sessions over 10 weeks and assessments of AD symptoms as well as psychiatric symptoms and quality of life were conducted at baseline, posttreatment and 6-month follow-up. The results showed significant and large baseline to posttreatment improvements on self-reported measures of AD symptoms (p = .020) and general anxiety (p = .005), but there was no significant improvement in depression or quality of life. Treatment satisfaction was high and a majority of participants (67%) completed the treatment. We conclude that exposure-based CBT for adult AD can be feasible, acceptable, and potentially efficacious.

Is 'legal empowerment of the poor' relevant to people with disabilities in developing countries? An empirical and normative review.

BACKGROUND: Legal empowerment of the poor is highly relevant to public health as it aims to relieve income poverty, a main determinant of health. The Commission on Legal Empowerment of the Poor (CLEP) has proposed legal empowerment measures in the following four domains: access to justice and the rule of law, property, labor, and business rights. Despite being overrepresented among the poor, CLEP has not explicitly considered the situation of people with disabilities. OBJECTIVES: To examine the empirical evidence for the relevance of the CLEP legal empowerment measures to people with disabilities in low- and lower middle-income countries, and to evaluate the extent to which the Convention on the Rights of Persons with Disabilities (CRPD) addresses those measures. METHODS: Critical literature review of empirical studies and a checklist assessment of the CRPD. RESULTS: Fourteen included articles confirm that people with disabilities experience problems in the domains of access to justice and the rule of law, labor rights, and business rights. No texts on property rights were found. Evidence for the effectiveness of the proposed measures is insufficient. Overall, the CRPD fully or partially supports two-thirds of the proposed measures (seven out of nine measures for access to justice and the rule of law, none of the five measures for property rights, all seven measures for labor rights, and six out of nine measures for business rights). CONCLUSIONS: Although most of the domains of the CLEP legal empowerment measures are relevant to people with disabilities from both empirical and normative perspectives, it is uncertain whether the devised measures are of immediate relevance to them. Further research is warranted in this regard.

Complement-activating IgM enhances the humoral but not the T cell immune response in mice.

IgM antibodies specific for a certain antigen can enhance antibody responses when administered together with this antigen, a process believed to require complement activation by IgM. However, recent data show that a knock-in mouse strain, Cµ13, which only produces IgM unable to activate complement, has normal antibody responses. Moreover, the recently discovered murine IgM Fc receptor (FcµR or TOSO/FAIM3) was shown to affect antibody responses. This prompted the re-investigation of whether complement activation by specific IgM is indeed required for enhancement of antibody responses and whether the mutation in Cµ13 IgM also caused impaired binding to FcµR. The results show that IgM from Cµ13 and wildtype mice bound equally well to the murine FcµR. In spite of this, specific Cµ13 IgM administered together with sheep red blood cells or keyhole limpet hemocyanine was a very poor enhancer of the antibody and germinal center responses as compared with wildtype IgM. Within seconds after immunization, wildtype IgM induced deposition of C3 on sheep red blood cells in the blood. IgM which efficiently enhanced the T-dependent humoral immune response had no effect on activation of specific CD4(+) T cells as measured by cell numbers, cell division, blast transformation, or expression of the activation markers LFA-1 and CD44 in vivo. These observations confirm the importance of complement for the ability of specific IgM to enhance antibody responses and suggest that there is a divergence between the regulation of T- and B-cell responses by IgM.

Complement receptors 1 and 2 in murine antibody responses to IgM-complexed and uncomplexed sheep erythrocytes.

Early complement components are important for normal antibody responses. In this process, complement receptors 1 and 2 (CR1/2), expressed on B cells and follicular dendritic cells (FDCs) in mice, play a central role. Complement-activating IgM administered with the antigen it is specific for, enhances the antibody response to this antigen. Here, bone marrow chimeras between Cr2(-/-) and wildtype mice were used to analyze whether FDCs or B cells must express CR1/2 for antibody responses to sheep erythrocytes (SRBC), either administered alone or together with specific IgM. For robust IgG anti-SRBC responses, CR1/2 must be expressed on FDCs. Occasionally, weak antibody responses were seen when only B cells expressed CR1/2, probably reflecting extrafollicular antibody production enabled by co-crosslinking of CR2/CD19/CD81 and the BCR. When SRBC alone was administered to mice with CR1/2(+) FDCs, B cells from wildtype and Cr2(-/-) mice produced equal amounts of antibodies. Most likely antigen is then deposited on FDCs in a way that optimizes engagement of the B cell receptor, making CR2-facilitated signaling to the B cell superfluous. SRBC bound to IgM will have more C3 fragments, the ligands for CR1/2, on their surface than SRBC administered alone. Specific IgM, forming a complex with SRBC, enhances antibody responses in two ways when FDCs express CR1/2. One is dependent on CR1/2(+) B cells and probably acts via increased transport of IgM-SRBC-complement complexes bound to CR1/2 on marginal zone B cells. The other is independent on CR1/2(+) B cells and the likely mechanism is that IgM-SRBC-complement complexes bind better to FDCs than SRBC administered alone. These observations suggest that the immune system uses three different CR1/2-mediated effector functions to generate optimal antibody responses: capture by FDCs (playing a dominant role), transport by marginal zone B cells and enhanced B cell signaling.

Requirement for complement in antibody responses is not explained by the classic pathway activator IgM.

Animals lacking complement factors C1q, C2, C3, or C4 have severely impaired Ab responses, suggesting a major role for the classic pathway. The classic pathway is primarily initiated by antigen-Ab complexes. Therefore, its role for primary Ab responses seems paradoxical because only low amounts of specific Abs are present in naive animals. A possible explanation could be that the classic pathway is initiated by IgM from naive mice, binding with sufficient avidity to the antigen. To test this hypothesis, a knock-in mouse strain, Cµ13, with a point mutation in the gene encoding the third constant domain of the µ-heavy chain was constructed. These mice produce IgM in which proline in position 436 is substituted with serine, a mutation previously shown to abrogate the ability of mouse IgM to activate complement. Unexpectedly, the Ab response to sheep erythrocytes and keyhole limpet hemocyanin in Cµ13 mice was similar to that in WT mice. Thus, although secreted IgM and the classic pathway activation are both required for the normal primary Ab response, this does not require that IgM activate C. This led us to test Ab responses in animals lacking one of three other endogenous activators of the classic pathway: specific intracellular adhesion molecule-grabbing nonintegrin R1, serum amyloid P component, and C-reactive protein. Ab responses were also normal in these animals.

The first documented case of Aspergillus cardiac surgical site infection in Sweden: an epidemiology study using arbitrarily primed PCR.

Here we report two rare cases of severe thoracic Aspergillus fumigatus infections after lung and heart surgery at the same thoracic intensive care unit at the same time. The main objective was to identify a possible source of transmission. With arbitrarily primed polymerase chain reaction a patient-to-patient transmission could rapidly be ruled out as the cause of the first documented case of aspergillosis after open-heart surgery in Sweden. Although no definitive source was identified, a genetically similar strain was found in a contaminated supply room.

A nine-transmembrane domain topology for presenilin 1.

Presenilin (PS) provides the catalytic core of the gamma-secretase complex. Gamma-secretase activity leads to generation of the amyloid beta-peptide, a key event implicated in the pathogenesis of Alzheimer disease. PS has ten hydrophobic regions, which can all theoretically form membrane-spanning domains. Various topology models have been proposed, and the prevalent view holds that PS has an eight-transmembrane (TM) domain organization; however, the precise topology has not been unequivocally determined. Previous topological studies are based on non-functional truncated variants of PS proteins fused to reporter domains, or immunocytochemical staining. In this study, we used a more subtle N-linked glycosylation scanning approach, which allowed us to assess the topology of functional PS1 molecules. Glycosylation acceptor sequences were introduced into full-length human PS1, and the results showed that the first hydrophilic loop is oriented toward the lumen of the endoplasmic reticulum, whereas the N terminus and large hydrophilic loop are in the cytosol. Although this is in accordance with most current models, our data unexpectedly revealed that the C terminus localized to the luminal side of the endoplasmic reticulum. Additional studies on the glycosylation pattern after TM domain deletions, combined with computer-based TM protein topology predictions and biotinylation assays of different PS1 mutants, led us to conclude that PS1 has nine TM domains and that the C terminus locates to the lumen/extracellular space.

The extreme C terminus of presenilin 1 is essential for gamma-secretase complex assembly and activity.

The gamma-secretase complex catalyzes the cleavage of the amyloid precursor protein in its transmembrane domain resulting in the formation of the amyloid beta-peptide and the cytoplasmic APP intracellular domain. The active gamma-secretase complex is composed of at least four subunits: presenilin (PS), nicastrin, Aph-1, and Pen-2, where the presence of all components is critically required for gamma-cleavage to occur. The PS proteins are themselves subjected to endoproteolytic cleavage resulting in the generation of an N-terminal and a C-terminal fragment that remain stably associated as a heterodimer. Here we investigated the effects of modifications on the C terminus of PS1 on PS1 endoproteolysis, gamma-secretase complex assembly, and activity in cells devoid of endogenous PS. We report that certain mutations and, in particular, deletions of the PS1 C terminus decrease gamma-secretase activity, PS1 endoproteolysis, and gamma-secretase complex formation. We demonstrate that the N- and C-terminal PS1 fragments can associate with each other in mutants having C-terminal truncations that cause loss of interaction with nicastrin and Aph-1. In addition, we show that the C-terminal fragment of PS1 alone can mediate interaction with nicastrin and Aph-1 in PS null cells expressing only the C-terminal fragment of PS1. Taken together, these data suggest that the PS1 N- and C-terminal fragment intermolecular interactions are independent of an association with nicastrin and Aph-1, and that nicastrin and Aph-1 interact with the C-terminal part of PS1 in the absence of an association with full-length PS1 or the N-terminal fragment.

Co-expressed presenilin 1 NTF and CTF form functional gamma-secretase complexes in cells devoid of full-length protein.

The enzyme gamma-secretase catalyzes the intramembrane proteolytic cleavage that generates the amyloid beta-peptide from the beta-amyloid precursor protein. The presenilin (PS) protein is one of the four integral membrane protein components of the mature gamma-secretase complex. The PS protein is itself subjected to endoproteolytic processing, generating stable N- and C-terminal fragment (NTF and CTF, respectively) heterodimers. Here we demonstrate that coexpression of PS1 NTF and CTF functionally mimics expression of the full-length PS1 protein and restores gamma-secretase activity in PS-deficient mammalian cells. The coexpressed fragments re-associate with each other inside the cell, where they also interact with nicastrin, another gamma-secretase complex component. Analysis of gamma-secretase activity following the expression of mutant forms of NTF and CTF, under conditions bypassing endoproteolysis, indicated that the putatively catalytic Asp257 and Asp385 residues have a direct effect on gamma-secretase activity. Moreover, we demonstrate that expression of the wild-type CTF rescues endoproteolytic cleavage of C-terminally truncated PS1 molecules that are otherwise uncleaved and inactive. Recovery of cleavage is critically dependent on the integrity of Asp385. Taken together, our findings indicate that ectopically expressed NTF and CTF restore functional gamma-secretase complexes and that the presence of full-length PS1 is not a requirement for proper complex assembly.

Pen-2 is sequestered in the endoplasmic reticulum and subjected to ubiquitylation and proteasome-mediated degradation in the absence of presenilin.

The gamma-secretase complex catalyzes intramembrane proteolysis of a number of transmembrane proteins, including amyloid precursor protein, Notch, ErbB4, and E-cadherin. gamma-Secretase is known to contain four major protein constituents: presenilin (PS), nicastrin, Aph-1, and Pen-2, all of which are integral membrane proteins. There is increasing evidence that the formation of the complex and the stability of the individual components are tightly controlled in the cell, assuring correct composition of functional complexes. In this report, we investigate the topology, localization, and mechanism for destabilization of Pen-2 in relation to PS function. We show that PS1 regulates the subcellular localization of Pen-2: in the absence of PS, Pen-2 is sequestered in the endoplasmic reticulum (ER) and not transported to post-ER compartments, where the mature gamma-secretase complexes reside. PS deficiency also leads to destabilization of Pen-2, which is alleviated by proteasome inhibitors. In keeping with this, we show that Pen-2, which adopts a hairpin structure with the N and C termini facing the luminal space, is ubiquitylated prior to degradation and presumably retrotranslocated from the ER to the cytoplasm. Collectively, our data suggest that failure to become incorporated into the gamma-secretase complex leads to degradation of Pen-2 through the ER-associated degradation-proteasome pathway.

APP intracellular domain formation and unaltered signaling in the presence of familial Alzheimer's disease mutations.

One of the cardinal neuropathological findings in brains from Alzheimer's disease (AD) patients is the occurrence of amyloid beta-peptide (Abeta) deposits. The gamma-secretase-mediated intramembrane proteolysis event generating Abeta also results in the release of the APP intracellular domain (AICD), which may mediate nuclear signaling. It was recently shown that AICD starts at a position distal to the site predicted from gamma-secretase cleavage within the membrane. This novel site, the epsilon site, is located close to the inner leaflet of the membrane bilayer. The relationship between proteolysis at the gamma and epsilon sites has not been fully characterized. Here we studied AICD signaling in intact cells using a chimeric C99 molecule and a luciferase reporter system. We show that the release of AICD from the membrane takes place in a compartment downstream of the endoplasmic reticulum, is dependent on presenilin proteins, and can be inhibited by treatment with established gamma-secretase inhibitors. Moreover, we find that AICD signaling remains unaltered from C99 derivatives containing mutations associated with increased Abeta42 production and familial AD. These findings indicate that there are very similar routes for Abeta and AICD formation but that FAD-linked mutations in APP primarily affect gamma-secretase-mediated Abeta42 formation, and not AICD signaling.

Partial purification and characterization of gamma-secretase from post-mortem human brain.

One characteristic feature of Alzheimer's disease is the deposition of amyloid beta-peptide (Abeta) as amyloid plaques within specific regions of the human brain. Abeta is derived from the amyloid beta-peptide precursor protein (beta-APP) by the intramembranous cleavage activity of gamma-secretase. Studies in cells have revealed that gamma-secretase is a large multimeric membrane-bound protein complex that is functionally dependent on several proteins, including presenilin, nicastrin, Aph-1, and Pen-2. However, the precise biochemical and molecular nature of gamma-secretase is as yet to be fully elucidated, and no investigations have analyzed gamma-secretase in human brain. To address this we have developed a novel in vitro gamma-secretase activity assay using detergent-solubilized cell membranes and a beta-APP-derived fluorescent probe. We report that human brain-derived gamma-secretase activity co-purifies with a high molecular weight protein complex comprising presenilin, nicastrin, Aph-1, and Pen-2. The inhibitor profile and solubility characteristics of brain-derived gamma-secretase are similar to those described in cells, and proteolysis occurs at the Abeta40- and Abeta42-generating cleavage sites. The ability to isolate gamma-secretase from post-mortem human brain may facilitate the identification of brain-specific modulators of beta-APP processing and provide new insights into the biology of this important factor in the pathogenesis of Alzheimer's disease.

A sensitive and quantitative assay for measuring cleavage of presenilin substrates.

The presenilin (PS) proteins are components of the gamma-secretase activity, which is central in the pathogenesis of Alzheimer's disease. Here we present a novel cell-based reporter gene assay for the quantification of PS-controlled gamma-secretase cleavage of the Alzheimer amyloid precursor protein (APP). We show that this assay offers several advantages, including increased sensitivity and specificity, improved quantification of cleavage, and simultaneous detection of all gamma-secretase cleavages in APP. Furthermore, the APP assay can be used in parallel with a similar assay that records gamma-secretase cleavage of a Notch receptor. The use of these assays to analyze the effects of two known gamma-secretase inhibitors and postulated PS active site mutants on APP and Notch processing demonstrated that inhibitors and mutants that differently affect Notch and APP cleavage can be identified rapidly. The possibility in using these assays for high throughput screening of candidate gamma-secretase inhibitors for APP and Notch in parallel opens up new vistas to systematically search for novel inhibitors that selectively block APP cleavage while not affecting Notch signaling.