Sentinel Surveillance System Implementation and Evaluation for SARS-CoV-2 Genomic Data, Washington, USA, 2020-2021.

Genomic data provides useful information for public health practice, particularly when combined with epidemiologic data. However, sampling bias is a concern because inferences from nonrandom data can be misleading. In March 2021, the Washington State Department of Health, USA, partnered with submitting and sequencing laboratories to establish sentinel surveillance for SARS-CoV-2 genomic data. We analyzed available genomic and epidemiologic data during presentinel and sentinel periods to assess representativeness and timeliness of availability. Genomic data during the presentinel period was largely unrepresentative of all COVID-19 cases. Data available during the sentinel period improved representativeness for age, death from COVID-19, outbreak association, long-term care facility-affiliated status, and geographic coverage; timeliness of data availability and captured viral diversity also improved. Hospitalized cases were underrepresented, indicating a need to increase inpatient sampling. Our analysis emphasizes the need to understand and quantify sampling bias in phylogenetic studies and continue evaluation and improvement of public health surveillance systems.

GenoRisk: A polygenic risk score for Alzheimer's disease.

INTRODUCTION: Recent clinical trials are considering inclusion of more than just apolipoprotein E (APOE) ε4 genotype as a way of reducing variability in analysis of outcomes. METHODS: Case-control data were used to compare the capacity of age, sex, and 58 Alzheimer's disease (AD)-associated single nucleotide polymorphisms (SNPs) to predict AD status using several statistical models. Model performance was assessed with Brier scores and tenfold cross-validation. Genotype and sex × age estimates from the best performing model were combined with age and intercept estimates from the general population to develop a personalized genetic risk score, termed age, and sex-adjusted GenoRisk. RESULTS: The elastic net model that included age, age x sex interaction, allelic APOE terms, and 29 additional SNPs performed the best. This model explained an additional 19% of the heritable risk compared to APOE genotype alone and achieved an area under the curve of 0.747. DISCUSSION: GenoRisk could improve the risk assessment of individuals identified for prevention studies.

Specific domains in anterior pharynx-defective 1 determine its intramembrane interactions with nicastrin and presenilin.

γ-Secretase, a multisubunit transmembrane protease comprised of presenilin, nicastrin, presenilin enhancer 2, and anterior pharynx-defective one, participates in the regulated intramembrane proteolysis of Type I membrane proteins including the amyloid precursor protein (APP). Although Aph-1 is thought to play a structural role in the assembly of γ-secretase complex and several transmembrane domains (TMDs) of Aph-1 have been shown to be critical for its function, the importance of the other domains of Aph-1 remains elusive. We screened a series of Aph-1 mutants and focused on nine mutations distributed in six different TMDs of human APH-1aS, assessing their ability to complement mouse embryonic fibroblasts lacking Aph-1. We showed that mutations in TMD4 (G126) and TMD5 (H171) of Aph-1aS prevented the formation of the Nct/Aph-1 subcomplex. Importantly, although mutations in TMD3 (Q83/E84/R85) and TMD6 (H197) of APH-1aS did not affect Nct/Aph-1 subcomplex formation, both mutations prevented further association/endoproteolysis of PS1. We propose a model that identifies critical TMDs of Aph-1 for associations with Nct and PS for the stepwise assembly of γ-secretase components.

A case of sweet syndrome with spleen and lymph node involvement preceded by parvovirus B19 infection, and a review of the literature on extracutaneous sweet syndrome.

A 45-year-old white woman presented with fever, arthalgias, and widespread erythematous papules after a recent Parvovirus B19 infection. Biopsy findings were consistent with classic Sweet syndrome. A splenectomy, which was performed due to radiographic evidence of multiple splenic lesions, revealed a diffuse neutrophil-predominant infiltrate with formation of numerous "abcesses." Her skin lesions recurred several times over the next 6 years, with repeat biopsies showing evidence of recurrent Sweet neutrophilic dermatosis. The initial and recurrent skin eruptions were responsive to systemic steroids. A paratracheal lymph node biopsy was later performed to evaluate widespread lymphadenopathy, which showed complete effacement of nodal architecture by a mixed inflammatory and fibrotic process including neutrophils, with features reminiscent of cat-scratch disease. Special stains, tissue culture studies, and serologies were negative for an infectious etiology, and an extensive evaluation for hematologic or other malignancy was negative. This clinical-pathologic presentation was consistent with Sweet syndrome involving both cutaneous and lymphoreticular (spleen and lymph nodes) sites. This case illustrates the importance of recognizing extracutaneous involvement in Sweet syndrome and differentiating this from infectious, malignant, and other processes. The literature on extracutaneous involvement of Sweet syndrome is reviewed.

Persistent pruritic papules and plaques: a characteristic histopathologic presentation seen in a subset of patients with adult-onset and juvenile Still's disease.

BACKGROUND: 'Persistent pruritic papules and plaques' of Still's disease represents a recently described eruption seen in a subset of patients. Most cases reported in the literature to date have been associated with adult-onset Still's disease. METHODS: We present the clinical and histopathologic examinations of three female patients ranging in age from 15 to 54 years. RESULTS: Our three patients each presented with clinical findings consistent with Still's disease. The youngest patient suffered from the juvenile form of Still's disease (systemic-onset juvenile rheumatoid arthritis). Each patient had a persistent, pruritic eruption with histopathologic findings of dyskeratosis confined to the upper layers of the epidermis as well as a sparse superficial dermal infiltrate containing scattered neutrophils. CONCLUSIONS: These cases confirm the characteristic clinical and histopathologic findings of 'persistent papules and plaques of Still's disease' and show the potential for this eruption in both the adult and juvenile age groups.

A case of lobular capillary hemangioma (pyogenic granuloma), localized to the subcutaneous tissue, and a review of the literature.

Lobular capillary hemangioma (pyogenic granuloma) is a common vascular proliferation that typically occurs in the superficial dermis, although rarely a subcutaneous form has been reported. Although these lesions are considered benign, localized recurrence after excision and satellite spread of the lesions are known phenomena. A case of lobular capillary hemangioma with the unusual features of both subcutaneous localization and locally aggressive behavior following surgery in a patient with a history of estrogen use and local trauma prior to the onset of the lesion is presented. The literature of lobular capillary hemangioma is reviewed, and the differential diagnosis is discussed.

N-glycosylation of human nicastrin is required for interaction with the lectins from the secretory pathway calnexin and ERGIC-53.

The gamma-secretase complex, composed of four non-covalently bound transmembrane proteins Presenilin, Nicastrin (NCT), APH-1 and PEN-2, is responsible for the intramembranous cleavage of amyloid precursor protein (APP), Notch and several other type I transmembrane proteins. gamma-Secretase cleavage of APP releases the Abeta peptides, which form the amyloid plaques characteristic of Alzheimer's disease brains, and cleavage of Notch releases an intracellular signalling peptide that is critical for numerous developmental processes. NCT, a type I membrane protein, is the only protein within the complex that is glycosylated. The importance of these glycosylation sites is not fully understood. Here, we have observed that NCT N-linked oligosaccharides mediated specific interactions with the secretory pathway lectins calnexin and ERGIC-53. In order to investigate the role played by N-glycosylation, mutation of each site was performed. All hNCT mutants interacted with calnexin and ERGIC-53, indicating that the association was not mediated by any single N-glycosylation site. Moreover, the interaction with ERGIC-53 still occurred in PS1/2 double knockout cells as detected in immunoprecipitation as well as confocal immunofluorescence microscopy studies, which indicated that NCT interacted with ERGIC-53 prior to its association with the active gamma-secretase complex.

Presenilin modulates Pen-2 levels posttranslationally by protecting it from proteasomal degradation.

The gamma-secretase complex functions to cleave several type I transmembrane proteins within their transmembrane domains. These include the amyloid precursor protein, which is central to Alzheimer's disease pathogenesis, as well as N-cadherin and Notch, which regulate transcription. This complex is composed of four requisite integral membrane proteins: presenilin 1 (PS1) or presenilin 2 (PS2), nicastrin, Pen-2, and Aph-1. How these proteins coordinately regulate one another and assemble to form a functional complex is not well understood. In this report we demonstrate that PS1 selectively enhances the stability of Pen-2 protein but not that of nicastrin or Aph-1. In the absence of PS1, Pen-2 was rapidly degraded by the proteasome. As PS1 levels increased, so too did the half-life of Pen-2 and therefore its steady-state levels. In addition, Pen-2 protein levels correlated with PS1 levels not only in cell culture but in transgenic mouse models as well. The genetic absence of PS1 and PS2, and therefore of gamma-secretase-dependent mediation of transcriptional activity, did not affect Pen-2 mRNA levels. Rather, presenilin (PS) regulates Pen-2 levels posttranslationally by preventing its degradation by the proteasome. Thus, the amount of Pen-2 protein is effectively titrated by its PS binding partner, and the rapidity with which Pen-2 is degraded in the absence of PS interactions could provide a mechanism to tightly regulate gamma-secretase complex assembly.

Membrane topology and nicastrin-enhanced endoproteolysis of APH-1, a component of the gamma-secretase complex.

APH-1, presenilin, nicastrin, and Pen-2 are proteins with varying membrane topologies that compose the gamma-secretase complex, which is responsible for the intramembrane proteolysis of several substrates including the amyloid precursor protein. APH-1 is known to be necessary for gamma-secretase activity, but its precise function in the complex is not fully understood, and its membrane topology has not been described, although it is predicted to traverse the membrane seven times. To investigate this, we used selective permeabilization of the plasma membrane and immunofluorescence microscopy to show that the C terminus of the APH-1 resides in the cytosolic space. Insertion of N-linked glycosylation sites into each of the hydrophilic loop domains and the N terminus of APH-1 showed that the N-terminal domain as well as loops 2, 4, and 6 could be glycosylated, whereas loops 1, 3, and 5 were not. Thus, APH-1 topologically resembles a seven-transmembrane domain receptor with the N terminus and even-numbered loops facing the endoplasmic reticulum lumen, and the C terminus and odd-numbered loops reside in the cytosolic space. By using these glycosylation mutants, we provide evidence that the association between nicastrin and APH-1 may occur very soon after APH-1 synthesis and that the interaction between these two proteins may rely more heavily on the transmembrane domains of APH-1 than on the loop domains. Furthermore, we found that APH-1 can be processed by several endoproteolytic events. One of these cleavages is strongly up-regulated by co-expression of nicastrin and generates a stable C-terminal fragment that associates with nicastrin.

Signaling by ephrinB1 and Eph kinases in platelets promotes Rap1 activation, platelet adhesion, and aggregation via effector pathways that do not require phosphorylation of ephrinB1.

We have previously shown that platelets express 2 receptor tyrosine kinases, EphA4 and EphB1, and the Eph kinase ligand, ephrinB1, and proposed that transcellular Eph/ephrin interactions made possible by the onset of platelet aggregation promote the further growth and stability of the hemostatic plug. The present study examines how this might occur. The results show that clustering of either ephrinB1 or EphA4 causes platelets to adhere to immobilized fibrinogen via alpha(IIb)beta(3). Adhesion occurs more slowly than with adenosine diphosphate (ADP) and requires phosphatidylinositol 3 (PI3)-kinase and protein kinase C activity but not ephrinB1 phosphorylation. By itself, Eph and ephrin signaling is insufficient to cause aggregation or the binding of soluble fibrinogen, but it can potentiate aggregation initiated by a Ca(++) ionophore or by agonists for thrombin and thromboxane receptors. It also enhances Rap1 activation without requiring ADP secretion, ephrinB1 phosphorylation, or the activation of PI3-kinase and Src. From this we conclude that (1) Eph/ephrin signaling enhances the ability of platelet agonists to cause aggregation provided that those agonists can increase cytosolic Ca(++); (2) this is accomplished in part by activating Rap1; and (3) these effects require oligomerization of ephrinB1 but not phosphotyrosine-based interactions with the ephrinB1 cytoplasmic domain.