👤 Paige Vandenberg

A priority in aging and dementia research is to integrate sex (biological attribute) and gender (sociocultural/behavioural characteristics) in theories, designs, analyses, and intervention protocols. We recently reported a data-mining procedure for operationalizing empirically-derived composite gender variables in archival databases. The present study extends the prior cross-sectional approach by examining sex and gender as separate and interactive predictors of longitudinal data-driven memory trajectory classes. Participants (N = 746) contributed baseline data for binary sex (female/male), education (years), and empirically-derived composite variables representing complementary gender facets. These facets included Manual Tasks and Physical Activities; Social and Household Management; Leisure, Socializing, and Travel; Cognitive Activity and Brain Games; Health Perceptions and Practices; and Subjective Memory Beliefs. We integrated these into a longitudinal episodic memory trajectory distribution spanning 42 years (53-95) of aging. Data-driven latent class growth analysis (LCGA) on the trajectory distribution identified discriminable classes. Using the R3STEP approach, we separately tested sex, gender facets, and education as predictors of membership in the higher (healthier) trajectory classes relative to the lowest (benchmark) class. We then included interaction terms to test for sex moderation of gender effects. Finally, we identified all genotyped participants and tested whether sex and gender effects were moderated by Apolipoprotein E (APOE). LCGA revealed three memory classes: High-Stable (highest level/relatively stable), Moderate/Normal-Declining (average level/moderate decline), and Low-Declining (lowest level/steepest decline). Several variables separately predicted High-Stable membership. For sex, females were more likely than males to belong to this class. For gender, (a) higher scores for Social and Household Management, Cognitive Activity and Brain Games, and Subjective Memory Beliefs predicted High-Stable membership; and (b) higher scores for Manual Tasks and Physical Activities and Health Perceptions and Practices decreased the likelihood of High-Stable membership (relative to Low-Declining). Moderate/Normal-Declining membership was predicted by Social and Household Management (higher). For education, more years predicted High-Stable membership. Moderation analyses indicated that gender effects were consistent across both sexes and APOE carrier status. Data-driven analyses show that biological sex and measurable facets of gender differentially contribute to memory trajectory patterns over a 42-year span of cognitively unimpaired aging. Show less

Inward rectifier potassium (Kir) channels play important roles in the maintenance and control of cell excitability. Both intracellular trafficking and modulation of Kir channel activity are regulated by protein-protein interactions. We adopted a proteomics approach to identify proteins associated with Kir2 channels via the channel C-terminal PDZ binding motif. Detergent-solubilized rat brain and heart extracts were subjected to affinity chromatography using a Kir2.2 C-terminal matrix to purify channel-interacting proteins. Proteins were identified with multidimensional high pressure liquid chromatography coupled with electrospray ionization tandem mass spectrometry, N-terminal microsequencing, and immunoblotting with specific antibodies. We identified eight members of the MAGUK family of proteins (SAP97, PSD-95, Chapsyn-110, SAP102, CASK, Dlg2, Dlg3, and Pals2), two isoforms of Veli (Veli-1 and Veli-3), Mint1, and actin-binding LIM protein (abLIM) as Kir2.2-associated brain proteins. From heart extract purifications, SAP97, CASK, Veli-3, and Mint1 also were found to associate with Kir2 channels. Furthermore, we demonstrate for the first time that components of the dystrophin-associated protein complex, including alpha1-, beta1-, and beta2-syntrophin, dystrophin, and dystrobrevin, interact with Kir2 channels, as demonstrated by immunoaffinity purification and affinity chromatography from skeletal and cardiac muscle and brain. Affinity pull-down experiments revealed that Kir2.1, Kir2.2, Kir2.3, and Kir4.1 all bind to scaffolding proteins but with different affinities for the dystrophin-associated protein complex and SAP97, CASK, and Veli. Immunofluorescent localization studies demonstrated that Kir2.2 co-localizes with syntrophin, dystrophin, and dystrobrevin at skeletal muscle neuromuscular junctions. These results suggest that Kir2 channels associate with protein complexes that may be important to target and traffic channels to specific subcellular locations, as well as anchor and stabilize channels in the plasma membrane. Show less

Walleye (Stizostedion vitreum) is a species of interest for the diversification of North American aquaculture production, and semen cryopreservation is of particular value to this effort. To test the hypothesis that adjusting semen extender composition and dilution ratio increases sperm quality after thawing, three extenders (Ext1, Ext2, Ext3; all with DMSO as a cryoprotectant) and three dilution ratios (semen/extender: 1:5, 1:9, 1:15) were screened. The best results were obtained when semen was diluted at a 1:15 ratio with Ext 1, Rathbun extender supplemented with 7% DMSO, 4 mg/ml BSA and 7.5 mg/ml ProFam, a soy-based protein (P = 0.05, n = 6). This method resulted in 46 +/- 3% motility of the thawed spermatozoa and a mortality rate of 39 +/- 4% whereas Ext2 and Ext3 resulted in motility rates of only 10 and 5%. respectively. To test an additional hypothesis that phosphodiesterase inhibition improves sperm function, we assessed the fertility of sperm frozen in optimal conditions and thawed in the presence or absence of 5 mM theophylline (n = 5). The best result was achieved in water without theophylline, with fertilization rates ranging from 28.51 +/- 6.84 to 59.02 +/- 1.06% eyed-up stage, and theophylline reduced fertility (P < 0.05). Our data show that Ext1 at a dilution ratio of one part semen to 15 parts extender should be used for walleye semen cryopreservation and that the fertilizing media does not benefit from theophylline supplementation. Show less