Medical financial hardship between young adult cancer survivors and matched individuals without cancer in the United States.

BACKGROUND: Young adult cancer survivors face medical financial hardships that may lead to delaying or forgoing medical care. This study describes the medical financial difficulties young adult cancer survivors in the United States experience in the post-Patient Protection and Affordable Care Act period. METHOD: We identified 1009 cancer survivors aged 18 to 39 years from the National Health Interview Survey (2015-2022) and matched 963 (95%) cancer survivors to 2733 control individuals using nearest-neighbor matching. We used conditional logistic regression to examine the association between cancer history and medical financial hardship and to assess whether this association varied by age, sex, race and ethnicity, and region of residence. RESULTS: Compared with those who did not have a history of cancer, young adult cancer survivors were more likely to report material financial hardship (22.8% vs 15.2%; odds ratio = 1.65, 95% confidence interval = 1.50 to 1.81) and behavior-related financial hardship (34.3% vs 24.4%; odds ratio = 1.62, 95% confidence interval = 1.49 to 1.76) but not psychological financial hardship (52.6% vs 50.9%; odds ratio = 1.07, 95% confidence interval = 0.99 to 1.16). Young adult cancer survivors who were Hispanic or lived in the Midwest and South were more likely to report psychological financial hardship than their counterparts. CONCLUSIONS: We found that young adult cancer survivors were more likely to experience material and behavior-related financial hardship than young adults without a history of cancer. We also identified specific subgroups of young adult cancer survivors that may benefit from targeted policies and interventions to alleviate medical financial hardship.

A meta-analysis of brain morphometric aberrations in adolescents who experienced childhood trauma.

Introduction: Childhood trauma is known to have dramatic effects on the risks for developing psychiatric disorders and increased suicidality. We conducted a meta-analysis of whole brain voxel-based morphometry (VBM) correlates of childhood trauma in adolescents exposed to childhood maltreatment (N = 379) and unexposed controls (N = 348). Methods: Anisotropic effect size-signed differential mapping (AES-SDM) was utilized to synthesize the studies. Results: We observed increased volume amongst adolescents with a history of childhood trauma in regions that are involved in motor functions and language production: left precentral gyrus, including part of the left inferior frontal gyrus, left fibers of the body of corpus callosum, and left postcentral gyrus. We observed decreased volume amongst adolescents with a history of childhood trauma in regions that are involved in language processing and/or sensory processing: bilateral cerebellum, bilateral middle temporal gyrus, left rostrum of corpus callosum, and bilateral supramarginal gyrus. Discussion: We suggest that these morphometric differences may be reflective of impaired motor development and increased sensory sensitivity and hypervigilance in adolescents with experiences of childhood trauma. Our results differ from meta-analytical findings in adults with history of childhood trauma and may contribute to a better understanding of neural mechanisms of childhood trauma, prediction of neurodevelopmental outcomes, and development of more effective and personalized therapies.

The uncinate fasciculus in individuals with and at risk for bipolar disorder: A meta-analysis.

BACKGROUND: Bipolar disorder (BD) is a severe mental disorder, characterized by prominent mood swings and emotion regulation (ER) deficits. The uncinate fasciculus (UF), a white matter tract connecting the amygdala and the ventral prefrontal cortex, has been implicated in ER. Aberrancies in UF microstructure may be an endophenotype associated with increased risk for BD. However, studies in individuals with BD and their first-degree relatives (REL) have yielded inconsistent findings. This meta-analysis takes a region-of-interest approach to consolidate the available evidence and elucidate the role of the UF in the risk-architecture of BD. METHODS: Using web-based search engines, we identified diffusion tensor imaging (DTI) studies focusing on the left and right UF and conducted meta-analyses comparing fractional anisotropy (FA) and radial diffusivity (RD) between BD or REL and healthy control participants (HC). RESULTS: We included 32 studies (nBD=1186, nREL=289, nHC=2315). Compared to HC, individuals with BD showed lower FA in the right (WMD=-0.31, p<0.0001) and left UF (WMD=-0.21, p = 0.010), and higher RD in the right UF (WMD=0.32, p = 0.009). We found no significant differences between REL and HC. In the right but not left UF, REL showed higher FA than BD (p = 0.043). CONCLUSION: Our findings support aberrant UF microstructure, potentially related to alterations in myelination, as a mechanism, but not as an endophenotype of BD. However, given the limited power in the REL subsample, the latter finding must be considered preliminary. Studies examining the role of the UF in individuals at familial risk for BD are warranted.

Preventing Irritability and Temper Outbursts in Youth by Building Resilience.

Severe irritability and temper outbursts are risk factors for the onset of serious and lifelong mood disorders. In treating children and adolescents with severe irritability, clinicians should evaluate and address safety issues before acute stabilization of symptoms. Then, clinicians can initiate interventions to prevent the onset or relapses of the undesired behavior and its functional consequences. This review summarizes primary, secondary, and tertiary relapse prevention strategies, with an emphasis on strategies that build resilience in youth that mitigate the onset, recurrence, and progression of emotion dysregulation.

White Matter Microstructure in Individuals With and At Risk for Bipolar Disorder: Evidence for an Endophenotype From a Voxel-Based Meta-analysis.

BACKGROUND: Aberrant white matter (WM) microstructure has been proposed as a mechanism underlying bipolar disorder (BD). Given the strong genetic underpinnings of both WM microstructure and BD, such WM aberrations may be not only a disease marker, but also an endophenotype of BD. If so, they should be observable in individuals at risk for BD (AR) (i.e., first-degree relatives). This meta-analysis integrates evidence on perturbed WM microstructure in individuals with or at risk for BD. METHODS: A comprehensive search of literature published through April 2020 identified diffusion tensor imaging studies that used a voxel-based approach to compare fractional anisotropy (FA) and radial diffusivity between individuals with BD and/or AR individuals and healthy volunteers. Effect size comparison and conjunction analysis allowed identification of endophenotypes and disease markers of BD. Effects of age, sex, mood state, and psychotropic medication were explored using meta-regressions. RESULTS: We included 57 studies in individuals with BD (N = 4631) and 10 in AR individuals (N = 753). Both individuals with and at risk for BD were associated with lower FA in the body and splenium of the corpus callosum. In the BD group, decreased FA and increased radial diffusivity comprised the entire corpus callosum, anterior thalamic radiation, fronto-orbito-polar tracts, and superior longitudinal fasciculus, and were influenced by age, sex, and mood state. Studies with higher proportions of individuals taking lithium or antipsychotics reported smaller FA reductions in BD. CONCLUSIONS: Findings suggest that abnormalities in the body and splenium of the corpus callosum may be an endophenotype for BD, and they associate BD with WM tracts relevant for working memory performance, attention, and reward processing.

Human Skin, Oral, and Gut Microbiomes Predict Chronological Age.

Human gut microbiomes are known to change with age, yet the relative value of human microbiomes across the body as predictors of age, and prediction robustness across populations is unknown. In this study, we tested the ability of the oral, gut, and skin (hand and forehead) microbiomes to predict age in adults using random forest regression on data combined from multiple publicly available studies, evaluating the models in each cohort individually. Intriguingly, the skin microbiome provides the best prediction of age (mean ± standard deviation, 3.8 ± 0.45 years, versus 4.5 ± 0.14 years for the oral microbiome and 11.5 ± 0.12 years for the gut microbiome). This also agrees with forensic studies showing that the skin microbiome predicts postmortem interval better than microbiomes from other body sites. Age prediction models constructed from the hand microbiome generalized to the forehead and vice versa, across cohorts, and results from the gut microbiome generalized across multiple cohorts (United States, United Kingdom, and China). Interestingly, taxa enriched in young individuals (18 to 30 years) tend to be more abundant and more prevalent than taxa enriched in elderly individuals (>60 yrs), suggesting a model in which physiological aging occurs concomitantly with the loss of key taxa over a lifetime, enabling potential microbiome-targeted therapeutic strategies to prevent aging.IMPORTANCE Considerable evidence suggests that the gut microbiome changes with age or even accelerates aging in adults. Whether the age-related changes in the gut microbiome are more or less prominent than those for other body sites and whether predictions can be made about a person's age from a microbiome sample remain unknown. We therefore combined several large studies from different countries to determine which body site's microbiome could most accurately predict age. We found that the skin was the best, on average yielding predictions within 4 years of chronological age. This study sets the stage for future research on the role of the microbiome in accelerating or decelerating the aging process and in the susceptibility for age-related diseases.

Heme bioavailability and signaling in response to stress in yeast cells.

Protoheme (hereafter referred to as heme) is an essential cellular cofactor and signaling molecule that is also potentially cytotoxic. To mitigate heme toxicity, heme synthesis and degradation are tightly coupled to heme utilization in order to limit the intracellular concentration of "free" heme. Such a model, however, would suggest that a readily accessible steady-state, bioavailable labile heme (LH) pool is not required for supporting heme-dependent processes. Using the yeast Saccharomyces cerevisiae as a model and fluorescent heme sensors, site-specific heme chelators, and molecular genetic approaches, we found here that 1) yeast cells preferentially use LH in heme-depleted conditions; 2) sequestration of cytosolic LH suppresses heme signaling; and 3) lead (Pb2+) stress contributes to a decrease in total heme, but an increase in LH, which correlates with increased heme signaling. We also observed that the proteasome is involved in the regulation of the LH pool and that loss of proteasomal activity sensitizes cells to Pb2+ effects on heme homeostasis. Overall, these findings suggest an important role for LH in supporting heme-dependent functions in yeast physiology.

A model for regulation by SynGAP-α1 of binding of synaptic proteins to PDZ-domain 'Slots' in the postsynaptic density.

SynGAP is a Ras/Rap GTPase-activating protein (GAP) that is a major constituent of postsynaptic densities (PSDs) from mammalian forebrain. Its α1 isoform binds to all three PDZ (PSD-95, Discs-large, ZO-1) domains of PSD-95, the principal PSD scaffold, and can occupy as many as 15% of these PDZ domains. We present evidence that synGAP-α1 regulates the composition of the PSD by restricting binding to the PDZ domains of PSD-95. We show that phosphorylation by Ca2+/calmodulin-dependent protein kinase II (CaMKII) and Polo-like kinase-2 (PLK2) decreases its affinity for the PDZ domains by several fold, which would free PDZ domains for occupancy by other proteins. Finally, we show that three critical postsynaptic signaling proteins that bind to the PDZ domains of PSD-95 are present in higher concentration in PSDs isolated from mice with a heterozygous deletion of synGAP.

Connexin gap junction channels and chronic rhinosinusitis.

BACKGROUND: Gap junction channels are formed by connexin (Cx) proteins. These channels facilitate communication between adjacent cells, and some have been implicated in acute and chronic inflammation. We investigated whether altered connexin expression could be associated with the inflammatory changes of the sinonasal mucosa that characterize chronic rhinosinusitis (CRS). Our aims were first to screen normal sinus mucosa to determine the expression profile of the connexin family of genes, and second to compare the level of expression of 3 key connexins (Cx26, Cx30, and Cx43) in CRS and normal sinus mucosa. These 3 connexins have been implicated in lower airway epithelial cell repair, as well as chronic and acute cutaneous wounds. METHODS: Sinus mucosa biopsies were taken from 11 patients with CRS undergoing sinus surgery and from 7 controls with normal sinuses undergoing transnasal pituitary surgery. Gene expression study of the connexin family was performed using polymerase chain reaction (PCR). Subsequent targeted quantitative analyses were done using quantitative real-time PCR (qPCR) and fluorescent immunohistochemistry (IHC). RESULTS: A total of 16 different connexin genes were expressed in the normal mucosa including Cx26, Cx30, and Cx43. The qPCR demonstrated increased abundance of Cx26 (p = 0.005), Cx30 (p = 0.07), and Cx43 (p = 0.04) in CRS compared to control mucosa. IHC confirmed significantly higher levels of Cx43 in CRS (p < 0.001). CONCLUSION: The majority of the connexin family is expressed in normal sinus mucosa. Expression of 3 selected connexins was found elevated in CRS mucosa. Connexin gap junction modulation may offer a novel therapeutic target for CRS.

The action of mimetic peptides on connexins protects fibroblasts from the negative effects of ischemia reperfusion.

Connexins have been proposed as a target for therapeutic treatment of a variety of conditions. The main approaches have been by antisense or small peptides specific against connexins. Some of these peptides enhance communication while others interfere with connexin binding partners or bind to the intracellular and extracellular loops of connexins. Here, we explored the mechanism of action of a connexin mimetic peptide by evaluating its effect on gap junction channels, connexin protein levels and hemichannel activity in fibroblast cells under normal conditions and following ischemia reperfusion injury which elevates Cx43 levels, increases hemichannel activity and causes cell death. Our results showed that the effects of the mimetic peptide were concentration-dependent. High concentrations (100-300 µM) significantly reduced Cx43 protein levels and GJIC within 2 h, while these effects did not appear until 6 h when using lower concentrations (10-30 µM). Cell death can be reduced when hemichannel opening and GJIC were minimised.

High-Performance Capacitive Deionization Disinfection of Water with Graphene Oxide-graft-Quaternized Chitosan Nanohybrid Electrode Coating.

Water disinfection materials should ideally be broad-spectrum-active, nonleachable, and noncontaminating to the liquid needing sterilization. Herein, we demonstrate a high-performance capacitive deionization disinfection (CDID) electrode made by coating an activated carbon (AC) electrode with cationic nanohybrids of graphene oxide-graft-quaternized chitosan (GO-QC). Our GO-QC/AC CDID electrode can achieve at least 99.9999% killing (i.e., 6 log reduction) of Escherichia coli in water flowing continuously through the CDID cell. Without the GO-QC coating, the AC electrode alone cannot kill the bacteria and adsorbs a much smaller fraction (<82.8 ± 1.8%) of E. coli from the same biocontaminated water. Our CDID process consists of alternating cycles of water disinfection followed by electrode regeneration, each a few minutes duration, so that this water disinfection process can be continuous and it only needs a small electrode voltage (2 V). With a typical brackish water biocontamination (with 10(4) CFU mL(-1) bacteria), the GO-QC/AC electrodes can kill 99.99% of the E. coli in water for 5 h. The disinfecting GO-QC is securely attached on the AC electrode surface, so that it is noncontaminating to water, unlike many other chemicals used today. The GO-QC nanohybrids have excellent intrinsic antimicrobial properties in suspension form. Further, the GO component contributes toward the needed surface conductivity of the CDID electrode. This CDID process offers an economical method toward ultrafast, contaminant-free, and continuous killing of bacteria in biocontaminated water. The proposed strategy introduces a green in situ disinfectant approach for water purification.

Stimuli-responsive liposomes for the delivery of nucleic acid therapeutics.

Nucleic acid therapeutics (NATs) are valuable tools in the modulation of gene expression in a highly specific manner. So far, NATs have been actively pursued in both pre-clinical and clinical studies to treat diseases such as cancer, infectious and inflammatory diseases. However, the clinical application of NATs remains a considerable challenge owing to their limited cellular uptake, low biological stability, off-target effect, and unfavorable pharmacokinetics. One concept to address these issues is to deliver NATs within stimuli-responsive liposomes, which release their contents of NATs upon encountering environmental changes such as temperature, pH, and ion strength. In this case, before reaching the targeted tissue/organ, NATs are protected from degradation by enzymes and immune system. Once at the area of interest, localized and targeted delivery can be achieved with minimal influence to other parts of the body. Here, we discuss the latest developments and existing challenges in this field. FROM THE CLINICAL EDITOR: Nucleic acid therapeutics have been shown to enhance or eliminate specific gene expression in experimental research. Unfortunately, clinical applications have so far not been realized due to problems of easy degradation and possible toxicity. The use of nanosized carriers such as liposomes to deliver nucleic acids is one solution to overcome these problems. In this review article the authors describe and discuss the potentials of various trigger-responsive "smart" liposomes, with a view to help other researchers to design better liposomal nucleic acid delivery systems.

Targeting Cx43 and N-cadherin, which are abnormally upregulated in venous leg ulcers, influences migration, adhesion and activation of Rho GTPases.

BACKGROUND: Venous leg ulcers can be very hard to heal and represent a significant medical need with no effective therapeutic treatment currently available. PRINCIPAL FINDINGS: In wound edge biopsies from human venous leg ulcers we found a striking upregulation of dermal N-cadherin, Zonula Occludens-1 and the gap junction protein Connexin43 (Cx43) compared to intact skin, and in stark contrast to the down-regulation of Cx43 expression seen in acute, healing wounds. We targeted the expression of these proteins in 3T3 fibroblasts to evaluate their role in venous leg ulcers healing. Knockdown of Cx43 and N-cadherin, but not Zonula Occludens-1, accelerated cell migration in a scratch wound-healing assay. Reducing Cx43 increased Golgi reorientation, whilst decreasing cell adhesion and proliferation. Furthermore, Connexin43 and N-cadherin knockdown led to profound effects on fibroblast cytoskeletal dynamics after scratch-wounding. The cells exhibited longer lamelipodial protrusions lacking the F-actin belt seen at the leading edge in wounded control cells. This phenotype was accompanied by augmented activation of Rac-1 and RhoA GTPases, as revealed by Förster Resonance Energy Transfer and pull down experiments. CONCLUSIONS: Cx43 and N-cadherin are potential therapeutic targets in the promotion of healing of venous leg ulcers, by acting at least in part through distinct contributions of cell adhesion, migration, proliferation and cytoskeletal dynamics.

Alterations of glutamate, glutamine, and related amino acids in the anterior eye secondary to ischaemia and reperfusion.

PURPOSE: To assess the amino acid levels of the ciliary epithelium, aqueous and lens under normal conditions and secondary to ischaemia and reperfusion. METHODS: We assessed the amino acids glutamate, glutamine, aspartate, alanine, gamma-amino butyric acid, glycine, arginine and taurine in albino Sprague-Dawley rats. Acute ischaemia was created in the eye and the different anterior eye components were assessed for amino acid levels. Quantitative immunocytochemistry was used to compare amino acid profiles within the ciliary processes immediately after ischaemia and after 4 days of reperfusion. Liquid chromatography was used to determine amino acid levels in the aqueous humour and quantitative immunocytochemistry to determine the location and alterations of amino acids in the lens 4 days after ischaemia/reperfusion. RESULTS: Elevated amino acid levels were evident in the ciliary epithelium immediately after ischaemia. After 4 days of reperfusion, decreased levels of glutamine, gamma-aminobutyric acid, glycine and arginine were evident in the ciliary epithelium, in particular the nonpigmented epithelial cells. The amino acid levels in the aqueous humour remained unchanged after ischaemia/reperfusion and thus showed considerable resilience to this kind of injury. However, significant reductions of glutamate, glutamine, alanine, glycine, arginine and taurine were observed in the lens 4 days after ischaemia/reperfusion. CONCLUSIONS: We propose a model to explain the maintenance of amino acid homeostasis in the aqueous humour despite altered levels in both the ciliary processes and lens.

Cellular localization of glutamate and glutamine metabolism and transport pathways in the rat ciliary epithelium.

PURPOSE: To investigate how glutamate and glutamine levels are established in the aqueous humor by identifying the transporters and metabolism pathways that contribute to the differential accumulation of glutamate and glutamine between the distinct epithelial cell layers that constitute the ciliary body. METHODS: Postembedding immunohistochemistry and silver intensification were used to quantify the relative distributions of glutamate, glutamine, and related amino acids (aspartate, alanine, GABA, and glycine) in the pigmented (PE) and nonpigmented (NPE) epithelial cells of the ciliary body. Fluorescent immunocytochemistry was used to localize Na(+)-dependent glutamate transporters (EAAT1-5), glutamine transporters (LAT1, LAT2, and b(0,+)AT), and the enzyme glutamine synthetase (GS) in the ciliary epithelium. Intravitreal injection of the GS inhibitor methionine sulfoximine (MSO) or the EAAT functional probe D-aspartate was used to modulate GS activity and indirectly monitor glutamate uptake from the aqueous, respectively. RESULTS: Although glutamate, glutamine, and alanine were preferentially accumulated in NPE relative to PE cells, no such differential distribution of aspartate, GABA, or glycine was observed. This differential distribution of amino acids was abolished by a single injection of MSO that caused a decrease in glutamine and an increase in glutamate levels in NPE compared with PE cells. This amino acid distribution plus an observed strong labeling of EAAT3 in the interface between the PE and the NPE cell layers indicate that EAAT3 mediates the uptake of glutamate from the blood. Weaker EAAT3 labeling of the basolateral membranes of NPE cells, coupled with the accumulation of injected D-aspartate by the ciliary epithelium, indicates that NPE cells also mediate glutamate uptake directly from the aqueous. In contrast, the basolateral localization of LAT1 and b(0,+)AT in NPE cells suggest that these transporters may mediate glutamine efflux from the NPE cells into the aqueous. CONCLUSIONS: The basolateral membrane localization of EAAT3 and LAT1/b(0,+)AT in NPE cells indicates that the low glutamate and high glutamine levels observed in the aqueous are determined by glutamate uptake and glutamine efflux, respectively. Furthermore, the concentration gradient for glutamine efflux appears to be generated by the active accumulation of glutamate by EAAT3, located in the apical membrane of NPE cells and the subsequent conversion of the accumulated glutamate to glutamine by GS in NPE cells. This suggests that in contrast to fluid transport, which uses both the PE and the NPE cell layers, the transepithelial transport of glutamine occurs primarily in the NPE cell layer.

Glutamate metabolic pathways and retinal function.

Glutamate is a major neurotransmitter in the CNS but is also a key metabolite intimately coupled to amino acid production/degradation. We consider the effect of inhibition of two key glutamate metabolic enzymes: glutamine synthetase (GS) and aspartate aminotransferase on retinal function assessed using the electroretinogram to consider photoreceptoral (a-wave) and post-receptoral (b-wave) amplitudes. Quantitative immunocytochemistry was used to assess amino acid levels within photoreceptors, ganglion and Müller cells secondary to GS inhibition. Intravitreal injections of methionine sulfoximine reduced GS immunoreactivity in the rat retina. Additionally, glutamate and its precursor aspartate was reduced in photoreceptors and ganglion cells, but elevated in Müller cells. This reduction in neuronal glutamate was consistent with a deficit in neurotransmission (-75% b-wave reduction). Exogenous glutamine supply completely restored the b-wave, whereas other amino acid substrates (lactate, pyruvate, alpha-ketoglutarate, and succinate) only partially restored the b-wave (16-20%). Inhibition of the aminotranferases using aminooxyacetic acid had no effect on retinal function. However, aminooxyacetic acid application after methionine sulfoximine further reduced the b-wave (from -75% to -92%). The above data suggest that de novo glutamate synthesis involving aspartate aminotransferase can partially sustain neurotransmission when glutamate recycling is impaired. We also show that altered glutamate homeostasis results in a greater change in amino acid distribution in ganglion cells compared with photoreceptors.

Characterization of the cystine/glutamate transporter in the outer plexiform layer of the vertebrate retina.

The cystine/glutamate transporter (Xc-) is widely expressed in the central nervous system and is thought to play a role in glutamatergic neurotransmission by releasing low levels of glutamate. Although previous studies have localized the transporter throughout the retina, we now present results from localization and functional studies within the first synaptic layer, i.e. the outer plexiform layer. Using light and electron microscopy, we have localized the Xc- transporter to the ribbon complex of both rod and cone photoreceptors in the rat, cow, lamprey, chicken and monkey retina, suggesting that the pre-synaptic expression of the Xc- transporter on the photoreceptor ribbon complex is phylogenetically preserved. The Xc- transporter does not appear to be located within the ribbon synapse of the inner plexiform layer. Developmentally, the evolution of distinct ribbon-shaped Xc- labelling in the outer plexiform layer parallels the known morphological and electrophysiological maturation of photoreceptors. Using the cation channel probe agmatine, we tracked cation fluxes within bipolar cells and therefore indirectly determined the modulation of glutamate release from photoreceptors. Such cystine-driven alteration in agmatine entry into bipolar cells can be modified by a specific metabotropic glutamate receptor 6 antagonist [(RS)-alpha-cyclopropyl-4-phosphonophenylglycine] and an Xc- transport inhibitor [(S)-4-carboxyphenylglycine]. The phylogenetic preservation of the transporter, its ultrastructural localization to the ribbon synapse and functional modulation of post-receptoral neurons collectively support a role for the Xc- transporter in glutamate neurotransmission in the outer retina of vertebrates. We have therefore proposed a model of glutamate release in the photoreceptor synapse that incorporates the Xc- transporter, which complements the established vesicular-mediated glutamate release.

Molecular and functional mapping of regional differences in P2Y receptor expression in the rat lens.

Extracellular ATP has been shown to mobilize intracellular Ca(2+) in cultured ovine lens epithelial cells and in human lens epithelium, suggesting a role for purines in the modulation of lens transparency. In this study, we characterized the expression profiles of P2Y receptor isoforms throughout the rat lens at both the molecular and the functional levels. RT-PCR indicated that P2Y(1), P2Y(2), P2Y(4) and P2Y(6) are expressed in the lens, while P2Y(12), P2Y(13) and P2Y(14) are not. Immunohistochemistry, using isoform specific antibodies, indicated that the epithelium does not express P2Y(1) and P2Y(2), but that the underlying fiber cells, which differentiate from the epithelial cells, exhibit strong membranous labeling. Although co-expressed in fiber cells, differences in P2Y(1) and P2Y(2) expression were apparent. P2Y(1) expression extended deeper into the lens than P2Y(2), and its expression co-localized with Cx50 gap junction plaques, while P2Y(2) did not. Labeling for P2Y(4) and P2Y(6) receptors were observed in both epithelial cells and fiber cells, but the labeling was predominantly cytoplasmic in nature. While purine agonist (ATP, ADP, UTP and UDP) application to the lens induced mobilization of intracellular Ca(2+) in cortical fiber cells, little to no effect was observed in the anterior and equatorial epithelium. Thus the inability of UTP and UDP to mobilize intracellular Ca(2+) in the epithelium and the predominately cytoplasmic location of P2Y(4) and P2Y(6) suggests that these receptors may represent an inactive pool of receptors that may be activated under non-physiological conditions. In contrast, our results indicated that P2Y(1) and P2Y(2) are functionally active in fiber cells and their differential subcellular expression patterns suggest they may regulate distinct processes in the lens under steady state conditions.