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Integrated molecular and immune profiling identifies FOXA1 as a complementary co-target to MUC1 for bispecific immunotherapy in breast cancer.

In breast cancer immunotherapy, Mucin 1 (MUC1) is a well-established target with promising preclinical results; however, single targeting of MUC1 has demonstrated limited efficacy in clinical trials, largely due to tumor heterogeneity, diverse glycosylation patterns, and an immunosuppressive TME. Identification of complementary co-targets enables bi-specific or dual-target immunotherapy, limiting antigen escape, improving specificity, and reducing relapse. Here, we employed a comprehensive multi-layered analytical approach to evaluate MUC1 expression, clinical relevance, and methylation status, followed by systematic screening of MUC1-correlated genes. Antigenicity prediction and protein-protein interaction analyses identified Forkhead Box A1 (FOXA1) as a potential functional partner. Expression analysis revealed concordant patterns of MUC1 and FOXA1 across breast cancer samples, while network mapping demonstrated shared interactions with adhesion-associated proteins, including CTNNB1, CTNND1, and CDH1, suggesting roles in epithelial organization and tumor progression. Further validation using gene expression datasets from Indian breast cancer cohorts confirmed consistent expression and correlation patterns, supporting reproducibility across populations. Immune profiling revealed an inverse association between MUC1-FOXA1 co-expression and immune-related gene signatures, with high co-expression linked to reduced infiltration of dendritic cells, CD4⁺ and CD8⁺ T cells, macrophages, and natural killer cells, indicative of an immunosuppressive microenvironment. Negative correlations with MHC Class I genes further suggested impaired antigen presentation. Epitope prediction identified high-affinity peptides from both targets with strong MHC Class I binding potential. Collectively, these findings support the associated role of MUC1 and FOXA1 as dual immunotherapeutic targets in breast cancer.

Hepatocyte Nuclear Factor 3-alpha↗

Serial kinematic analysis of the canine hindlimb joints after deafferentation and anterior cruciate ligament transection.

OBJECTIVE AND DESIGN: Transection of the anterior cruciate ligament 2 weeks after ipsilateral hindlimb deafferentation leads to osteoarthritis of the knee joint within 3 weeks. We analyzed the gait of six dogs that underwent this procedure in order to identify kinematic changes that could account for this rapid joint degeneration. All animals were video taped, 1, 3, 6, 9 and 13 weeks after surgery while they trotted on a treadmill. RESULTS: In each dog, extension of the hip, knee and ankle joints of the unstable limb was increased, and the yield phase of the unstable knee was delayed or attenuated. When killed, five of six dogs showed a large full-thickness cartilage ulcer on the distal and/or anterior surface of the medial femoral condyle of the unstable knee; in the sixth dog, a smaller ulcer was observed. However, the severity of pathology in each individual was not obviously related to difference among the dogs in postoperative joint kinematics. CONCLUSIONS: These data, and results of prior studies in humans and dogs, suggest that knee hyperextension resulting from limb deafferentation, and knee instability resulting from anterior cruciate ligament transection, operate in concert to create a mechanical environment (i.e., increased tibiofemoral separation and changes in the loading of articular surfaces) that results in rapid joint breakdown.

Afferent Pathways↗

Interleukin-4 gene expression in activated human T lymphocytes is regulated by the cyclic adenosine monophosphate-dependent signaling pathway.

In the present study, we have investigated the involvement of the cyclic adenosine monophosphate (cAMP)-dependent signaling pathway on interleukin-4 (IL-4) gene expression in freshly isolated human T lymphocytes. 2'-0-dibutyryl cAMP (db-cAMP) and prostaglandin E2 (PGE2) were used to directly and indirectly activate the protein kinase A pathway. Northern analysis showed that concanavalin A (Con A)-, anti-CD3 (alpha CD3)-, or anti-CD3 plus anti-CD28 (alpha CD3/alpha CD28)-induced accumulation of IL-4 mRNA was inhibited by db-cAMP (10(-3) mol/L). Db-cAMP showed a steep dose-dependent inhibition; concentrations < or = 10(-4) mol/L did not affect IL-4 mRNA accumulation. In contrast, GM-CSF mRNA expression showed a wider dose-dependent range; 10(-5) mol/L db-cAMP still affected GM-CSF accumulation. PGE2 inhibited the Con A- and alpha CD3/alpha CD28-induced accumulation of IL-4 mRNA in a dose-dependent fashion. Con A-induced IL-4 mRNA was inhibited by 10(-4) to 10(-7) mol/L PGE2; alpha CD3/alpha CD28-induced IL-4 mRNA was inhibited by 10(-5) to 10(-8) mol/L PGE2. Nuclear run-on experiments showed that the inhibitory effects of db-cAMP and PGE2 were accomplished at transcriptional level in Con A-activated T cells, whereas changes at transcriptional and posttranscriptional level were involved in alpha CD3/alpha CD28-activated T lymphocytes. In contrast to Con A and alpha CD3/alpha CD28 activation, phorbol myristate acetate plus A23187-induced IL-4 mRNA expression was insensitive to the inhibitory effect of db-cAMP and PGE2. Moreover, it appeared that the sensitivity for cAMP-mediated downregulation could not be blocked by stimulation T lymphocytes with alpha CD3/alpha CD28 in the presence of IL-2, IL-7, IL-10, IL-12, or a combination of these cytokines. Finally, it was shown that, in accordance with the mRNA studies, db-cAMP and PGE2 suppressed the IL-4 secretion in Con A- and alpha CD3/alpha CD28-activated T cells. In conclusion, these data show that IL-4 expression is negatively regulated by the protein kinase A-dependent signaling pathway by transcriptional and posttranscriptional mechanisms that depend on costimulatory signals.

Antibodies, Monoclonal↗

Isolated isobutyryl-CoA dehydrogenase deficiency: an unrecognized defect in human valine metabolism.

A 2-year-old female was well until 12 months of age when she was found to be anemic and had dilated cardiomyopathy. Total plasma carnitine was 6 microM and acylcarnitine analysis while receiving carnitine supplement revealed an increase in the four-carbon species. Urine organic acids were normal. In vitro analysis of the mitochondrial pathways for beta oxidation, and leucine, valine, and isoleucine metabolism was performed in fibroblasts using stable isotope-labeled precursors to these pathways followed by acylcarnitine analysis by tandem mass spectrometry. 16-2H3-palmitate was metabolized normally down to the level of butyryl-CoA thus excluding SCAD deficiency. 13C6-leucine and 13C6-isoleucine were also metabolized normally. 13C5-valine incubation revealed a significant increase in 13C4-isobutyrylcarnitine without any incorporation into propionylcarnitine as is observed normally. These same precursors were also evaluated in fibroblasts with proven ETF-QO deficiency in which acyl-CoA dehydrogenase deficiencies in each of these pathways was clearly identified. These results indicate that in the human, there is an isobutyryl-CoA dehydrogenase which exists as a separate enzyme serving only the valine pathway in addition to the 2-methyl branched-chain dehydrogenase which serves both the valine and the isoleucine pathways in both rat and human.

Cardiomyopathies↗

Safely reducing length of stay after open radical retropubic prostatectomy under the guidance of a clinical care pathway.

BACKGROUND: Collaborative care pathways have proven to be a safe and effective method of decreasing length of hospital stay (LOS) and costs after radical retropubic prostatectomy (RRP). In the current study, the authors evaluated the safety and efficacy of a pathway transitioning from a 3-day to a 2-day LOS. METHODS: The authors performed a retrospective chart review of 994 patients who underwent RRP at the study institution between July 1994 and December 2001. A total of 561 patients were managed on a 3-day LOS pathway, 172 were managed during the transition period from 3 to 2 days, and 261 were managed on a 2-day LOS pathway. Statistical analysis was performed comparing preoperative variables and complications among the three groups. RESULTS: No statistically significant differences were found in comparisons of preoperative and demographic variables including age, race, medical comorbidities, preoperative prostate-specific antigen level, clinical stage of disease at presentation, and biopsy Gleason score. Forty-nine of the 561 patients (8.7%) remained longer than their targeted 3-day LOS, whereas 14 of 261 patients (5.4%) were hospitalized for longer than their targeted 2-day LOS, a difference that approached statistical significance (P = 0.058). During the transition period, 99 of 172 patients (57.6%) were discharged on postoperative Day 2 and 73 patients (42.4%) were discharged on postoperative Day 3. Complication rates were found to be significantly lower (P = 0.013) in the 2-day LOS group (2.3%) compared with the 3-day LOS group (7.0%) and the transition group (8.1%). The rate of readmission remained constant at 3% during this time period. CONCLUSIONS: Overall, greater than 90% of patients were discharged within 2-3 days of surgery with acceptable complication rates, suggesting that in a consistent patient population, the transition from a 3-day LOS to a 2-day LOS can be done successfully without compromising patient safety. Evaluation currently is ongoing with regard to a 1-day LOS.

Adult↗

Oscillatory and burst discharge across electrosensory topographic maps.

1. Three parallel maps of the distribution of tuberous electroreceptor inputs are found in the medullary electrosensory lateral line lobe (ELL) of weakly electric fish. Pyramidal cells in each map are known to respond differentially to the frequency of amplitude modulations (AMs) of external electric fields in vivo. We used an in vitro ELL slice preparation of Apteronotus leptorhynchus to compare the characteristics of spontaneously active single units across the three tuberous maps. It was our objective to determine whether spontaneous bursting activity of pyramidal cells in each map correlates with the known AM frequency selectivities of pyramidal cells in vivo. 2. Single-unit discharges were recorded from the pyramidal cell layer of the centromedial segment (CMS), centrolateral segment (CLS), and lateral segment (LS) of the ELL. Stochastic analysis of interspike intervals (ISIs) was used to identify bursting and nonbursting unit activity, and to separately analyze intra- and interburst ISIs. Four ISI patterns were identified as 1) bursting, 2) regular spiking, 3) irregular spiking, and 4) highly irregular spiking. This work focuses primarily on the characteristics of bursting units across the ELL segments. 3. Spontaneous bursting discharge was identified in all three maps (68 of 97 units), with several characteristics changing in a gradual manner across the maps. The coefficient of variation (CV) of ISIs and intraburst ISIs decreased significantly from the CMS to the LS, whereas the CV of burst periods increased significantly from the CMS to the LS. Autocorrelations and power spectral density analysis identified units discharging in an oscillatory manner with the following ratio: CMS, 75%; CLS, 4%; LS, 8%. 4. The mean period of spike bursts decreased significantly across the segments (CMS, 2.7 s; CLS, 1.2 s; LS, 1.1 s) primarily because of a shortening of mean burst duration (CMS, 1.0 s; CLS, 0.1 s; LS, 0.05 s). The average number of spikes per burst decreased significantly across the maps (CMS, 61; CLS, 8; LS, 8), whereas the average frequency of spikes per burst increased (CMS, 90 Hz; CLS, 130 Hz; LS, 178 Hz), mainly through an increase in the maximal frequencies attained by units within each map. 5. Bursts in the CMS were unstructured in that the intraburst ISIs were serially independent, whereas for many units in the CLS and especially the LS there were serial dependencies of successive spikes, with alternating short and long ISIs during the burst. 6. These data reveal that the characteristics of bursting unit activity differ between the CMS, CLS, and LS maps in vitro, implying a modulation of the factors underlying burst discharge across multiple sensory maps. Because the pattern of change in burst activity between these maps parallels that of pyramidal cell AM frequency selectivity in vivo, oscillatory and burst discharge may represent the cellular mechanism used to tune these cells to specific frequencies of afferent input during electrolocation and electrocommunication.

Action Potentials↗

Neuronal activity in somatosensory cortex of monkeys using a precision grip. II. Responses To object texture and weights.

Three monkeys were trained to lift and hold a test object within a 12- to 25-mm position window for 1 s. The activity of single neurons was recorded during performance of the task in which both the weight and surface texture of the object were systematically varied. Whenever possible, each cell was tested with three weights (15, 65, and 115 g) and three textures (smooth metal, fine 200 grit sandpaper, and rough 60 grit sandpaper). Of 386 cells recorded in 3 monkeys, 45 cells had cutaneous receptive fields on the index or thumb or part of the thenar eminence and were held long enough to be tested in all 9 combinations of texture and weight. Recordings were made for the entire anterior-posterior extent of the thumb and index finger areas in somatosensory cortex including area 7b. However, the statistical analysis required a selection of only those cells for which nine complete recording conditions were available limiting the sample to cells in areas 2, 5, and 7b. Significant differences in the grip force accompanied 98% of the changes in texture and 78% of the changes in weight. Increasing the object weight also increased the force tangential to the skin surface as measured by the load or lifting force. The peak discharge during lifting was judged to be the most sensitive index of cell activity and was analyzed with a two-way analysis of variance (ANOVA). In addition, peak cell discharge was normalized to allow comparisons among different combinations of texture and weight as well as comparisons among different neurons. Overall, the peak firing frequency of 87% of the cells was significantly modulated by changes in object texture, but changes in object weight affected the peak activity of only 58% of the cells. Almost all (17/18, 94%) of the static cells were influenced by the object texture, and 81% of the dynamic cells that were active only briefly at grip and lift onset were modulated by texture. For some cells, surface texture had a significant effect on neuronal discharge that was independent of the object weight. In contrast, weight-related responses were never simple main effects of the weight alone and appeared instead as significant interactions between texture and weight. Four neurons either increased or decreased activity in a graded fashion with surface structure (roughness) regardless of the object weight (P < 0.05). Ten other neurons showed increases or decreases in response to one or two textures, which might represent either a graded response or a tuning preference for a specific texture. The firing frequency of the majority (31/45) of neurons reflected an interaction of both texture and weight. The cells with texture-related but weight-independent activities were thought to encode surface characteristics that are largely independent of the grip and lifting forces used to manipulate the object. Such constancies could be used to construct internal representations or mental models for planning and controlling object manipulation.

Afferent Pathways↗

Mutations of the BRAF gene in human cancer.

Cancers arise owing to the accumulation of mutations in critical genes that alter normal programmes of cell proliferation, differentiation and death. As the first stage of a systematic genome-wide screen for these genes, we have prioritized for analysis signalling pathways in which at least one gene is mutated in human cancer. The RAS RAF MEK ERK MAP kinase pathway mediates cellular responses to growth signals. RAS is mutated to an oncogenic form in about 15% of human cancer. The three RAF genes code for cytoplasmic serine/threonine kinases that are regulated by binding RAS. Here we report BRAF somatic missense mutations in 66% of malignant melanomas and at lower frequency in a wide range of human cancers. All mutations are within the kinase domain, with a single substitution (V599E) accounting for 80%. Mutated BRAF proteins have elevated kinase activity and are transforming in NIH3T3 cells. Furthermore, RAS function is not required for the growth of cancer cell lines with the V599E mutation. As BRAF is a serine/threonine kinase that is commonly activated by somatic point mutation in human cancer, it may provide new therapeutic opportunities in malignant melanoma.

3T3 Cells↗

Integration of amino acid and carbon intermediary metabolism: studies with uniformly labeled tracers and mass isotopomer analysis.

The central pathways of metabolism include glycolysis and gluconeogenesis, fatty acid synthesis and beta-oxidation, the citric acid cycle and ureagenesis. Because these pathways intersect, changes in one pathway, due to inborn error or disease, affect pathways that may seem remote from the initial metabolic defect. These metabolic interrelationships also present difficulties for isotopic studies, because once carbon derived from isotopic tracers is introduced into metabolism it is extensively recycled. The use of multiple labeled (especially uniformly 13C-labeled ([U-13C]), metabolic tracers, in conjunction with mass isotopomer distribution analysis of mass and nuclear magnetic spectra, has enabled the development of methods that resolve some of these difficulties. Suitable choices of tracers and analytes allow the simultaneous measurement of multiple pathways and, importantly, their kinetic interrelationships. We illustrate three uses of the technique: (1) the unequivocal determination of trace fluxes; (2) the quantification of biosynthetic pathways: and (3) the dissection, in vivo, of the citric acid (Krebs) cycle. In each case, different combinations of [U-13C]tracer and metabolic end product have revealed metabolic phenomena that otherwise would remain unidentified. A particularly striking, and unexpected, observation that has emerged from recent studies using the technique, suggests that the key dehydrogenase reactions in the Krebs cycle may be reversible. Although this approach is of relatively recent development, it has already given a number of novel insights into the organization of the central metabolic pathways. It should provide a powerful method of investigating the metabolic impact of genetic disease and provide invaluable support of the assessment of new therapeutic interventions.

Amino Acids↗

Transcription analysis of arabidopsis membrane transporters and hormone pathways during developmental and induced leaf senescence.

A comparative transcriptome analysis for successive stages of Arabidopsis (Arabidopsis thaliana) developmental leaf senescence (NS), darkening-induced senescence of individual leaves attached to the plant (DIS), and senescence in dark-incubated detached leaves (DET) revealed many novel senescence-associated genes with distinct expression profiles. The three senescence processes share a high number of regulated genes, although the overall number of regulated genes during DIS and DET is about 2 times lower than during NS. Consequently, the number of NS-specific genes is much higher than the number of DIS- or DET-specific genes. The expression profiles of transporters (TPs), receptor-like kinases, autophagy genes, and hormone pathways were analyzed in detail. The Arabidopsis TPs and other integral membrane proteins were systematically reclassified based on the Transporter Classification system. Coordinate activation or inactivation of several genes is observed in some TP families in all three or only in individual senescence types, indicating differences in the genetic programs for remobilization of catabolites. Characteristic senescence type-specific differences were also apparent in the expression profiles of (putative) signaling kinases. For eight hormones, the expression of biosynthesis, metabolism, signaling, and (partially) response genes was investigated. In most pathways, novel senescence-associated genes were identified. The expression profiles of hormone homeostasis and signaling genes reveal additional players in the senescence regulatory network.

Arabidopsis↗

Gene expression analysis of troglitazone reveals its impact on multiple pathways in cell culture: a case for in vitro platforms combined with gene expression analysis for early (idiosyncratic) toxicity screening.

Peroxisome proliferator-activated receptor gamma (PPARgamma) agonists of the thiazolidinedione family are used for the treatment of type 2 diabetes mellitus due to their ability to reduce glucose and lipid levels in patients with this disease. Three thiazolidinediones that were approved for treatment are Rezulin (troglitazone), Avandia (rosiglitazone), and Actos (pioglitazone). Troglitazone was withdrawn from the market due to idiosyncratic drug toxicity. Rosiglitazone and pioglitazone are still on the market for the treatment of type 2 diabetes. The authors present data from a gene expression screen that compares the impact these three compounds have in rats, in rat hepatocytes, and in the clone 9 rat liver cell line. The authors monitored the changes in expression in multiple genes, including those related to xenobiotic metabolism, proliferation, DNA damage, oxidative stress, apoptosis, and inflammation. Compared to the other two compounds, troglitazone had a significant impact on many of the pathways monitored in vitro although no major perturbation was detected in vivo. The changes detected predict not only general toxicity but potential mechanisms of toxicity. Based on gene expression analysis, the authors propose there is not just one but multiple ways troglitazone could be toxic, depending on a patient's environment and genetic makeup, including immune response-related toxicity.

Animals↗

Analysis of the major mercapturic acid pathway metabolites of benzo[a]pyrene found in rat urine by nano-electrospray mass spectrometry.

Nano-electrospray has been used in combination with high resolution and tandem mass spectrometry in the analysis of the major mercapturic acid pathway metabolites of benzo[a]pyrene (BP). Accurate mass measurements indicate that the [M-H]- ion of the major metabolite has a chemical formula C25H22NO6S, which corresponds to the deprotonated form of tetrahydro-trihydroxy-BP-S-N-acetylcysteine. Tandem mass spectrometry of this [M-H]- ion results in a collision induced dissociation spectrum identical to that of synthetic 7,8,9,10-tetrahydro-8,9,10-trihydroxy-BP-7-S-N-acetylcysteine.

Acetylcysteine↗

Biochemical and genetic analysis of the gamma-resorcylate (2,6-dihydroxybenzoate) catabolic pathway in Rhizobium sp. strain MTP-10005: identification and functional analysis of its gene cluster.

We identified a gene cluster that is involved in the gamma-resorcylate (2,6-dihydroxybenzoate) catabolism of the aerobic bacterium Rhizobium sp. strain MTP-10005. The cluster consists of the graRDAFCBEK genes, and graA, graB, graC, and graD were heterologously expressed in Escherichia coli. Enzymological studies showed that graD, graA, graC, and graB encode the reductase (GraD) and oxygenase (GraA) components of a resorcinol hydroxylase (EC 1.14.13.x), a maleylacetate reductase (GraC) (EC 1.3.1.32), and a hydroxyquinol 1,2-dioxygenase (GraB) (EC 1.13.11.37). Bioinformatic analyses suggested that graE, graR, and graK encode a protein with an unknown function (GraE), a MarR-type transcriptional regulator (GraR), and a benzoate transporter (GraK). Quantitative reverse transcription-PCR of graF, which encodes gamma-resorcylate decarboxylase, revealed that the maximum relative mRNA expression level ([5.93 +/- 0.82] x 10(-4)) of graF was detected in the total RNA of the cells after one hour of cultivation when gamma-resorcylate was used as the sole carbon source. Reverse transcription-PCR of graDAFCBE showed that these genes are transcribed as a single mRNA and that the transcription of the gene cluster is induced by gamma-resorcylate. These results suggested that the graDAFCBE genes are responsible as an operon for the growth of Rhizobium sp. strain MTP-10005 on gamma-resorcylate and are probably regulated by GraR at the transcriptional level. This is the first report of the gamma-resorcylate catabolic pathway in an aerobic bacterium.

Base Sequence↗

Genetic analysis of plant disease resistance pathways.

Plant disease resistance (R) genes are introduced into high yielding crop varieties to improve resistance to agronomically important pathogens. The R gene-encoded proteins are recognitionally specific, interacting directly or indirectly with corresponding pathogen avirulence (avr) determinants, and are therefore under strong diversifying selection pressure to evolve new recognition capabilities. Genetic analyses in different plant species have also revealed more broadly recruited resistance signalling genes that provide further targets for manipulation in crop improvement strategies. Understanding the processes that regulate both plant-pathogen recognition and the induction of appropriate defences should provide fresh perspectives in combating plant disease. Many recent studies have utilized the model plant, Arabidopsis thaliana. Here, mutational screens have identified genes that are required for R gene function and for restriction of pathogen growth in compatible plant-pathogen interactions. Genetic analyses of these plant mutants suggest that whilst signalling pathways are conditioned by particular R protein structural types they are also influenced by pathogen lifestyle. Two Arabidopsis defence signalling genes, EDS1 and PAD4, are required for the accumulation of salicylic acid, a phenolic molecule required for systemic immunity. The cloning, molecular and biochemical characterization of these components suggests processes that may be important in their disease resistance signalling roles.

Arabidopsis↗

Rapid modulation of GABA in sensorimotor cortex induced by acute deafferentation.

Recovery of function after acute injury to the central nervous system may be controlled by the availability of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the cerebral cortex. Acute lesions as well as manipulation of sensory inputs can lead to rapid reorganization of the cerebral cortex, occurring within minutes to hours. Reduction of cortical inhibitory tone through a decrease in the availability of GABA has been suggested as a possible mechanism; however, the degree and temporal course of the changes in brain GABA are not known. A novel method using two-dimensional J-resolved magnetic resonance spectroscopy showed that GABA levels in the human sensorimotor cortex are quickly reduced within minutes of deafferentation. This finding strongly supports the view that the release of latent corticocortical projections from tonic inhibition through decreased GABA availability is a mechanism of rapid cortical plasticity. Reduction of brain GABA can play a pivotal role in regulating the extent of rapid cortical reorganization after lesions or changes in sensory input.

Adult↗

Cancer proteomics and its application to discovery of therapy response markers in human cancer.

The administration of chemotherapy either alone or in combination with radiotherapy is an important factor in reducing the mortality and morbidity of cancer patients. Resistance to both chemotherapy and radiotherapy represents a major obstacle to a successful outcome. The identification of novel biomarkers that can be used to predict treatment response would allow therapy to be tailored on an individual patient basis. Although the mechanisms are unclear, it is accepted that development of therapy resistance is a multifactorial phenomenon involving alterations in several cellular pathways. Proteome analysis methods are powerful tools for identifying factors associated with resistance to anticancer therapy because they facilitate the simultaneous analysis of whole proteomes. The current review describes the plethora of existing proteomic approaches and details the studies that have identified biomarkers that may be useful in the prediction of clinical response to anticancer therapy.

Biomarkers, Tumor↗

Dietary sodium chloride deprivation throughout development selectively influences the terminal field organization of gustatory afferent fibers projecting to the rat nucleus of the solitary tract.

In order to determine whether the developing central gustatory system responds to altered sensory experience, terminal fields of the chorda tympani nerve (CT) within the nucleus of the solitary tract (NTS) in control, NaCl deprived, and rats in which CT taste responses "recovered" from NaCl deprivation were investigated via anterograde transport of HRP. Rats fed a low sodium diet (0.03% NaCl) from the third day of gestation to at least 35 days postnatal exhibited both abnormally distributed and irregularly shaped CT terminal fields. Specifically, the dorsal zone of the field was the smallest in controls whereas it was the largest in deprived rats, occupying more medial and caudal territory within the nucleus. The portion of the field immediately ventral to the dorsalmost zone was characterized by a compact, oval shape in control rats and an irregular, broad configuration in deprived rats. Although it has been observed that deprivation-induced changes in the neurophysiology of the CT are reversible, the central morphological alterations reported here remain abnormal. Restoration of 1.0% NaCl in the diet at 28 days postnatally, for at least 60 days, did not result in normal CT terminal fields. The pattern of the field in rats "recovered" from NaCl deprivation was comparable to that found in deprived rats, and the size of the field was three times that found in control and deprived rats. The terminal fields of another nerve containing gustatory afferents, the lingual-tonsilar branch of the glossopharyngeal nerve (LT-IX), were studied for comparison. Interestingly, the pattern of the LT-IX field was not altered by sodium deprivation. The relative size and topography of the LT-IX fields in deprived rats were similar to controls. Thus, sodium deprivation appears to alter selectively the anatomical organization of the CT. Differences in vulnerability between the CT and LT-IX terminal fields may derive from differences in the responsiveness of these nerves to NaCl, and/or to differences in the timing of early neural events.

Afferent Pathways↗

The cerebellar deficient folia (cdf) gene acts intrinsically in Purkinje cell migrations.

Cerebellar deficient folia (cdf) is a recently identified mouse mutation causing ataxia and cerebellar abnormalities including lobulation defects and abnormal placement of a specific subset of Purkinje cells. To understand the etiology of the cerebellar defects in cdf mutant mice, we examined postnatal development of the cdf/cdf cerebellum. Our results demonstrate that Purkinje cell ectopia and foliation defects are apparent at birth, suggesting the cdf mutation disrupts the positioning of many, but not all, Purkinje cells during development. In addition to cerebellar abnormalities, we observed lamination defects in the hippocampus of cdf mutant mice, although neocortical defects were not seen. Furthermore, ectopic Purkinje cells in cdf/cdf mice express an increased level of Dab1 protein, as previously observed in mice with mutations in genes in the reelin signaling pathway. Lastly, analysis of cdf <-->ROSA26 chimeric mice demonstrated that the cdf mutation is intrinsic to Purkinje cells. We suggest that the cdf gene product is required in a subset of Purkinje cells, possibly to respond to Reelin signals.

Animals↗