Calbindin-1 Expression in the Hippocampus following Neonatal Hypoxia-Ischemia and Therapeutic Hypothermia and Deficits in Spatial Memory

Abstract

Hippocampal injury following neonatal hypoxia-ischemia (HI) leads to memory impairments despite therapeutic hypothermia (TH). In the hippocampus, the expression of calbindin-1 (Calb1), a Ca2+-buffering protein, increases during postnatal development and decreases with aging and neurodegenerative disorders. Since persistent Ca2+ dysregulation after HI may lead to ongoing injury, persistent changes in hippocampal expression of Calb1 may contribute to memory impairments after neonatal HI. We hypothesized that, despite TH, neonatal HI persistently decreases Calb1 expression in the hippocampus, a change associated with memory deficits in the mouse. We induced cerebral HI in C57BL6 mice at postnatal day 10 (P10) with right carotid ligation and 45 min of hypoxia (FiO2 = 0.08), followed by normothermia (36°C, NT) or TH (31°C) for 4 h with anesthesia-shams as controls. Nissl staining and glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) were used to grade brain injury and astrogliosis at P11, P18, and P40 prior to the assessment of Calb1 expression by IHC. The subset of mice followed to P40 also performed a memory behavior task (Y-maze) at P22–P26. Nonparametric statistics stratified by sex were applied. In both anterior and posterior coronal brain sections, hippocampal Calb1 expression doubled between P11 and P40 due to an increase in the cornus ammonis (CA) field (Kruskal-Wallis [KW] p < 0.001) and not the dentate gyrus (DG). Neonatal HI produced delayed (P18) and late (P40) deficits in the expression of Calb1 exclusively in the CA field (KW p = 0.02) in posterior brain sections. TH did not attenuate Calb1 deficits after HI. Thirty days after HI injury (at P40), GFAP scores in the hippocampus (p < 0.001, r = –0.47) and CA field (p < 0.001, r = –0.39) of posterior brain sections inversely correlated with their respective Calb1 expression. Both sexes demonstrated deficits in Y-maze testing, including approximately 40% lower spontaneous alterations performance and twice as much total impairment compared to sham mice (KW p < 0.001), but it was only in females that these deficits correlated with the Calb1 expression in the hippocampal CA field (p < 0.05) of the posterior sections. Hippocampal atrophy after neonatal HI also correlated with worse deficits in Y-maze testing, but it did not predict Calb1 deficits. Neonatal HI produces a long-lasting Calb1 deficit in the hippocampal CA field during development, which is not mitigated by TH. Late Calb1 deficit after HI may be the result of persistent astrogliosis and can lead to memory impairment, particularly in female mice.

Determination of a Tumor-Promoting Microenvironment in Recurrent Medulloblastoma: A Multi-Omics Study of Cerebrospinal Fluid

“…Another observation was a molecular signature indicative for hypoxia detected by proteome profiling ( Figure 3 B). In addition to the three significantly regulated proteins, the hypoxia-induced proteins CALB1 [ 47 ], as well as DDAH1 [ 48 ], were also found strongly up-regulated, yet not as uniform as the other three, thus lacking significance. This indication for MB-associated hypoxia was independently supported by the present metabolomics data demonstrating an up-regulation of tryptophan, methionine, serine and lysine ( Figure 4 B), in accordance with existing literature reporting a hypoxic adaptation of the cerebellum in association with the up-regulation of these amino acids [ 41 ].…”

Accumulation of PSA-NCAM marks nascent neurodegeneration in the dorsal hippocampus after neonatal hypoxic-ischemic brain injury in mice

“…39,40 In brief, mice were exposed to inhaled nitrous oxide/isoflurane 3% (induction, 30 s) and 1% (maintenance, 3–5 min) to perform right carotid artery ligation. After 1 h recovery with dam, mice were exposed to hypoxia (45 min, FiO 2 = 0.08), followed by randomization to normothermia (NT, 36°C) or TH (31°C) in isolation chambers (two to three mice per chamber) for 4 h. 2–4 Targeted temperature was achieved in 5–10 min and rewarming to 36°C occurred in ∼15 min. Rectal temperature monitoring (PowerLab, Ad Instruments, Inc., Colorado Springs, CO) was performed in one pup per treatment group per experiment using a rectal implantable thermocouple-microprobe.…”

“…This model also carries significant hippocampal injury variability. Thus, injury was assessed by Nissl staining and glial fibrillary acidic protein (GFAP) IHC, as previously reported, 1,2 to exclude animals with hippocampal obliteration (Supplemental methods: Table 1).…”

“…Neonatal hypoxia-ischemia (nHI) brain injury disrupts the normal GABAergic development in the mouse hippocampus 1,2 and leads to hippocampal atrophy and memory deficits. 2–4 While therapeutic hypothermia (TH), the standard of care for nHI encephalopathy (HIE) in children, protects motor aspects of neurodevelopment in humans 5,6 and in mouse models, 3 TH does not prevent memory deficits, suggesting ineffective hippocampal protection. 5,7–12 Supporting these findings, TH fails to persistently protect against hippocampal atrophy and GABAergic deficits in mice injured by nHI.…”

CALB1 enhances the interaction between p53 and MDM2, and inhibits the senescence of ovarian cancer cells

“…Calbindin 1 (CALB1) is a member of the calcium-binding protein superfamily that includes calmodulins and troponin C (16). CALB1 contains four active calcium-binding domains and two modified domains that are unable to bind calcium (17). CALB1 was demonstrated to regulate calcium influx following the activation of glutamate receptors (18).…”