Time course of SERCA 2b and calreticulin expression in Purkinje neurons of ethanol-fed rats with behavioral correlates

Biomarkers Identification in the Microenvironment of Oral Squamous Cell Carcinoma: A Systematic Review of Proteomic Studies

An important determinant for oral squamous cell carcinoma (OSCC) onset and outcome is the composition of the tumor microenvironment (TME). Thus, the study of the interactions occurring among cancer cells, immune cells, and cancer-associated fibroblasts within the TME could facilitate the understanding of the mechanisms underlying OSCC development and progression, as well as of its sensitivity or resistance to the therapy. In this context, it must be highlighted that the characterization of TME proteins is enabled by proteomic methodologies, particularly mass spectrometry (MS). Aiming to identify TME protein markers employable for diagnosing and prognosticating OSCC, we have retrieved a total of 119 articles spanning 2001 to 2023, of which 17 have passed the selection process, satisfying all its criteria. We have found a total of 570 proteins detected by MS-based proteomics in the TME of OSCC; among them, 542 are identified by a single study, while 28 are cited by two or more studies. These 28 proteins participate in extracellular matrix remodeling and/or energy metabolism. Here, we propose them as markers that could be used to characterize the TME of OSCC for diagnostic/prognostic purposes. Noteworthy, most of the 28 individuated proteins share one feature: being modulated by the hypoxia that is present in the proliferating OSCC mass.

Calsequestrin in Purkinje cells of mammalian cerebellum

Cerebellum is devoted to motor coordination and cognitive functions. Endoplasmic reticulum is the largest intracellular calcium store involved in all neuronal functions. Intralumenal calcium binding proteins play a pivotal role in calcium storage and contribute to both calcium release and uptake. Calsequestrin, a key calcium binding protein of sarco-endoplasmic reticulum in skeletal and cardiac muscles, was identified in chicken and fish cerebellum Purkinje cells, but its expression in mammals and human counterpart has not been studied in depth. Aim of the present paper was to investigate expression and localization of Calsequestrin in mammalian cerebellum. Calsequestrin was found to be expressed at low level in cerebellum, but specifically concentrated in Calbindin D28- and zebrin- immunopositive-Purkinje cells. Two additional fundamental calcium store markers, sarco-endoplasmic calcium pump isoform 2, SERCA2, and Inositol-trisphosphate receptor isoform 1, IP3R1, were found to be co-expressed in the region, with some localization peculiarities. In conclusion, a new marker was identified for Purkinje cells in adult mammals, including humans. Such a marker might help in staminal neuronal cells specification and in dissection of still unknown neurodegeneration and physio-pathological effects of dysregulated calcium homeostasis.

Potential Role of MANF, an ER Stress Responsive Neurotrophic Factor, in Protecting Against Alcohol Neurotoxicity

Alcohol exposure during pregnancy is harmful to the fetus and causes a wide range of long-lasting physiological and neurocognitive impairments, collectively referred to as fetal alcohol spectrum disorders (FASD). The neurobehavioral deficits observed in FASD result from structural and functional damages in the brain, with neurodegeneration being the most destructive consequence. Currently, there are no therapies for FASD. It is exigent to delineate the underlying mechanisms of alcohol neurotoxicity and develop an effective strategy of treatment. ER stress, caused by the accumulation of unfolded/misfolded proteins in the ER, is the hallmark of many neurodegenerative diseases, including alcohol-induced neurodegeneration. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a newly discovered endoplasmic reticulum (ER) stress responsive neurotrophic factor that regulates diverse neuronal functions. This review summarizes the recent findings revealing the effects of MANF on the CNS and its protective role against neurodegeneration. Particularly, we focus the role of MANF on alcohol-induced ER stress and neurodegeneration and discuss the therapeutic potential of MANF in treating alcohol neurotoxicity such as FASD.

Memantine can improve chronic ethanol exposure-induced spatial memory impairment in male C57BL/6 mice by reducing hippocampal apoptosis

Chronic ethanol intake can induce neuronal apoptosis, leading to dementia. We investigated the protective effects of memantine on spatial memory impairment induced by chronic ethanol exposure in mice. Male C57BL/6 mice were administered 10% (m/V) or 20% (m/V) ethanol as the only choice of drinking water. Mice were treated for 60 d, 90 d, or 180 d. Mice were treated with memantine for the same duration (daily 10 mg/kg oral). The Morris water maze and radial arm maze test were used to measure spatial memory. Mice were sacrificed after the behavioral tests. Brains were removed to prepare for paraffin sections, and hippocampi were isolated for protein and RNA extraction. 4',6-diamidino-2-phenylindole (DAPI) staining and immunohistochemical staining of cleaved caspase-3 were performed. Western blot analysis was used to detect the expression of cleaved caspase-3 and calcium-related proteins, including N-methyl-d-aspartic acid receptor 1 (NR1), 1,4,5-trisphosphate receptor 1 (IP3R1), and sarco/endoplasmic reticulum calcium adenosine triphosphatase 1 (SERCA1). The changes of NR1, IP3R1 and SERCA1 mRNA were detected using quantitative polymerase chain reaction (qPCR). The results revealed that chronic ethanol exposure induced spatial memory impairment in mice, as well as increasing the expression of NR1, IP3R1 and SERCA1, the activation of caspase-3 and apoptosis in hippocampus. The effect was particularly prominent in the 20% ethanol group after 180 d exposure. Memantine decreased ethanol-induced spatial memory impairment, caspase-3 activation and apoptosis in the mouse hippocampus. These results suggest that disruption of intracellular calcium balance by ethanol can induce caspase-3 activation and apoptosis, which underlies subsequent spatial memory impairment in mice.

The SERCA2: A Gatekeeper of Neuronal Calcium Homeostasis in the Brain

Calcium (Ca2+) ions are prominent cell signaling regulators that carry information for a variety of cellular processes and are critical for neuronal survival and function. Furthermore, Ca2+ acts as a prominent second messenger that modulates divergent intracellular cascades in the nerve cells. Therefore, nerve cells have developed intricate Ca2+ signaling pathways to couple the Ca2+ signal to their biochemical machinery. Notably, intracellular Ca2+ homeostasis greatly relies on the rapid redistribution of Ca2+ ions into the diverse subcellular organelles which serve as Ca2+ stores, including the endoplasmic reticulum (ER). It is well established that Ca2+ released into the neuronal cytoplasm is pumped back into the ER by the sarco-/ER Ca2+ ATPase 2 (SERCA2), a P-type ion-motive ATPase that resides on the ER membrane. Even though the SERCA2 is constitutively expressed in nerve cells, its precise role in brain physiology and pathophysiology is not well-characterized. Intriguingly, SERCA2-dependent Ca2+ dysregulation has been implicated in several disorders that affect cognitive function, including Darier's disease, schizophrenia, Alzheimer's disease, and cerebral ischemia. The current review summarizes knowledge on the expression pattern of the different SERCA2 isoforms in the nervous system, and further discusses evidence of SERCA2 dysregulation in various neuropsychiatric disorders. To the best of our knowledge, this is the first literature review that specifically highlights the critical role of the SERCA2 in the brain. Advancing knowledge on the role of SERCA2 in maintaining neuronal Ca2+ homeostasis may ultimately lead to the development of safer and more effective pharmacotherapies to combat debilitating neuropsychiatric disorders.

Age-related alterations in histone deacetylase expression in Purkinje neurons of ethanol-fed rats

Ethanol and age-induced pathologies of the Purkinje neuron (PN) may result from histone deacetylases (HDACs), enzymes which repress transcription through coiling of the DNA. The purposes of this study were to investigate expression patterns of Class 1 and IIa HDACs in PN and the effects of aging and alcohol on the density of HDACs and histone acetylation in PN. Ninety, eight month old rats (30/diet) were fed a liquid ethanol, liquid control, or rat chow diet for 10, 20, or 40weeks (30/treatment duration). Double immunocytochemical labeling on tissue sections from these rats used antibodies against HDAC isoforms or acetylated histones, and calbindin, a marker for PN. Fluorescent intensities were also measured. Results showed a significant age but not an alcohol-related decrease in the densities of HDACs 2, 3, and 7. In contrast, there were age related-increases in the densities of phosphorylated form of HDAC (4, 5, 7) PN and in PN nuclei expressing HDAC 7. There were also a trend towards ethanol-induced inhibition of acetylation as the density of AH2b PN nuclei and AH3 and AH2b fluorescent intensity was significantly lower in the EF compared to the PF rats. This study presents unique data concerning which HDACs are commonly expressed in PN and indicates that aging rather than lengthy alcohol expression alters expression of the HDACs studied here. These results also suggest that lengthy ethanol consumption may inhibit histone deacetylation in PN.

Ethanol-Induced Alterations in Purkinje Neuron Dendrites in Adult and Aging Rats: a Review

Uncomplicated alcoholics suffer from discrete motor dysfunctions that become more pronounced with age. These deficits involve the structure and function of Purkinje neurons (PN), the sole output neurons from the cerebellar cortex. This review focuses on alterations to the PN dendritic arbor in the adult and aging Fischer 344 rat following lengthy alcohol consumption. It describes seminal studies using the Golgi-Cox method which proposed a model for ethanol-induced dendritic regression. Subsequent ultrastructural studies of PN dendrites showed dilation of the extensive smooth endoplasmic reticulum (SER) which preceded and accompanied dendritic regression. The component of the SER that was most affected by ethanol was the sarco/endoplasmic reticulum Ca(2+) ATPase pump (SERCA) responsible for resequestration of calcium into the SER. Ethanol-induced decreases in SERCA pump levels, similar to the finding of SER dilation, preceded and occurred concomitantly with dendritic regression. Discrete ethanol-induced deficits in balance also accompanied these decreases. Ethanol-induced ER stress within the SER of PN dendrites was proposed as an underlying cause of dendritic regression. It was recently shown that increased activation of caspase 12, inherent to the ER, occurred in PN of acute slices in ethanol-fed rats and was most pronounced following 40 weeks of ethanol treatment. These findings shed new light into alcohol-induced disruption in PN dendrites providing a new model for the discrete but critical changes in motor function in aging, adult alcoholics.

ATF6 and caspase 12 expression in Purkinje neurons in acute slices from adult, ethanol-fed rats

The purpose of this study was to determine, whether previously reported ethanol-induced alterations to the smooth endoplasmic reticulum (SER), predispose Purkinje neurons (PN) to thapsigargin-induced endoplasmic reticulum (ER) stress. Thapsigargin blocks the sarco/endoplasmic Ca(2+) ATPase pump (SERCA 2), depleting the SER of calcium. Forty-one, eight month old Fischer 344 male rats were treated with either the AIN (American Institute of Nutrition) liquid control or ethanol diets for 10 (n=14), 20 (n=10), or 40(n=17) weeks. At the end of treatment, acute cerebellar slices were prepared by standard means. Cerebellar slices were treated with thapsigargin or as controls for three hours in oxygenated (95% CO2, 5% O2) ACSF (artificial cerebrospinal fluid). Slices were then fixed in 4% paraformaldehyde and sectioned on a freezing microtome. Free floating sections were stained with antibodies against activating transcription factor 6 (ATF6) or activated caspase 12 and calbindin. Results showed a significant increase in the activated caspase+PN dendrites in the EF rats along with a significant interaction due to enhanced expression of activated caspase 12 at 20 weeks. The density of ATF6 labeling was not different between the EF and PF groups and was confined to the PN soma. The finding of activated caspase and ATF6 expression in PN within both the EF and PF groups supports the finding of thapsigargin-induced ER stress. The finding of increased activated caspase 12 in the dendrites supports an increased tendency to ER stress and other dendritic deficits in the ethanol rats.