Autophagy and apoptosis are basic physiologic processes contributing to the maintenance of cellular homeostasis. Autophagy encompasses pathways that target long-lived cytosolic proteins and damaged organelles. It involves a sequential set of events including double membrane formation, elongation, vesicle maturation and finally delivery of the targeted materials to the lysosome. Apoptotic cell death is best described through its morphology. It is characterized by cell rounding, membrane blebbing, cytoskeletal collapse, cytoplasmic condensation, and fragmentation, nuclear pyknosis, chromatin condensation/fragmentation, and formation of membrane-enveloped apoptotic bodies, that are rapidly phagocytosed by macrophages or neighboring cells. Neurodegenerative disorders are becoming increasingly prevalent, especially in the Western societies, with larger percentage of members living to an older age. They have to be seen not only as a health problem, but since they are care-intensive, they also carry a significant economic burden. Deregulation of autophagy plays a pivotal role in the etiology and/or progress of many of these diseases. Herein, we briefly review the latest findings that indicate the involvement of autophagy in neurodegenerative diseases. We provide a brief introduction to autophagy and apoptosis pathways focusing on the role of mitochondria and lysosomes. We then briefly highlight pathophysiology of common neurodegenerative disorders like Alzheimer's diseases, Parkinson's disease, Huntington's disease and Amyotrophic lateral sclerosis. Then, we describe functions of autophagy and apoptosis in brain homeostasis, especially in the context of the aforementioned disorders. Finally, we discuss different ways that autophagy and apoptosis modulation may be employed for therapeutic intervention during the maintenance of neurodegenerative disorders.
Rat adrenomedullin is a novel 50-amino acid peptide with structural similarities to the calcitonin family of peptides, calcitonin, calcitonin gene-related peptide (CGRP), and islet amyloid polypeptide (IAPP). Using rat [125I]adrenomedullin, specific binding sites were demonstrated in heart, lung, spleen, liver, soleus, diaphragm, gastrocnemius, and spinal cord membranes. The highest binding was present in heart and lung, which was further characterized. These sites exhibited saturation, dissociation, and competition. In rat lung, only rat (IC50 = 5.8 nM) and human (IC50 = 94 nM) adrenomedullin competed with [125I]adrenomedullin. However, in rat heart, rat (IC50 = 0.2 nM) and human (IC50 = 4.2 nM) adrenomedullin, IAPP (IC50 = 240 nM), and CGRP (IC50 = 1050 nM) all competed with [125I] adrenomedullin. Saturation analysis revealed binding capacities and dissociation constants of 2.8 +/- 0.3 pmol/mg protein and 1.3 +/- 0.3 nM, respectively, in lung and 0.47 +/- 0.11 pmol/mg protein and 0.41 +/- 0.14 nM in heart. Comparison with [125I]CGRP- and [125I]IAPP-binding sites in lung showed that rat adrenomedullin could potently inhibit at these sites (IC50 = 5 and 6 nM, respectively). Chemical cross-linking demonstrated a major band of 83,000 mol wt in lung, diaphragm, spleen, and liver and a band of 94,000 mol wt in heart, soleus, and gastrocnemius. Thus, [125I]adrenomedullin-binding sites in rat lung are abundant and can be differentiated from binding sites in rat heart, both pharmacologically and by mol wt.
Glucagon-like peptide-1 7-36 amide (GLP-1) has been postulated to be the primary hormonal mediator of the enteroinsular axis but evidence has been indirect. The discovery of exendin (9-39), a GLP-1 receptor antagonist, allowed this to be further investigated. The IC5o for GLP-1 receptor binding, using RIN 5AH fl-cell membranes, was found to be 0.36 nmol/l for GLP-1 and 3.44 nmol/l for exendin (9-39). There was no competition by exendin (9-39) at binding sites for glucagon or related peptides. In the anaesthetized fasted rat, insulin release after four doses of GLP-1 (0.1, 0.2, 0.3, and 0.4 nmol/kg) was tested by a 2-min intravenous infusion. Exendin (9-39) (1.5, 3.0, and 4.5 nmol/kg) was administered with GLP-1 0.3 nmol/kg, or saline, and only the highest dose fully inhibited insulin release. Exendin (9-39) at 4.5 nmol/kg had no effect on glucose, arginine, vasoactive intestinal peptide or glucose-dependent insulinotropic peptide stimulated insulin secretion. Postprandial insulin release was studied in conditioned conscious rats after a standard meal. Exendin (9-39) (0.5 nmol/kg) considerably reduced postprandial insulin concentrations, for example by 48% at 15 min (431±21 pmol/ I saline, 224±32 pmol/l exendin, P < 0.001). Thus, GLP-1 appears to play a major role in the entero-insular axis. (J. Clin. Invest. 1995.95:417-421.)
Colorectal cancer (CRC), despite numerous therapeutic and screening attempts, still remains a major life-threatening malignancy. CRC etiology entails both genetic and environmental factors. Macroautophagy/autophagy and the unfolded protein response (UPR) are fundamental mechanisms involved in the regulation of cellular responses to environmental and genetic stresses. Both pathways are interconnected and regulate cellular responses to apoptotic stimuli. In this review, we address the epidemiology and risk factors of CRC, including genetic mutations leading to the occurrence of the disease. Next, we discuss mutations of genes related to autophagy and the UPR in CRC. Then, we discuss how autophagy and the UPR are involved in the regulation of CRC and how they associate with obesity and inflammatory responses in CRC. Finally, we provide perspectives for the modulation of autophagy and the UPR as new therapeutic options for CRC treatment.
Rat adrenomedullin is a novel 50-amino acid peptide with structural similarities to the calcitonin family of peptides, calcitonin, calcitonin gene-related peptide (CGRP), and islet amyloid polypeptide (IAPP). Using rat [125I]adrenomedullin, specific binding sites were demonstrated in heart, lung, spleen, liver, soleus, diaphragm, gastrocnemius, and spinal cord membranes. The highest binding was present in heart and lung, which was further characterized. These sites exhibited saturation, dissociation, and competition. In rat lung, only rat (IC50 = 5.8 nM) and human (IC50 = 94 nM) adrenomedullin competed with [125I]adrenomedullin. However, in rat heart, rat (IC50 = 0.2 nM) and human (IC50 = 4.2 nM) adrenomedullin, IAPP (IC50 = 240 nM), and CGRP (IC50 = 1050 nM) all competed with [125I] adrenomedullin. Saturation analysis revealed binding capacities and dissociation constants of 2.8 +/- 0.3 pmol/mg protein and 1.3 +/- 0.3 nM, respectively, in lung and 0.47 +/- 0.11 pmol/mg protein and 0.41 +/- 0.14 nM in heart. Comparison with [125I]CGRP- and [125I]IAPP-binding sites in lung showed that rat adrenomedullin could potently inhibit at these sites (IC50 = 5 and 6 nM, respectively). Chemical cross-linking demonstrated a major band of 83,000 mol wt in lung, diaphragm, spleen, and liver and a band of 94,000 mol wt in heart, soleus, and gastrocnemius. Thus, [125I]adrenomedullin-binding sites in rat lung are abundant and can be differentiated from binding sites in rat heart, both pharmacologically and by mol wt.
Background Human leptin is a peptide hormone that is released from white adipocytes. The absence of leptin or its receptor leads to uncontrolled food intake, leading to obesity. In the present work, the effects of auricular acupressure combined with low-calorie diet on the leptin hormone level were investigated. Methods Volunteers (n=86) with body mass indices (BMI) between 25 and 45 kg/m 2 were randomised into a case (n=43) or a control (n=43) group. Participants in each group received a low-calorie diet for 6 weeks. The case group was treated with auricular acupressure and the control group received a sham procedure. Plasma leptin levels, body fat mass, body weight and BMI were measured before and after treatment. Results Participants who received auricular acupressure showed signifi cant reductions in their plasma leptin levels (18.57%, p<0.01) as well as in their body fat mass (4%, p<0.05). These changes were not observed in the control group. The reduction in leptin was signifi cantly greater in the acupressure group than the controls. Conclusions Auricular acupressure combined with a low-calorie diet signifi cantly reduced plasma levels of leptin. However, the mechanism of this reduction is not clear.
BackgroundThe prevalence of abdominal obesity is on the rise worldwide. Previous studies have indicated the higher diagnostic value of body fat distribution pattern compared with general body in abdominal obesity assessments. Several non-pharmacological methods have been suggested for obesity management, of which acupuncture has gained a great deal of research interest with promising results.This study aimed to comparatively evaluate the effects of conventional auricular and body electroacupuncture on abdominal fat mass in obese men.MethodsThe volunteers were randomly divided into four groups, including 2 interventions and 2 controls. This study was conducted on 80 obese volunteer men with Body Mass Index (BMI) range of 30–40 kg/m2.The intervention groups including real body electroacupuncture (A), real auricular acupuncture (C) and the control groups containing sham body electroacupuncture (B), and sham auricular acupuncture (D). All groups were in combination with a low-calorie diet for 6 weeks. BMI, Trunk Fat Mass (TFM), Waist Circumference (WC), and Hip Circumference (HC) were measured pre- and post-intervention.ResultsIn group A, respectively a significant reduction was shown in BMI (P < 0.005), TFM (P < 0.005), WC (P < 0.05, P < 0.005) and HC (P < 0.005) when compared with controls (Groups B and D). Interestingly, group C had significant decreases in BMI (P < 0.005), TFM (P < 0.01, P < 0.005), WC (P < 0.005) and HC (P < 0.001) after comparison with the sham. Likewise, WC (P < 0.05) and HC (P < 0.05) were significantly reduced post- intervention when compared with two treatment groups.ConclusionsIn our study, acupuncture treatment (body or auricular) seemed to have an effect on reducing BMI, TFM, WC and HC. Comparison of the two types of treatment (body and auricular acupuncture) suggests that the two types of acupuncture had similar effects on reducing BMI and TFM, but body electroacupuncture is more effective in reducing WC and auricular in HC. It seems that both auricular and body electro-acupuncture combined with a low-calorie diet are efficient, simple and painless methods to reduce respectively the HC and WC fat in obese men, compared with conventional techniques.Trial registrationIRCT201201127117N2
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