In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field
2-Chloro-10-[3(-dimethylamino)propyl]phenothiazine mono hydrochloride (chlorpromazine; CPZ) is an antipsychotic agent that was originally developed to control psychotic disorders. The cytotoxic properties of the CPZ are well known, but its mechanism of action is poorly understood. In this study, we investigated the role of apoptosis and autophagy in CPZ-induced cytotoxicity in U-87MG glioma cells. CPZ treatment inhibited cell proliferation and long-term clonogenic survival. Additionally, CPZ triggered autophagy, as indicated by electron microscopy and accumulation of the membrane form of microtubule-associated protein 1 light chain 3 (LC3-II); however, CPZ did not induce apoptosis. Inhibition of autophagy by expression of Beclin 1 small interfering RNA (siRNA) in U-87MG cells attenuated CPZ-induced LC3-II formation. Furthermore, U-87MG cells expressing Beclin 1 siRNA attenuated CPZ-induced cell death. CPZ inhibited phosphatidylinositol 3-kinase (PI3K)/AKT/ mTOR pathway in U-87MG cells. Treatment with LY294002, a PI3K inhibitor, alone increased the accumulation of LC3-II and potentiated the effect of CPZ. In contrast, exogenous expression of AKT partially inhibited CPZ-induced LC3-II formation. When U-87MG cells were implanted into the brain of athymic nude mouse, CPZ triggered autophagy and inhibited xenograft tumor growth. These results provided the first evidence that CPZ-induced cytotoxicity is mediated through autophagic cell death in PTEN (phosphatase and tensin homolog deleted on chromosome 10)-null U-87MG glioma cells by inhibiting PI3K/AKT/mTOR pathway.
Various mediators, including cytokines, growth factors, homeotic gene products, and prostaglandins (PGs), participate in the implantation process in an autocrine, paracrine, or juxtacrine manner. However, interactions among these factors that result in successful implantation are not clearly understood. Leukemia inhibitory factor (LIF), a pleiotropic cytokine, was shown to be expressed in uterine glands on day 4 morning before implantation and is critical to this process in mice. However, the mechanism by which LIF executes its effects in implantation remains unknown. Moreover, interactions of LIF with other implantation-specific molecules have not yet been defined. Using normal and delayed implantation models, we herein show that LIF is not only expressed in progesterone (P4)-primed uterine glands before implantation in response to nidatory estrogen, it is also induced in stromal cells surrounding the active blastocyst at the time of the attachment reaction. This suggests that LIF has biphasic effects: first in the preparation of the receptive uterus and subsequently in the attachment reaction. The mechanism by which LIF participates in these events was addressed using LIF-deficient mice. We observed that while uterine cell-specific proliferation, steroid hormone responsiveness, and expression patterns of several genes are normal, specific members of the EGF family of growth factors, such as amphiregulin (Ar), heparin-binding EGF-like growth factor (HB-EGF), and epiregulin, are not expressed in LIF(-/-) uteri before and during the anticipated time of implantation, although EGF receptor family members (erbBs) are expressed correctly. Furthermore, cyclooxygenase-2 (COX-2), an inducible rate-limiting enzyme for PG synthesis and essential for implantation, is aberrantly expressed in the uterus surrounding the blastocyst in LIF(-/-) mice. These results suggest that dysregulation of specific EGF-like growth factors and COX-2 in the uterus contributes, at least partially, to implantation failure in LIF(-/-) mice. Since estrogen is essential for uterine receptivity, LIF induction, and blastocyst activation, it is possible that the nidatory estrogen effects in the P4-primed uterus for implantation are mediated via LIF signaling. However, we observed that LIF can only partially resume implantation in P4-primed, delayed implanting mice in the absence of estrogen, suggesting LIF induction is one of many functions that are executed by estrogen for implantation.
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