Detection of pro-apoptotic Bax∆2 proteins in the human cerebellum

Mañas, Adriana; Davis, Aislinn; Lamerand, Sydney; Xiang, Jialing

doi:10.1007/s00418-018-1669-6

Cited by 6 publications

(6 citation statements)

References 23 publications

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“…Antibodies against total-Tau (T-Tau; D1M9X), phosphorylated Tau (P-Tau; T181), P-Tau (T205), TIA-1, and Bax (D2E11) were purchased from Cell Signaling Technology (Danvers, MA, USA); Bax (N20) was purchased from Santa Cruz Biotechnology (Dallas, TX, USA). The Bax∆2 monoclonal antibody (2D4), generated against amino acids (GFHGSSRANG) unique to Bax∆2, is well characterized, and was confirmed not to cross-react with Baxα in either immunostaining or immunoblotting [ 13 , 32 ].…”

Section: Methodsmentioning

confidence: 99%

Unconventional Source of Neurotoxic Protein Aggregation from Organelle Off-Target Bax∆2 in Alzheimer’s Disease

et al. 2023

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Protein aggregates are a hallmark of Alzheimer’s disease (AD). Extensive studies have focused on β-amyloid plaques and Tau tangles. Here, we illustrate a novel source of protein aggregates in AD neurons from organelle off-target proteins. Bax is a mitochondrial pore-forming pro-death protein. What happens to Bax if it fails to target mitochondria? We previously showed that a mitochondrial target-deficient alternatively spliced variant, Bax∆2, formed large cytosolic protein aggregates and triggered caspase 8-mediated cell death. Bax∆2 protein levels were low in most normal organs and the proteins were quickly degraded in cancer. Here, we found that 85% of AD patients had Bax∆2 required alternative splicing. Increased Bax∆2 proteins were mostly accumulated in neurons of AD-susceptible brain regions. Intracellularly, Bax∆2 aggregates distributed independently of Tau tangles. Interestingly, Bax∆2 aggregates triggered the formation of stress granules (SGs), a large protein-RNA complex involved in AD pathogenesis. Although the functional domains required for aggregation and cell death are the same as in cancer cells, Bax∆2 relied on SGs, not caspase 8, for neuronal cell death. These results imply that the aggregation of organelle off-target proteins, such as Bax∆2, broadens the scope of traditional AD pathogenic proteins that contribute to the neuronal stress responses and AD pathogenesis.

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Section: Methodsmentioning

confidence: 99%

Unconventional Source of Neurotoxic Protein Aggregation from Organelle Off-Target Bax∆2 in Alzheimer’s Disease

et al. 2023

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“…Skin FFPE (Formalin-Fixed Paraffin-Embedded) tissue microarray slides were obtained from Biomax (Cat# T211a and SK481) containing both normal and tumor adjacent tissues. The BaxΔ2 monoclonal antibody was generated and validated previously [12], [13]. Anti-Cytokeratin 14 (CK-14) antibody was purchased from Abcam.…”

Section: Methodsmentioning

confidence: 99%

“…Unlike most members of the pro-apoptotic Bax family which trigger apoptosis through the mitochondrial pathway, BaxΔ2 proteins are unable to target mitochondria, instead they accumulate in the cytosol as protein aggregates, activating caspase 8-dependent apoptosis [9]–[11]. Expression of BaxΔ2 protein in human tissues has been well characterized by immunohistochemistry with anti-BaxΔ2 antibody [12], [13]. Tissue distribution of BaxΔ2 is also different from that of Baxα: while Baxα is found abundantly and ubiquitously in almost all tissues including normal and cancerous tissue, BaxΔ2 is found in certain types of cells in normal and tumor adjacent normal tissues and rarely detected in malignant tumors [13].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to its typical distribution in the dermal connective tissue layer, most of the Bax∆2-positive cells lined up together at the bottom layer of epidermis [13]. Although the Bax∆2 antibody has been extensively validated and approved to be specific, we still wondered whether such strong positive staining is real Bax∆2 [12], [13]. It has been shown that melanin from basal cells is a brown color comparable to the brown oxidized deposits in DAB staining, resulting in a potential false-positive in DAB-based staining [14].…”

Section: Introductionmentioning

confidence: 99%

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Detection of melanin-mediated false-positive for BaxΔ2 immunohistochemical staining in human skin tissues

Basheer

Mañas

Yao

et al. 2020

Preprint

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BaxΔ2 is a pro-apoptotic isoform of the Bax family. We have previously shown that BaxΔ2 protein expression is low in most healthy human tissues with the protein mainly scattered in the connective tissues. Surprisingly, in skin tissue, the BaxΔ2-positive staining was strikingly strong, especially in the basal layer of the epidermis. It has been documented that melanin in the basal cells displays a brown color that could give false-positive staining in the commonly used DAB-based (3-3-diaminobenzidine) immunostaining. To avoid the false-positive staining from DAB-melanin, we performed immunofluorescent staining on the same set of tissues which were positive for BaxΔ2 in the DAB immunostaining. The results from co-immunofluorescent staining of BaxΔ2 and a basal cell marker CK-14 showed that the previously detected DAB-stained BaxΔ2-positive epidermal cells were CK-14 positive but BaxΔ2 negative. Consistent with our previous finding, the BaxΔ2-positive cells in the dermis connective tissues are positive in both DAB-based and fluorescence-based immunostainings. These data indicate that the DAB-stained BaxΔ2 positive cells in the basal layer of skin tissue are false-positive due to a misinterpretation of the melanin color, but the dermal connective tissue still presents real BaxΔ2 positive staining.

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“…One is the relatively more common mitochondria-dependent apoptosis pathway, which uses BH3-only protein as an "activator" to induce apoptosis (Sharikova et al, 2018). The other is the recently proposed non-mitochondrial-dependent apoptotic pathway, in this pathway, after receiving the apoptotic signal, the "sensitizers" represented by BAD and BIK in BH3-only protein will replace Bax and Bak on the anti-apoptotic protein through competition (Arimochi and Morita, 2006;Manas et al, 2018). Promote the release of Bax, Bak, and so on, thereby inhibiting the function of anti-apoptotic proteins through antagonism, leading to cell apoptosis.…”

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confidence: 99%

The antitumor activity of Bax BH3 peptide delivered by gold nanoparticles

Zhang

Qi²,

Wang³

et al. 2023

Front. Mater.

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Cancer has long remained one of the primary causes of disease and death globally, and it continues to pose a significant threat to human health. Surgery, radiotherapy, and chemotherapy are traditional treatments for cancer which are still widely used. However, while both surgery and radiotherapy remain acceptably effective in addressing a variety of primary tumors, neither possesses therapeutic potential for unknown metastatic lesions which may exist elsewhere in the patient’s body. Conversely, while systemic chemotherapy does have the potential for therapeutic efficacy on both primary and metastatic lesions alike, drug targeting is often poor, side effects are typically high, and treatment efficacy is still often lacking. Nanomedicine presents a promising solution to the above issues. For example, nanocarriers can be used to increase drug selectivity and targeting, increasing efficacy and decreasing side effects. Based on the role of the lethal domain of Bcl-2 family proteins, which play roles in apoptosis, the BH3-only protein, a section of BH3 peptide with a sequence of Asp-Ala-Ser-Thr-Lys-Lys-Leu-Ser-Glu-Cys-Leu-Arg-Arg-Ile-Gly-Asp-Glu-Leu-Asp-Ser. However, treatments based on soluble BH3 peptides, as with those based on other biologically active macromolecules, exhibit low cell membrane permeability, poor stability against proteolysis, and low endosomal escape rates. In this paper, attempt to address these issues by developing a variety of BH3@gold nanoparticle drug systems with different coating ratios. We demonstrate, high loading efficiency and, excellent anti-tumor effects in vitro, including inhibition of proliferation and migration in the human lung adenocarcinoma cell line, A549. Our results present a new possibility for anticancer peptide drugs in the future.

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Detection of pro-apoptotic Bax∆2 proteins in the human cerebellum

Cited by 6 publications

References 23 publications

Unconventional Source of Neurotoxic Protein Aggregation from Organelle Off-Target Bax∆2 in Alzheimer’s Disease

Unconventional Source of Neurotoxic Protein Aggregation from Organelle Off-Target Bax∆2 in Alzheimer’s Disease

Detection of melanin-mediated false-positive for BaxΔ2 immunohistochemical staining in human skin tissues

The antitumor activity of Bax BH3 peptide delivered by gold nanoparticles

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