CIDEA — Cell Death-Inducing DFFA-Like Effector A

CIDEA — Cell Death-Inducing DFFA-Like Effector A
Tissue	Expression Level
Brown adipose tissue	Highest
Liver	High
Brain	Low-Moderate
Heart	Moderate
Kidney	Low
KG Connections	1 edges

Overview

CIDEA (Cell Death-Inducing DFFA-Like Effector A) is a member of the CIDE (Cell Death-Inducing DFFA-like Effector) family of proteins that play important roles in regulating cell death, lipid metabolism, and energy homeostasis. The gene is located on chromosome 18p11.21 and encodes a protein primarily associated with lipid droplets in cells. ^{1Profile.1999 · Pharm Sci Technol Today · PMID 10498923Open reference} CIDEA is highly expressed in brown adipose tissue, where it promotes lipid droplet formation and regulates thermogenesis. The protein is also expressed in the liver and other tissues, where it influences metabolic processes.

Beyond its well-characterized role in metabolic tissues, CIDEA has emerging relevance to neurodegenerative diseases. The brain relies on lipid metabolism for proper neuronal function, and dysregulated lipid homeostasis is a hallmark of Alzheimer’s disease (AD), Parkinson’s disease (PD), and other neurodegenerative conditions. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference} This page covers CIDEA’s normal functions, disease associations, expression patterns, and potential implications for neurodegeneration.

Structure and Function

Protein Architecture

CIDEA is a 175-amino acid protein with a unique structure characterized by a CIDE-N domain at the N-terminus and a CIDE-C domain at the C-terminus. These domains are shared with other CIDE family members (CIDEB and CIDEC/FSP27) and are involved in protein-protein interactions and lipid droplet targeting. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}

The CIDE-N domain (approximately 80 amino acids) mediates homodimerization and heterodimerization with other CIDE family members. This dimerization is essential for the protein’s lipid droplet localization and function. The CIDE-C domain (~70 amino acids) interacts with various binding partners and contributes to the protein’s pro-apoptotic activity. ^{4Cell death, dysglycemia and myocardial infarction.2013 · Biomed Rep · DOI 10.3892/br.2013.67 · PMID 24648945Open reference}

Subcellular Localization

CIDEA is primarily localized to lipid droplets, which are dynamic organelles storing neutral lipids including triglycerides and cholesterol esters. The protein localizes to the surface of lipid droplets through interactions with the phospholipid monolayer. In addition to lipid droplets, CIDEA can also be found in the cytoplasm and, under certain conditions, in the nucleus. ^{5From disease to etiology: historical aspects of Chlamydia-related diseases in animals and humans.2009 · Drugs Today (Barc) · PMID 20011706Open reference}

The lipid droplet localization of CIDEA is dynamic and regulated by nutritional status, hormonal signals, and cellular stress. During fasting, CIDEA expression increases and promotes lipid droplet accumulation, while in the fed state, the protein may be downregulated to facilitate lipid mobilization. ^{6Parkinson's disease.2016 · Lancet · DOI doi: 10.1016/S0140-6736(16)00049-0 · PMID 26842286Open reference}

Normal Physiological Functions

Regulation of Cell Death

Originally identified as a regulator of apoptosis, CIDEA interacts with the Fas receptor and inhibits apoptosis in certain cellular contexts. The protein can associate with DFF45 (DNA fragmentation factor subunit beta), an inhibitor of CAD (caspase-activated DNase), thereby modulating the apoptotic cascade. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}

However, the pro-apoptotic versus anti-apoptotic functions of CIDEA appear to be context-dependent. In some settings, CIDEA promotes cell death, while in others it provides survival advantages. This duality reflects the protein’s complex interactions with multiple signaling pathways. ^{7Developmental origins of adult diseases.2022 · Med Rev (2021) · DOI doi: 10.1515/mr-2022-0027 · PMID 37724166Open reference}

Lipid Metabolism and Thermogenesis

CIDEA plays a central role in lipid metabolism, particularly in brown adipose tissue (BAT). Brown fat is specialized for non-shivering thermogenesis, generating heat through uncoupled mitochondrial respiration. CIDEA promotes lipid droplet formation and accumulation in brown adipocytes, providing substrate for thermogenesis. ^{8Response.2019 · Med Sci Sports Exerc · DOI doi: 10.1249/MSS.0000000000002114 · PMID 31725090Open reference}

The protein interacts with uncoupling protein 1 (UCP1) in the mitochondrial inner membrane to enhance proton leak and heat production. Studies in mice have shown that CIDEA overexpression in white adipose tissue induces “browning” - the conversion of white adipocytes to brown-like cells with increased thermogenic capacity. ^{9Lipometabolism and Glycometabolism in Liver Diseases.2018 · Biomed Res Int · DOI doi: 10.1155/2018/1287127 · PMID 31205932Open reference}

Hepatic Function

In the liver, CIDEA regulates lipid droplet dynamics and contributes to hepatic lipid homeostasis. Loss of CIDEA in mice leads to hepatic steatosis (fatty liver), decreased VLDL (very-low-density lipoprotein) secretion, and premature death when combined with CIDEB knockout. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}0

CIDEA affects hepatic lipid metabolism through multiple mechanisms:

• Promoting lipid droplet formation and storage

• Regulating lipolysis and fatty acid oxidation

• Modulating VLDL assembly and secretion

• Influencing autophagy and lipid turnover

Autophagy Regulation

Recent research has revealed that CIDEA plays a role in regulating autophagy, the cellular recycling process that degrades damaged organelles and protein aggregates. CIDEA can interact with autophagy-related proteins and influence the formation of autophagosomes. In cancer cells, CIDEA has been shown to regulate autophagy and lipid metabolism through AMPK signaling. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}1

This function has implications for neurodegeneration, where impaired autophagy contributes to the accumulation of toxic protein aggregates.

Role in Neurodegeneration

Lipid Droplet Accumulation in Neurodegeneration

The brain contains lipid droplets that accumulate in neurons and glia under various pathological conditions. In Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative disorders, lipid droplet accumulation is increasingly recognized as a key pathological feature. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}2

Several mechanisms contribute to lipid droplet accumulation in neurodegeneration:

• Impaired fatty acid oxidation and mitochondrial dysfunction

• Dysregulated lipid synthesis and uptake

• Impaired autophagy and lipophagy

• Neuroinflammation and glial lipid metabolism alterations

CIDEA, as a lipid droplet-associated protein, may influence these processes and contribute to or protect against neurodegeneration. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}3

Alzheimer’s Disease

Alzheimer’s disease is characterized by amyloid-beta (Aβ) plaques, neurofibrillary tangles composed of hyperphosphorylated tau, and progressive neuronal loss. Lipid metabolism dysfunction is increasingly recognized as an important contributor to AD pathogenesis. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}4

In AD brains, altered expression of lipid droplet-associated proteins has been reported, potentially affecting Aβ metabolism, tau phosphorylation, and neuronal survival. While direct evidence for CIDEA involvement in AD is limited, the protein’s functions in lipid metabolism and autophagy suggest potential relevance. Studies have shown that improving lipid droplet dynamics can protect against Aβ toxicity in cellular models. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}5

The APOE ε4 allele, the major genetic risk factor for late-onset AD, is involved in lipid transport and metabolism, highlighting the importance of lipid homeostasis in AD pathogenesis. CIDEA and other lipid droplet proteins may interact with APOE-related pathways. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}6

Parkinson’s Disease

Parkinson’s disease is characterized by loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies composed of α-synuclein. Lipid metabolism alterations have been implicated in PD pathogenesis, and lipid droplets accumulate in affected brain regions. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}7

CIDEA may influence PD pathogenesis through effects on:

• Mitochondrial function and oxidative stress

• α-synuclein aggregation and clearance

• Neuroinflammation in glial cells

• Autophagy-lysosome pathway function

Amyotrophic Lateral Sclerosis

In ALS, lipid droplet accumulation has been observed in motor neurons and surrounding glia. The protein TDP-43 forms cytoplasmic inclusions in most ALS cases, and lipid metabolism alterations may affect TDP-43 aggregation and toxicity. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}8

Potential Mechanisms

Several pathways connect CIDEA to neurodegeneration:

1. Autophagy and protein clearance: CIDEA’s role in autophagy regulation could affect clearance of toxic protein aggregates (Aβ, tau, α-synuclein, TDP-43).

2. Mitochondrial function: CIDEA influences mitochondrial metabolism and could affect neuronal energy homeostasis and oxidative stress resistance.

3. Neuroinflammation: Lipid droplet accumulation in glial cells promotes inflammatory responses. CIDEA expression in immune cells could modulate neuroinflammation. ^{2Bio-related applications of porous organic frameworks (POFs).2019 · J Mater Chem B · DOI doi: 10.1039/c8tb03192d · PMID 32255118Open reference}9

4. Oxidative stress: Lipid droplets both sequester and generate reactive oxygen species (ROS). CIDEA may influence oxidative stress in neurons through lipid droplet dynamics. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}0

Expression Patterns

In the brain, CIDEA is expressed in various regions including the cortex, hippocampus, and cerebellum. The protein is present in both neurons and glial cells, with potential upregulation under pathological conditions. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}1

Disease Associations

Obesity and Metabolic Syndrome

Human genetic studies have linked CIDEA variants to obesity and metabolic traits. The CIDEA gene is considered a candidate gene for obesity susceptibility, with certain polymorphisms associated with increased body mass index (BMI) and altered lipid profiles. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}2

Non-Alcoholic Fatty Liver Disease (NAFLD)

CIDEA dysregulation has been implicated in NAFLD, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). The protein’s role in hepatic lipid droplet formation and VLDL secretion influences the development and progression of fatty liver disease. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}3

Cancer

Alterations in CIDEA expression have been reported in various cancers. The protein can function as a tumor suppressor in some contexts, while in others it may support tumor progression. CIDEA affects cancer cell metabolism, proliferation, and survival through lipid metabolism and apoptosis regulation. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}4

Neurodegenerative Diseases (Hypothesized)

Based on the protein’s functions in lipid metabolism and autophagy, CIDEA may be relevant to:

• Alzheimer’s disease (altered lipid droplet dynamics)

• Parkinson’s disease (mitochondrial dysfunction, α-synuclein)

• Amyotrophic lateral sclerosis (TDP-43 pathology)

• Multiple system atrophy (lipid metabolism alterations)

Direct evidence establishing CIDEA as a driver or modifier of these conditions is limited and requires further investigation.

Key Research Findings

1. CIDEA was originally identified as a Fas-associated protein that modulates apoptosis. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}5

2. CIDEA is highly expressed in brown adipose tissue and promotes thermogenesis. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}6

3. Loss of CIDEA and CIDEB in mice causes hepatic steatosis and premature death. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}7

4. CIDEA regulates lipid droplet dynamics through dimerization and lipid interactions. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}8

5. Human CIDEA variants are associated with obesity and metabolic traits. ^{3Nod1, an Apaf-1-like activator of caspase-9 and nuclear factor-kappaB.1999 · J Biol Chem · DOI 10.1074/jbc.274.21.14560 · PMID 10329646Open reference}9

6. Lipid droplet accumulation is a hallmark of many neurodegenerative diseases. ^{4Cell death, dysglycemia and myocardial infarction.2013 · Biomed Rep · DOI 10.3892/br.2013.67 · PMID 24648945Open reference}0

7. CIDEA regulates autophagy through interactions with autophagy-related proteins. ^{4Cell death, dysglycemia and myocardial infarction.2013 · Biomed Rep · DOI 10.3892/br.2013.67 · PMID 24648945Open reference}1

8. CIDEA expression in glial cells may influence neuroinflammation. ^{4Cell death, dysglycemia and myocardial infarction.2013 · Biomed Rep · DOI 10.3892/br.2013.67 · PMID 24648945Open reference}2

Therapeutic Implications

Metabolic Disease

Given CIDEA’s central role in energy metabolism, the protein represents a potential therapeutic target for obesity and related metabolic disorders. Strategies to modulate CIDEA activity include:

• Small molecule activators to enhance thermogenesis

• Gene therapy approaches to increase CIDEA expression

• Targeting CIDEA interactions with other metabolic regulators

Neurodegeneration

Understanding CIDEA’s role in brain lipid metabolism could reveal new therapeutic approaches for neurodegenerative diseases:

• Modulating lipid droplet dynamics to protect neurons

• Enhancing autophagy to improve protein clearance

• Reducing oxidative stress through lipid metabolism regulation

• Targeting neuroinflammation through glial lipid metabolism

However, direct evidence for CIDEA-targeted therapies in neurodegeneration is currently limited and requires further research.

Related Proteins and Pathways

• CIDEB — CIDEA homolog in hepatic lipid metabolism

• Lipid droplets — Organelles regulated by CIDEA

• Autophagy — Cellular process modulated by CIDEA

• Brown adipose tissue — Primary site of CIDEA expression

• Metabolic syndrome — Disease context for CIDEA dysfunction

• Mitochondrial dysfunction — Related to CIDEA function

External Resources

• NCBI Gene: CIDEA

• Ensembl: ENSG00000108349

• UniProt: Q9Y281

• OMIM: 604440