Epigenetics

Refers to the process whereby chromatin undergoes chemical modification in a response to the environment, and effects transcription.

Antigens sensitize lymphocytes to induce immunity and the specific senitiziation of monocytes, natural killer cells, and dendritic  cells are a result of epigenetic changes that enhance or suppress immune responses.

Immunologic stimuli of infections or immunizations have long-term consequences for the immune responsiveness of the individual.

Refers to information transmitted during cell division other than DNA sequence.

Epigenetic inheritance is defined as cellular information other than the DNA sequence itself, that is still heritable during cell division. 

DNA methylation and histone modifications comprise two of the main epigenetic modifications important for many physiological and pathological conditions, including cancer.

Methylating the cytosine within a gene can change its expression, a mechanism that is part of gene regulation that is called epigenetics. 

Aberrant DNA methylation is the most common molecular lesion in cancer-cells, even more frequent than gene mutations. 

Tumor suppressor gene silencing by CpG island promoter hypermethylation is supposed to be the most frequent epigenetic modification in cancer cells. 

Epigenetic characteristics of cells may be modified by several factors: environmental exposure, deficiencies of certain nutrients, and radiation.

It is suggested on a growing basis of evidence, that not only genetics but also epigenetics, contribute to aneuploid cell formation.

Cellular memory may promote chronic disease, such as atherosclerosis, with risk factors propagating maladaptive responses, including those inflammation end injury.

It provides information distinguishing cells, and organs from one another.

Epigenetics allows for biological memory.

Epigenetics begins with DNA and histone proteins, the two macromolecules structurally and functionally intertwined in chromatin.

DNA is tightly wound around spool-like histone proteins and transcription requires this complex to unwind and open into chromatin, allowing access to genes in their regulatory regions.

Epigenetics involves enzymes that place or remove histone marks and allows proteins to bind  to histone marks to facilitate assembly of transcriptional machinery.

The epigenome is susceptible to modification by the environment as well as to stochastic perturbations over time, adding phenotypic diversity in the population.

The above is demonstrated by lower life expectancy in boys whose grandfathers experienced famine prepubertally.

Applies to the modifications of DNA or associated proteins that carry information during cell division.

Alterations in gene expression that does not involve changes in DNA sequence.

Refers to stable changes in gene expression unrelated to changes in DNA structure.

Biochemical modification around chromatin, including DNA methylation and histone modifications.

Epic genic therapies seek to normalize DNA methylation patterns and post translational modifications on histones that promote or maintain a malignant phenotype.

May be deregulated in various disease, including cancer.

Epigenetics include DNA methylation, posttransitional modifications of nucleosome proteins, and nucleosome density,

For most common illnesses, both genetic predisposition and environmental influences shape risk which increases with age.

Epigenomics refers to the study of epigenetic marks on the genome or near-genome scale.

Epigenomes capture the biological influence of environment and lifestyle factors in a quantifiable and analyzable molecular form.

Epigenetic dysregulation is a hallmark of several complex pathologies including: hypertension, other cardiovascular disease risk factors such as smoking, diabetes, and aging, cardiovascular disease and all-cause mortality.

Epigenetic modifications may influence protein changes of genes and can be transmitted through mitosis or meiosis without altering DNA sequence.

Enzymes that regulate methylation of cytosines on DNA plus post-translational histone modifications, afe the machinery that regulate DNA replication and repair and RNA transcription.

Epigenetic mechanisms play a role in the pathophysiology of addiction.

 

Some alterations to the epigenome which arise through chronic exposure to addictive stimuli during an addiction can be transmitted across generations.

 

Epigenome alterations affect  the behavior of one’s children: the child’s behavioral responses to addictive drugs and natural rewards.

 

Epigenetic alterations implicated in transgenerational epigenetic inheritance include DNA methylation, histone modifications, and downregulation or upregulation of microRNAs.