Diabetes mellitus is a major metabolic disease characterized by chronic disturbances in glucose homeostasis.

Type 2 diabetes develops through interactions between insulin resistance, impaired pancreatic β-cell function, genetic factors, environmental influences, and metabolic stress.

Long-term diabetes can result in complications involving the kidneys, retina, nervous system, heart, and blood vessels.

Although protein-coding genes have traditionally received considerable attention in diabetes research, the human genome produces many RNA molecules that do not encode proteins.

These non-coding RNAs can regulate gene expression at transcriptional and post-transcriptional levels.

Increasing evidence indicates that dysregulated non-coding RNA expression contributes to several molecular pathways involved in diabetes.

Major Classes of Non-Coding RNAs

Non-coding RNAs can be classified according to their size, structure, and biological function.

Among these groups, microRNAs, long non-coding RNAs, and circular RNAs have received considerable attention in metabolic research.

MicroRNAs and Diabetes

MicroRNAs regulate gene expression by interacting with complementary sequences in target messenger RNAs.

A single microRNA can regulate multiple genes involved in related biological pathways.

Changes in microRNA expression can therefore influence insulin signaling, glucose transport, lipid metabolism, inflammation, and pancreatic β-cell function.

Some microRNAs have been associated with impaired insulin sensitivity and altered β-cell survival.

Their presence in circulating blood has also generated interest in their potential use as biomarkers.

Non-Coding RNAs and Insulin Resistance

Insulin resistance is a central component of type 2 diabetes.

Non-coding RNAs can influence signaling pathways involved in insulin receptor activity and glucose uptake.

Altered expression of specific microRNAs may affect components of the PI3K-AKT pathway and other metabolic signaling networks.

Long non-coding RNAs can also regulate transcription and interaction between regulatory proteins and RNA molecules.

Through these mechanisms, non-coding RNAs may influence glucose metabolism in skeletal muscle, liver, and adipose tissue.

Role in Pancreatic β-Cell Function

Pancreatic β-cells are responsible for producing and secreting insulin.

Their dysfunction is an important feature of diabetes progression.

Non-coding RNAs can regulate genes involved in β-cell differentiation, insulin synthesis, glucose sensing, and apoptosis.

Dysregulated RNA expression may therefore contribute to reduced insulin secretion and progressive β-cell dysfunction.

Understanding these mechanisms could help identify molecular targets for preserving β-cell function.

Non-Coding RNAs in Diabetic Complications

Long-term diabetes is associated with multiple complications.

Non-coding RNAs have been implicated in molecular processes underlying diabetic nephropathy, retinopathy, neuropathy, and cardiovascular disease.

Diabetic Nephropathy

Diabetic kidney disease involves glomerular injury, inflammation, oxidative stress, and fibrosis.

Several microRNAs and long non-coding RNAs have been investigated for their potential involvement in these pathways.

Non-coding RNAs may regulate transforming growth factor-beta signaling, extracellular matrix production, and inflammatory responses.

Because some RNA molecules can be detected in urine and blood, they may have potential as biomarkers of renal injury.

Diabetic Retinopathy

Diabetic retinopathy is characterized by progressive retinal vascular and cellular abnormalities.

Angiogenesis, inflammation, oxidative stress, and endothelial dysfunction contribute to disease progression.

Non-coding RNAs can influence vascular endothelial growth factor signaling and other pathways involved in retinal vascular changes.

Altered circulating or ocular microRNA profiles have therefore been investigated as potential indicators of retinal disease.

Long Non-Coding RNAs

Long non-coding RNAs are generally longer than 200 nucleotides and can regulate gene expression through diverse mechanisms.

They may interact with DNA, RNA, or proteins.

Some long non-coding RNAs can influence chromatin structure and transcription, whereas others regulate messenger RNA stability or translation.

In diabetes, altered long non-coding RNA expression has been associated with insulin resistance, inflammation, β-cell dysfunction, and diabetic complications.

Circular RNAs

Circular RNAs are formed through back-splicing events that generate covalently closed RNA structures.

Their circular configuration provides considerable stability.

Some circular RNAs can interact with microRNAs and influence the availability of these regulatory molecules.

Others may interact with proteins or regulate transcription.

Their stability in biological fluids makes circular RNAs attractive candidates for biomarker research.

This article was prepared as a concise narrative review of scientific literature concerning non-coding RNAs and diabetes.

Relevant studies addressing microRNAs, long non-coding RNAs, circular RNAs, insulin resistance, pancreatic β-cell dysfunction, diabetic nephropathy, retinopathy, neuropathy, and cardiovascular complications were considered.

The available evidence was synthesized to describe the major molecular mechanisms through which non-coding RNAs may influence diabetes and its complications.

Results

The reviewed evidence indicates that non-coding RNAs participate in multiple pathways associated with diabetes.

MicroRNAs can regulate genes involved in insulin signaling, glucose metabolism, inflammation, and β-cell function.

Long non-coding RNAs and circular RNAs can influence transcriptional regulation, RNA stability, protein interactions, and microRNA activity.

Altered non-coding RNA profiles have also been associated with several diabetic complications.

These findings support their potential use as molecular biomarkers and therapeutic targets.

Non-coding RNAs represent an important layer of gene regulation in diabetes.

Their ability to regulate multiple genes simultaneously makes them particularly relevant to complex metabolic diseases.

MicroRNAs can influence several components of insulin signaling and glucose metabolism.

Long non-coding RNAs may provide additional regulatory mechanisms through interactions with chromatin, proteins, and other RNA molecules.

Circular RNAs are especially interesting because their structural stability may allow them to persist in circulation.

The potential diagnostic value of non-coding RNAs is one of the most promising areas of research.

A circulating RNA profile may provide information about disease risk or tissue injury before conventional clinical manifestations become severe.

However, several challenges remain.

RNA expression can vary according to age, sex, metabolic status, medication use, tissue type, and sample-processing methods.

Therefore, large prospective studies and standardized laboratory methods are needed to establish clinically reliable biomarkers.

Non-coding RNAs may also represent therapeutic targets.

In principle, disease-associated RNAs could be inhibited using antisense approaches, RNA interference, or other RNA-based technologies.

Conversely, beneficial regulatory RNAs could potentially be restored.

However, effective and tissue-specific delivery remains an important challenge.

Therapeutic Perspectives

Future therapies may combine non-coding RNA modulation with conventional diabetes treatment.

Non-coding RNAs are important regulators of gene expression and contribute to several molecular mechanisms underlying diabetes and its complications.

MicroRNAs, long non-coding RNAs, and circular RNAs can influence insulin signaling, pancreatic β-cell function, inflammation, oxidative stress, fibrosis, and vascular injury.

Their presence in biological fluids also makes them promising candidates for early biomarkers.

Further research is needed to establish specific RNA signatures, clarify causal mechanisms, and develop safe methods for therapeutic RNA modulation.

The integration of non-coding RNA research with precision medicine may eventually improve early diagnosis, risk prediction, and individualized treatment of diabetes and its complications.

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