Ten Crucial Signaling Pathways in Human Health and Disease: From Cellular Regulation to Drug Targets

Signaling Pathways in Human Health and Disease: Signaling Pathways are fundamental to cellular communication, regulating vital processes such as growth, immune response, metabolism, differentiation, and apoptosis. This review highlights ten major pathways that have gained significant attention in modern biomedical research and drug development: PI3K/AKT/mTOR, MAPK/ERK, NF-κB, Wnt/β-catenin, JAK/STAT, TGF-β/Smad, Notch, Hippo/YAP, AMPK, and cGAS-STING. These pathways are deeply involved in diseases such as cancer, autoimmune disorders, metabolic syndromes, and fibrosis. A deeper understanding of these mechanisms provides crucial insights into disease pathogenesis and supports the development of targeted therapies and precision medicine approaches across diverse medical fields.

---

In modern biomedical research, signaling pathways are crucial networks through which cells communicate with their environment and regulate their own functions. Through these pathways, cells sense external stimuli and regulate growth, immune responses, metabolic states, and death or differentiation. Below, we review ten signaling pathways that have garnered the most attention in scientific research and drug development.

1. PI3K/AKT/mTOR Pathway

The PI3K/AKT/mTOR pathway is a core pathway regulating cell growth, proliferation, metabolism, and survival. When PI3K is activated, it activates AKT, which in turn regulates mTOR activity, promoting protein synthesis and energy metabolism. This pathway is crucial in the study of tumorigenesis, diabetes, and aging, and is a target for many anticancer drugs.

PI3K/AKT/mTOR signaling pathway

2. MAPK/ERK Pathway

The MAPK/ERK pathway is involved in regulating cell proliferation, differentiation, and apoptosis. When growth factors or stress signals act on cell surface receptors, the MAPK cascade is triggered, ultimately activating ERK and regulating gene expression. This pathway is closely associated with various tumors and inflammatory diseases.

Mechanism of action of the MAPK/ERK pathway

3. NF-κB Pathway

NF-κB is the “switch” for inflammatory and immune responses. Upon infection, oxidative stress, or inflammatory stimulation, NF-κB becomes activated and enters the cell nucleus, initiating the expression of inflammation-related genes. Abnormal activation can lead to chronic inflammation, tumors, and autoimmune diseases.

Activation of canonical and non-canonical NF-κB pathways

4. Wnt/β-catenin Pathway

Wnt signaling controls gene expression by regulating the accumulation of β-catenin in the cell nucleus. This pathway plays a crucial role in embryonic development, stem cell maintenance, and tissue regeneration. Aberrant activation is closely linked to the maintenance of cancer stem cells and cancer progression.

Wnt signaling mechanism

5. JAK/STAT pathway

The JAK/STAT pathway is a core pathway in cytokine signaling. Cytokine binding to receptors activates JAKs, which then phosphorylate STATs. STATs then enter the cell nucleus and regulate the expression of genes related to immunity and inflammation. This pathway is of particular interest in rheumatic diseases, hematologic disorders, and antiviral immunity.

JAK-STAT signaling

6. TGF-β/Smad Pathway

TGF-β signaling, mediated by Smad proteins, regulates cell proliferation, differentiation, immunosuppression, and fibrosis. Excessive activation can lead to organ fibrosis or cancer immune escape. Therefore, this pathway is an important target for anti-fibrotic and tumor therapy research.

TGF-β/SMAD signaling pathway

7. Notch Pathway

Notch signaling plays a key role in cell fate determination, stem cell maintenance, and tissue development. Upon receptor-ligand binding, Notch receptors are cleaved, releasing intracellular fragments that enter the nucleus and regulate genes. This pathway is widely used in oncology, angiogenesis, and regenerative medicine.

Notch signaling pathway

8. Hippo/YAP Pathway

Hippo signaling regulates organ size and cell proliferation. Its core regulatory proteins, YAP/TAZ, determine whether cells grow or undergo apoptosis. When the Hippo pathway is inactivated, YAP enters the cell nucleus, promoting proliferation and resisting apoptosis. This pathway is highly sought after in cancer and tissue regeneration research.

The core Hippo pathway in mammals

9. AMPK Pathway

AMPK is a sensor of cellular energy status. It is activated when energy is insufficient, promoting energy production and inhibiting energy expenditure. This pathway has attracted considerable attention in the study of diabetes, obesity, and metabolic syndrome, and is also a key target for metabolic intervention drugs.

AMPK signaling pathway

10. cGAS-STING Pathway

cGAS-STING is an intracellular DNA sensing system that activates antiviral and anti-tumor immune responses by recognizing abnormal DNA. This pathway is gaining increasing attention in immunotherapy, vaccine development, and inflammation research.

cGAS–STING signal transduction mechanism

These hot signaling pathways cover core research areas such as oncology, immunity, metabolism, fibrosis, and regenerative medicine. A deeper understanding of their regulatory mechanisms will not only help reveal the mechanisms of disease occurrence, but also provide a theoretical basis for the development of targeted drugs.