By Lila Rouland | Published on august 20, 2025 | 3 min read
#DeNovoLipogenesis
#WhiteAdiposeTissue #Obesity #Type2Diabetes #LipidMetabolism
This study
explores the role of CDK6 (Cyclin-dependent kinase 6) in regulating de
novo lipogenesis (DNL)—the synthesis of fatty acids from non-lipid
precursors. DNL in white adipose tissue (WAT) is linked to improved
insulin sensitivity, whereas its activation in the liver promotes insulin
resistance, fatty liver (steatosis), and other metabolic disorders. The goal
was to determine whether targeted inhibition of CDK6 could enhance
beneficial DNL in adipose tissue without worsening hepatic side effects.
Turning
off CDK6 activates lipogenesis… but only in fat tissue
In
genetically modified mice carrying an inactive CDK6 allele (K43M), researchers
observed a strong increase in DNL in visceral adipose tissue (VAT), but no
effect in the liver. This lipogenic induction was associated with
upregulation of CHREBP (Carbohydrate-Responsive Element-Binding Protein)
and key enzymes: ACLY, ACC1, FASN, and SCD1.
Treatment
with LEE011 (ribociclib), a pharmacological CDK6/CDK4 inhibitor,
reproduced these effects in wild-type mice fed a high-fat diet (HFD). Results
included reduced
fat mass, increased browning of
subcutaneous adipose tissue, enhanced DNL in adipose tissue, and no induction of hepatic
lipogenesis.
AMPKα & CHREBPβ: the key targets of CDK6 in controlling
DNL
Mechanistically,
CDK6 directly phosphorylates AMPKα and CHREBPβ:
- Phosphorylation of AMPKα at Thr-172 activates it, leading to inhibitory phosphorylation of acetyl-CoA carboxylase (ACC1), thereby blocking lipogenesis.
- CHREBPβphosphorylation by CDK6 prevents its nuclear entr y and
subsequent activation of lipogenic genes.
In K43M
mice, loss of CDK6 kinase activity reduced phosphorylation of both proteins,
promoting nuclear accumulation of CHREBPβ and massive induction of lipogenic enzymes in
adipose tissue.
RUNX1: the
key transcriptional relay of CDK6
The study
also shows that RUNX1, a well-known transcription factor in hematology,
acts as a critical mediator of CDK6 in adipocytes. In K43M mice with adipocyte-specific
deletion of RUNX1 (KR mice), the increase in DNL and CHREBPβ was completely abolished in VAT.
This demonstrates an adipose-specific transcriptional regulation that
does not occur in the liver.
In
adipose-derived stem cells (ADSCs) from K43M mice, shRNA knockdown of CHREBP
significantly reduced SCD1 expression but not other lipogenic enzymes,
suggesting a cooperative regulation by CHREBP, RUNX1, and possibly SREBP-1c
or MondoA.
CDK6 targets
fat, not the liver
While DNL
was amplified in VAT, the liver was unaffected—or even showed a slight decrease
in certain lipogenic enzymes under inactive CDK6. The study highlights organ-specific
signaling differences. In adipose tissue, CDK6
inhibition suppressed mTOR/AMPK signaling. In the liver, these pathways
were activated.
This
signaling divergence likely explains the tissue-specific effect of CDK6
on DNL.
Clinical
perspectives: toward new metabolic therapies
The
findings suggest that targeted CDK6 inhibition could:
- Stimulate
beneficial adipose DNL,
- Improve glucose tolerance and
insulin sensitivity,
- Reduce obesity-related
inflammatory complications,
- Avoid hepatic side effects such
as steatosis.
CDK6
inhibitors like ribociclib, already approved in oncology, represent promising
candidates for repurposing in the treatment of type 2 diabetes and
metabolic disorders.
Read next: Reprogramming fat to starve the tumor?
About the Author – Lila Rouland
Doctor of Oncology, specialized in Biotechnology and Management
With dual expertise in science and marketing, Lila brings her knowledge to the service of healthcare innovation. After five years in international academic research, she transitioned into medical and scientific communication within the pharmaceutical industry. Now working as a medical writer and content developer, she is committed to highlighting scientific knowledge and conveying it to healthcare professionals with clarity and relevance.
