Inhibition of Rb phosphorylation leads to H(2)S-mediated inhibition of NF-kB in acute pancreatitis and associated lung injury in mice

Drug repurposing of cyclin-dependent kinase inhibitors for neutrophilic acute respiratory distress syndrome and psoriasis

BACKGROUND

Neutrophilic inflammation, characterized by dysregulated neutrophil activation, triggers a variety of inflammatory responses such as chemotactic infiltration, oxidative bursts, degranulation, neutrophil extracellular traps (NETs) formation, and delayed turnover. This type of inflammation is pivotal in the pathogenesis of acute respiratory distress syndrome (ARDS) and psoriasis. Despite current treatments, managing neutrophil-associated inflammatory symptoms remains a significant challenge.

AIM OF REVIEW

This review emphasizes the role of cyclin-dependent kinases (CDKs) in neutrophil activation and inflammation. It aims to highlight the therapeutic potential of repurposing CDK inhibitors to manage neutrophilic inflammation, particularly in ARDS and psoriasis. Additionally, it discusses the necessary precautions for the clinical application of these inhibitors due to potential off-target effects and the need for dose optimization.

KEY SCIENTIFIC CONCEPTS OF REVIEW

CDKs regulate key neutrophilic functions, including chemotactic responses, degranulation, NET formation, and apoptosis. Repurposing CDK inhibitors, originally developed for cancer treatment, shows promise in controlling neutrophilic inflammation. Clinical anticancer drugs, palbociclib and ribociclib, have demonstrated efficacy in treating neutrophilic ARDS and psoriasis by targeting off-label pathways, phosphoinositide 3-kinase (PI3K) and phosphodiesterase 4 (PDE4), respectively. While CDK inhibitors offer promising therapeutic benefits, their clinical repurposing requires careful consideration of off-target effects and dose optimization. Further exploration and clinical trials are necessary to ensure their safety and efficacy in treating inflammatory conditions.

Vitamin B6 ameliorates acute pancreatitis by suppressing the caspase3 signaling pathway

BACKGROUND

Acute pancreatitis (AP) is a prevalent exocrine inflammatory disorder of the pancreas characterized by pancreatic inflammation and injury to acinar cells. Vitamin B6 (VB6) is a vital nutrient that plays a significant role in preserving human health and has anti-inflammatory and anti-apoptotic effects.

METHODS

This study aimed to explore the potential pancreatic protective effects of VB6 in mitigating pancreatic inflammation and apoptosis induced by taurocholate sodium (TLCS) in an AP model and to assess the underlying mechanism of action. AP was induced in Sprague‒Dawley (SD) rats through TLCS administration and lipopolysaccharide (LPS)-treated AR42J cells, followed by treatment with VB6.

RESULTS

Various parameters associated with AP were assessed in both plasma and pancreatic tissues. VB6 has been shown to ameliorate the severity of AP through various mechanisms. It effectively reduces the levels of serum amylase, lipase, and inflammatory factors, thereby mitigating histological injury to the pancreas. Moreover, VB6 inhibited pancreatic apoptosis by downregulating bax expression and up-regulating Bcl2 expression in TLCS-treated rats. Additionally, VB6 suppressed the expression of caspase3. The anti-inflammatory and anti-apoptotic effects of VB6 observed in LPS-treated AR42J cells are consistent with those observed in a rat model of AP.

CONCLUSIONS

These results suggest that VB6 exerts anti-inflammatory and anti-apoptotic effects through inhibition of the caspase3 signaling pathway and has a protective effect against AP.

A non-human primate derived anti-P-selectin glycoprotein ligand-1 antibody curtails acute pancreatitis by alleviating the inflammatory responses

Acute pancreatitis (AP) is a devastating disease characterized by an inflammatory disorder of the pancreas. P-selectin glycoprotein ligand-1 (PSGL-1) plays a crucial role in the initial steps of the adhesive at process to inflammatory sites, blockade of PSGL-1 might confer potent anti-inflammatory effects. In this study, we generated two non-human primate derived monoclonal antibodies capable of efficiently targeting human PSGL-1, RH001-6 and RH001-22, which were screened from immunized rhesus macaques. We found that RH001-6, can effectively block the binding of P-selectin to PSGL-1, and abolish the adhesion of leukocytes to endothelial cells in vitro. In vivo, we verified that RH001-6 relieved inflammatory responses and pancreatic injury in both caerulein and l-arginine induced AP models. We also evaluated the safety profile after RH001-6 treatment in mice, and verified that RH001-6 did not cause any significant pathological damages in vivo. Taken together, we developed a novel non-human primate derived PSGL-1 blocking antibody with high-specificity, named RH001-6, which can interrupt the binding of PSGL-1 and P-selectin and attenuate inflammatory responses during AP. Therefore, RH001-6 is highly potential to be further developed into therapeutics against acute inflammatory diseases, such as AP.

Inhibition of CDK4/6 regulates AD pathology, neuroinflammation and cognitive function through DYRK1A/STAT3 signaling

Repurposing approved drugs is an emerging therapeutic development strategy for Alzheimer's disease (AD). The CDK4/6 inhibitor abemaciclib mesylate is an FDA-approved drug for breast cancer treatment. However, whether abemaciclib mesylate affects Aβ/tau pathology, neuroinflammation, and Aβ/LPS-mediated cognitive impairment is unknown. In this study, we investigated the effects of abemaciclib mesylate on cognitive function and Aβ/tau pathology and found that abemaciclib mesylate improved spatial and recognition memory by regulating the dendritic spine number and neuroinflammatory responses in 5xFAD mice, an Aβ-overexpressing model of AD. Abemaciclib mesylate also inhibited Aβ accumulation by enhancing the activity and protein levels of the Aβ-degrading enzyme neprilysin and the α-secretase ADAM17 and decreasing the protein level of the γ-secretase PS-1 in young and aged 5xFAD mice. Importantly, abemaciclib mesylate suppressed tau phosphorylation in 5xFAD mice and tau-overexpressing PS19 mice by reducing DYRK1A and/or p-GSK3β levels. In wild-type (WT) mice injected with lipopolysaccharide (LPS), abemaciclib mesylate rescued spatial and recognition memory and restored dendritic spine number. In addition, abemaciclib mesylate downregulated LPS-induced microglial/astrocytic activation and proinflammatory cytokine levels in WT mice. In BV2 microglial cells and primary astrocytes, abemaciclib mesylate suppressed LPS-mediated proinflammatory cytokine levels by downregulating AKT/STAT3 signaling. Taken together, our results support repurposing the anticancer drug, CDK4/6 inhibitor abemaciclib mesylate as a multitarget therapeutic for AD pathologies.

H2S contributed from CSE during cellular senescence suppresses inflammation and nitrosative stress

Aging involves the time-dependent deterioration of physiological functions attributed to various intracellular and extracellular factors. Cellular senescence is akin to aging and involves alteration in redox homeostasis. This is primarily marked by increased reactive oxygen/nitrogen species (ROS/RNS), inflammatory gene expression, and senescence-associated beta-galactosidase activity, all hallmarks of aging. It is proposed that gasotransmitters which include hydrogen sulfide (H₂S), carbon monoxide (CO), and nitric oxide (NO), may affect redox homeostasis during senescence. H₂S has been independently shown to induce DNA damage and suppress oxidative stress. While an increase in NO levels during aging is well established, the role of H₂S has remained controversial. To understand the role of H₂S during aging, we evaluated H₂S homeostasis in non-senescent and senescent cells, using a combination of direct measurements with a fluorescent reporter dye (WSP-5) and protein sulfhydration analysis. The free intracellular H₂S and total protein sulfhydration levels are high during senescence, concomitant to cystathionine gamma-lyase (CSE) expression induction. Using lentiviral shRNA-mediated expression knockdown, we identified that H₂S contributed by CSE alters global gene expression, which regulates key inflammatory processes during cellular senescence. We propose that H₂S decreases inflammation during cellular senescence by reducing phosphorylation of IκBα and the p65 subunit of nuclear factor kappa B (NF-κB). H₂S was also found to reduce NO levels, a significant source of nitrosative stress during cellular senescence. Overall, we establish H₂S as a key gasotransmitter molecule that regulates inflammatory phenotype and nitrosative stress during cellular senescence.

Clinical features of CDK4/6 inhibitor-related interstitial lung disease in patients with breast cancer: a case series study

BACKGROUND

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are the standard treatment for advanced hormone receptor-positive breast cancer. Although interstitial lung disease is a rare (1-3.3%) but serious adverse event associated with CDK4/6 inhibitors, the incidence of interstitial lung disease in Japanese patients in the real world and the risk factors of interstitial lung disease are not clear.

METHODS

We retrospectively investigated the incidence of interstitial lung disease in 224 patients with advanced breast cancer who received CDK4/6 inhibitors at our hospital between 31 January 2017 and 31 January 2021. The correlation of age (>50 vs ≤50 years), presence or absence of previous history of interstitial lung disease, lung metastasis, smoking history and chest radiation with the development of interstitial lung disease was evaluated.

RESULTS

In total, 177 cases received palbociclib, 39 cases received abemaciclib and 8 cases received both palbociclib and abemaciclib, constituting a palbociclib group (n = 185) and an abemaciclib group (n = 47). At a median observation period of 607 days, 8.0% (18/224) cases (13 definite and 5 probable cases) had interstitial lung disease; 6.5% (12/185) of palbociclib-treated and 13% (6/47) of abemaciclib-treated cases. The median time to interstitial lung disease onset was 178 (range, 14-750) days. There was no significant correlation between the background factors studied and the development of interstitial lung disease.

CONCLUSION

The frequency of CDK4/6 inhibitor-induced interstitial lung disease was higher than that reported in clinical trials. We did not identify any risk factors for the development of interstitial lung disease in this study, and thus, larger studies that include patient predisposition are required.

Applications and mechanisms of the cyclin-dependent kinase 4/6 inhibitor, PD-0332991, in solid tumors

Abnormal CDK4/6-Rb-E2F signal transduction is a common finding in tumors and is a driving factor for the excessive proliferation of various tumor cells. PD-0332991, a highly specific, small molecule inhibitor for CDK4 and 6, has been shown to inhibit tumor growth by abrogating the phosphorylating capacity of CDK4/6 and suppressing Rb phosphorylation. It has been promoted for the treatment of breast cancer and potentially for other tumor types such as liver cancers, lung cancers and sarcomas. Due to the risk of monotherapy resistance, PD-0332991 is commonly used in combination with other drugs. Such combination treatments have proved able to inhibit tumor proliferation more effectively, induce stronger senescence and apoptosis, and enhance the efficiency of immunotherapy. Therefore, tumor cells with senescence induced by PD-0332991 are now used as ideal screening tools of cytolytic drugs with more efficient and thorough anti-tumor properties. With more extensive understandings about the branching points between senescence and apoptosis, it is possible to refine the dosage of PD-0332991. Better characterization of resistant cells, of inhibitors and of adverse effects such as leukopenia are needed to overcome obstacles in the use of PD-0332991. In this review of PD-0332991 research, we hope to provide guidance of transitions from laboratory findings to clinical applications of PD-0332991 and to facilitate PD-0332991-based multi-inhibitor combination therapies for various tumors.

The effect of γ-linolenic acid on Polycystic Ovary Syndrome associated Focal Segmental Glomerulosclerosis via TGF-β pathway

BACKGROUND

In recent years, female infertility from Polycystic Ovary Syndrome (PCOS) has gained scientific interest. PCOS alters the metabolic and endocrine functioning in females. The elevation in androgens can damage the androgen receptors present on the kidney giving rise to renal disorders like Focal Segmental Glomerulosclerosis (FSGS). Transforming Growth Factor Beta (TGF-β) in the ovary is activated by activin for Follicle Stimulating Hormone (FSH) secretion and in the kidney by thrombospondin 1 (TSP1) for cell growth and apoptosis. Studies show that gamma-linolenic acid (GLA) effectively treats breast cancer, eczema, inflammatory conditions and PCOS.

AIM

The study aimed to find out the possibility of FSGS development in PCOS and to understand the effect of GLA on FSGS via the TGF-β pathway.

METHOD

To carry out the study, the dehydroepiandrosterone (DHEA) induced PCOS model was used. Three groups namely vehicle control, DHEA, and DHEA+GLA, were used with six animals in each. TGF-β1, TGF-β2, and TSP1 genes were studied using real-time PCR.

RESULTS

The study showed an increase in the level of renal fibrosis biomarker, TSP1, in the DHEA group, which was further decreased by an anti-inflammatory agent, GLA. The TGF-β1 and TGF-β2 genes associated with the TGF-β pathway were seen to be increased in DHEA-induced PCOS rats which showed a possible relation between the two conditions.

CONCLUSION

The study shows a possible development of renal fibrosis in the DHEA-induced PCOS model. The GLA might act as a ligand to regulate TGF-β signaling in glomerulosclerosis in a DHEA-induced PCOS model.

Role of Hydrogen Sulfide in the Endocrine System

Hydrogen sulfide (H₂S), as one of the three known gaseous signal transduction molecules in organisms, has attracted a surging amount of attention. H₂S is involved in a variety of physiological and pathological processes in the body, such as dilating blood vessels (regulating blood pressure), protecting tissue from ischemia-reperfusion injury, anti-inflammation, carcinogenesis, or inhibition of cancer, as well as acting on the hypothalamus and pancreas to regulate hormonal metabolism. The change of H₂S concentration is related to a variety of endocrine disorders, and the change of hormone concentration also affects the synthesis of H₂S. Understanding the effect of biosynthesis and the concentration of H₂S on the endocrine system is useful to develop drugs for the treatment of hypertension, diabetes, and other diseases.