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Microbes & Immunity Big data and DNN-based DTI model in CHP

complex. Both protein TRADD and protein RIPK1 are In summary, the TNF signaling pathway has a crucial
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major participants in TNFR1 signaling, contributing to effect on target genes like BCL2, BCLXL, GSK3A/B, and
NF-κB activation and cell death signaling pathways. 51 NFKB through the PI3K/AKT signal pathway. In addition,
The importance of TRADD in regulating TNF- the TNF signaling pathway is a multifaceted regulator of
induced cell signaling is cell type-dependent and diverse cellular processes with far-reaching implications in
may be related to the amount of RIPK1 present in the various physiological and pathological contexts, including
corresponding cell type. TRADD and RIPK1 are also inflammation and immunity in CHP.
considered to have redundant or competitive activities 3.3. The role of cell cycle control signaling pathways
in certain contexts. In addition to its role in regulating in the pathogenesis of CHP
cell survival and death, the TNF signaling pathway also
influences immune cell differentiation and function. 3.3.1. The role of C-X-C motif chemokine ligand 1-C-
For instance, TNF-α suppresses the differentiation of X-C motif chemokine receptor 2 chemokines signaling
induced regulatory T cells (iTregs) through a signaling axis in the pathogenesis of CHP
cascade involving the induction of TNF-R2 expression C-X-C motif chemokine receptor 2 is the chemokine
and the activation of AKT. Activated AKT interacts receptor for CXCL1, which has been shown to inhibit
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with SMAD, leading to the inhibition of TGF-β-induced fibrosis progression and reduce macrophage recruitment
SMAD3 phosphorylation, which is essential for iTreg in the pneumonitis microenvironment, providing insights
differentiation. When AKT phosphorylates TF FOXO, into potential therapeutic strategies for treating CHP
it causes the sequestration of FOXO, preventing TF patients with high CXCL1 expression. Certain organic
FOXO from entering the nucleus and transcribing target microbes, particularly bacteria and fungi, interact with
genes. This leads to the inhibition of TF FOXO’s roles CXCR1 and CXCR2 chemokine receptors by promoting
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in apoptosis, cell cycle regulation, and oxidative stress IL-8 production and neutrophil recruitment. This
resistance. Simultaneously, AKT phosphorylates TF interaction plays a crucial role in the pathogenesis of
BCL2 associated agonist of cell death (BAD) at specific CHP, driving the persistent inflammatory response that
serine residues. This binding sequesters BAD in the leads to lung damage. This chemo synapse comprises
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cytosol, preventing target genes BCL2 and BCLXL, multiple proteins that can interact with CXCR2 in both
which play critical roles in regulating cell survival by its activated and inactivated conformational states, with
inhibiting the apoptotic pathways. This inhibits the some interactions being modulated on receptor activation.
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intrinsic apoptosis pathway, preventing Caspase-9 Sodium hydrogen exchanger regulatory factor-1 adaptor
(Casp9) activation and promoting cell survival. protein contains a PDZ motif that facilitates its binding
Conversely, when AKT activity is low, TFs FOXO and to both CXCR2 and phospholipase C-β (PLC-β). This
BAD can promote apoptosis through mitochondrial interaction is critical for CXCR2-mediated activation of
pathways involving Casp9. The activity of the target gene PLC-β and subsequent downstream signaling cascades.
GSK3A/B is regulated by upstream signals, particularly On CXCR2 activation, protein kinase C delta (PKC-δ)
the PI3K/AKT signal pathway. When AKT is activated, phosphorylates vasodilator-stimulated phosphoprotein
it phosphorylates and inhibits GSK3A/B, which (VASP), enabling its binding to the receptor. The
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subsequently promotes cell survival by reducing their phospholipase C-diacylglycerol (DAG)-PKC signaling
pro-apoptotic activity. On the other hand, the activation axis is crucial for translating extracellular signals into
of AKT stimulates the expression of gene IL8, which appropriate cellular responses, allowing cells to adapt
leads to protein synthesis activation. Furthermore, TNF to their environment and maintain homeostasis. DAG
signaling intersects with other core signaling pathways, recruits PKC isoforms to the plasma membrane. The
such as the PI3K/AKT and NF-κB pathways. PI3K phosphorylated VASP then associates with filamentous
and AKT stimulate gene NFKB activation in a dose- actin (F-actin), thereby linking the chemo synapse to
dependent manner, suggesting a common link between the actin cytoskeleton, a process vital for chemotactic
these pathways. TNF-R1, NF-κB inducing kinase, and responses. In addition, PKC can act upstream of p38
inhibitory-κB kinase partially participate in AKT- MAPK. For instance, certain stress and inflammatory
induced NF-κB stimulation, and PI3K-AKT signaling signals that activate PKC can also lead to the activation
can activate NF-κB through both TNFR-dependent and of p38 MAPK. This can occur through the activation of
independent mechanisms. This interplay between the upstream kinases that phosphorylate and activate p38, so
TNF, PI3K/AKT, and NF-κB pathways may represent CXCR2 activation triggers the ERK p38-MAPK pathway
a mechanism by which AKT exerts its anti-apoptotic through multiple mechanisms, contributing to various
function and cell proliferation in fibrosis cells. cellular processes. Subsequently, MKK4 activation
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Volume 2 Issue 2 (2025) 95 doi: 10.36922/mi.4620