Biology subjects

Pham, L. K.

Publications and source records attributed to Pham, L. K..

3 recordsLinked to original sources

bioRxiv2025

NRF2 inhibition of alveolar macrophage MHC II expression during Mycobacterium tuberculosis infection

During Mycobacterium tuberculosis (Mtb) infection, infected alveolar macrophages (AMs) initially up-regulate a NRF2 regulated cell-protective program, which is detrimental to host control and impedes AM activation, including MHC II expression. MHC II is critical for CD4+ T cell activation and host immunity during Mtb infection. We hypothesized that NRF2 regulates the MHC II pathway and AM antigen presentation to T cells. We found that NRF2 inhibits MHC II, but not MHC I, specifically in AMs, following Mtb infection in vitro and in vivo. NRF2 dampens Ciita and H2-Ab1 gene expression in uninfected AMs, and MHC II inhibition by NRF2 is retained following innate stimuli and IFN{gamma} exposure. NRF2 expression in Mtb-infected AMs impedes their ability to activate ESAT6-specific CD4+ T cells. Thus, although NRF2 expression enhances cell-protective functions, it has the unexpected consequence of limiting innate-adaptive crosstalk, which can impair CD4+ T cell activation and host immunity during Mtb infection. HIGHLIGHTSO_LINRF2 inhibits MHC II on AMs, but not DCs, MDMs, or PMNs, during Mtb infection C_LIO_LINRF2 inhibits Ciita and H2-Ab1 and total MHC II protein in AMs, but not in BMDMs C_LIO_LINRF2 blockade of AM MHC II is retained following PAMP and IFN{gamma} stimulation C_LIO_LINRF2 impedes the activation of antigen-specific CD4+ T cells by Ams C_LI

immunology↗

bioRxiv2024

Absence of c-Maf and IL-10 enables Type I IFN enhancement of innate responses to low-dose LPS in alveolar macrophages

Alveolar macrophages (AMs) are lower-airway resident myeloid cells and are among the first to respond to inhaled pathogens. Here, we interrogate AM innate sensing to Pathogen Associated Molecular Patterns (PAMPs) and determine AMs have decreased responses to low- dose LPS compared to other macrophages, as measured by TNF, IL-6, Ifnb, and Ifit3. We find the reduced response to low-dose LPS correlates with minimal TLR4 and CD14 surface expression, despite sufficient internal expression of TLR4. Additionally, we find that AMs do not produce IL-10 in response to a variety of PAMPs due to low expression of transcription factor c- Maf and that lack of IL-10 production contributes to an enhancement of pro-inflammatory responses by Type I IFN. Our findings demonstrate that AMs have cell-intrinsic dampened responses to LPS, which is enhanced by type I IFN exposure. These data implicate conditions where AMs may have reduced or enhanced sentinel responses to bacterial infections. HIGHLIGHTSO_LIAlveolar macrophages (AMs) do not produce TNF or IL-6 in response to low-dose LPS due to minimal surface expression of TLR4 and CD14 C_LIO_LILack of AM IL-10 production is dependent on low c-Maf expression C_LIO_LIExogenous c-Maf expression increases AM IL-10 production C_LIO_LIIFN{beta} enhances AM TNF and IL-6 responses to low-dose LPS and this is dependent on a lack of IL-10 C_LI

immunology↗

bioRxiv2022

Identification of potential inhibitors of cutaneous Melanoma and Non-Melanoma skin cancer cells through in vitro and in silico screening of a small library of Phenolic compounds

Melanoma and non-melanoma skin cancers are the most-lethal and commonest forms of skin cancers, that affecting one-fifth of the US population. With the aim of identifying new lead compounds as starting point for attaining cost-effective therapies, a small library of about 90 molecules was screened in vitro against A375, SKMEL-28, A431, SCC-12 skin cancer cell lines. About 35 of them, mainly dihydroquinolines, C-C and C-N linked biphenyls, and substituted methylgallate or aniline derivatives, displayed low-micromolar range activities, primarily against the A431 and SCC-12 squamous carcinoma cell lines, with only a handful of these compounds displaying any activity against the A375 and SKMEL-28 melanoma cell lines. Compounds 11 (A431: IC50 = 5.0 {micro}M, SCC-12: IC50 = 2.9 {micro}M, SKMEL-28: IC50 = 4.9 {micro}M, A375: IC50 = 6.7 {micro}M) and 13 (A431: IC50 = 5.0 {micro}M, SCC-12: IC50 = 3.3 {micro}M, SKMEL-28: IC50 = 13.8 {micro}M, A375: IC50 = 17.1 {micro}M) were the most active across all these cell lines. Furthermore, many of the hit compounds showed little to no activity against mammalian nontumorigenic immortalized HaCaT cells, with a far better selectivity index than cisplatin (a well-known anticancer agent used as a positive control). Compounds 11 and 13 significantly and dose-dependently induced apoptosis of SCC-12 and SK-MEL-28 cells as evidenced by the downregulation of Bcl-2 and upregulation of Bax protein expression levels, and by cleaved caspase-3, caspase-9 and PARP levels. Both agents also significantly reduced scratch wound healing, colony formation, and activated expression levels of major cancer molecular targets such as RSK/AKT/ERK1/2 and S6K1. To provide a better attribute profile for each of the hit molecules, in-silico target(s) prediction, pharmacokinetic and ADMET studies are also reported, together with some preliminary structure-activity relationship outlines. The SwissTargetPrediction web-based tool identified CDK8, CLK4, nuclear receptor ROR, tyrosine protein-kinase Fyn/LCK, ROCK1/2, and PARP, all of which are dysregulated in skin cancers, as likely targets for these hit compounds. Furthermore, the SwissADME web_tool predicted these compounds to exhibit high GI tract absorption, good skin permeation, and a viable biodegradability profile. To summarize, these data highlight the promising anticancer potential of these small molecules leads, warranting further investigation and/or optimization towards obtaining clinical candidates for combatting both melanoma and non-melanoma skin cancers.

pharmacology and toxicology↗