Xiaolei Tang

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder in the intestines without a cure. Current therapies suppress inflammation to prevent further intestinal damage. However, healing already damaged intestinal epithelia is still an unmet medical need. Under physiological conditions, Lgr5⁺ intestinal stem cells (ISCs) in the intestinal crypts replenish the epithelia every 3–5 days. Therefore, understanding the regulation of Lgr5⁺ ISCs is essential. Previous data suggest vitamin D signaling is essential to maintain normal Lgr5⁺ ISC function in vivo. Our recent data indicate that to execute its functions in the intestines optimally, 1,25(OH)₂D requires high concentrations that, if present systemically, can cause hypercalcemia (i.e., blood calcium levels significantly higher than physiological levels), leading to severe consequences. Using 5-bromo-2′-deoxyuridine (BrdU) to label the actively proliferating ISCs, our previous data suggested that de novo synthesized locally high 1,25(OH)₂D concentrations effectively enhanced the migration and differentiation of ISCs without causing hypercalcemia. However, although sparse in the crypts, other proliferating cells other than Lgr5⁺ ISCs could also be labeled with BrdU. This current study used high-purity Lgr5⁺ ISC lines and a mouse strain, in which Lgr5⁺ ISCs and their progeny could be specifically tracked, to investigate the effects of de novo synthesized locally high 1,25(OH)₂D concentrations on Lgr5⁺ ISC function. Our data showed that 1,25(OH)₂D at concentrations significantly higher than physiological levels augmented Lgr5⁺ ISC differentiation in vitro. In vivo, de novo synthesized locally high 1,25(OH)₂D concentrations significantly elevated local 1α-hydroxylase expression, robustly suppressed experimental colitis, and promoted Lgr5⁺ ISC differentiation. For the first time, this study definitively demonstrated 1,25(OH)₂D’s role in Lgr5⁺ ISCs, underpinning 1,25(OH)₂D’s promise in IBD therapy.

Background: HCC is a leading cause of cancer-related death. The role of reactive oxygen species (ROS) in HCC remains elusive. Since a primary ROS source is the mitochondrial electron transport chain complex Ι and the NADH:ubiquinone Oxidoreductase Subunit B3 (NDUFB3), a complex I subunit, is critical for complex I assembly and regulates the associated ROS production, we hypothesize that some HCCs progress by hijacking NDUFB3 to maintain ROS homeostasis. Methods: NDUFB3 in human HCC lines was either knocked down or overexpressed. The cells were then analyzed in vitro for proliferation, migration, invasiveness, colony formation, complex I activity, ROS production, oxygen consumption, apoptosis, and cell cycle. In addition, the in vivo growth of the cells was evaluated in nude mice. Moreover, the role of ROS in the NDUFB3-mediated changes in the HCC lines was determined using cellular and mitochondrion-targeted ROS scavengers. Results: HCC tissues showed reduced NDUFB3 protein expression compared to adjacent healthy tissues. In addition, NDUFB3 knockdown promoted, while its overexpression suppressed, HCC cells’ growth, migration, and invasiveness. Moreover, NDUFB3 knockdown significantly decreased, whereas its overexpression increased complex I activity. Further studies revealed that NDUFB3 overexpression elevated mitochondrial ROS production, causing cell apoptosis, as manifested by the enhanced expressions of proapoptotic molecules and the suppressed expression of the antiapoptotic molecule B cell lymphoma 2. Finally, our data demonstrated that the apoptosis was due to the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and cell cycle arrest at G0/G1 phase. Conclusions: Because ROS plays essential roles in many biological processes, such as aging and cancers, our findings suggest that NDFUB3 can be targeted for treating HCC and other human diseases.

Background: Hepatocellular carcinoma (HCC) is aggressive liver cancer. Despite advanced imaging and other diagnostic measures, HCC in a significant portion of patients had reached the advanced stage at the first diagnosis. Unfortunately, there is no cure for advanced HCC. As a result, HCC is still a leading cause of cancer death, and there is a pressing need for new diagnostic markers and therapeutic targets.Methods: We investigated sulfotransferase 1C2 (SUTL1C2), which we recently showed was overexpressed in human HCC cancerous tissues. Specifically, we analyzed the effects of SULT1C2 knockdown on the growth, survival, migration, and invasiveness of two HCC cell lines, i.e., HepG2 and Huh7 cells. We also studied the transcriptomes and metabolomes in the two HCC cell lines before and after SULT1C2 knockdown. Based on the transcriptome and metabolome data, we further investigated the SULT1C2 knockdown-mediated shared changes, i.e., glycolysis and fatty acid metabolism, in the two HCC cell lines. Finally, we performed rescue experiments to determine whether the inhibitory effects of SULT1C2 knockdown could be rescued via overexpression.Results: We showed that SULT1C2 overexpression promoted the growth, survival, migration, and invasiveness of HCC cells. In addition, SULT1C2 knockdown resulted in a wide range of gene expression and metabolome changes in HCC cells. Moreover, analysis of shared alterations showed that SULT1C2 knockdown significantly suppressed glycolysis and fatty acid metabolism, which could be rescued via SULT1C2 overexpression.Conclusions: Our data suggest that SULT1C2 is a potential diagnostic marker and therapeutic target for human HCC.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Available drugs aim to suppress gut inflammation. These drugs have significantly delayed disease progression and improved patients’ quality of life. However, the disease continues to progress, underscoring the need to develop novel therapies. Aside from chronic gut inflammation, IBD patients also experience a leaky gut problem due to damage to the intestinal epithelial layer. In this regard, epithelial regeneration and repair are mediated by intestinal stem cells. However, no therapies are available to directly enhance the intestinal stem cells’ regenerative and repair function. Recently, it was shown that active vitamin D, i.e., 1,25-dihydroxyvitamin D or 1,25(OH)₂D, was necessary to maintain Lgr5⁺ intestinal stem cells, actively cycling under physiological conditions. In this study, we used two strategies to investigate the role of 1,25(OH)₂D in intestinal stem cells’ regenerative function. First, to avoid the side effects of systemic high 1,25(OH)₂D conditions, we used our recently developed novel strategy to deliver locally high 1,25(OH)₂D concentrations specifically to inflamed intestines. Second, because of the Lgr5⁺ intestinal stem cells’ active cycling status, we used a pulse-and-chase strategy via 5-bromo-2′-deoxyuridine (BrdU) labeling to trace the Lgr5⁺ stem cells through the whole epithelial regeneration process. Our data showed that locally high 1,25(OH)₂D concentrations enhanced intestinal stem cell migration. Additionally, the migrated cells differentiated into mature epithelial cells. Our data, therefore, suggest that local delivery of high 1,25(OH)₂D concentrations is a promising strategy to augment intestinal epithelial repair in IBD patients.

Acute lung injury (ALI) afflicts approximately 200,000 patients annually and has a 40% mortality rate. The COVID-19 pandemic has massively increased the rate of ALI incidence. The pathogenesis of ALI involves tissue damage from invading microbes and, in severe cases, the overexpression of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). This study aimed to develop a therapy to normalize the excess production of inflammatory cytokines and promote tissue repair in the lipopolysaccharide (LPS)-induced ALI. Based on our previous studies, we tested the insulin-like growth factor I (IGF-I) and BTP-2 therapies. IGF-I was selected, because we and others have shown that elevated inflammatory cytokines suppress the expression of growth hormone receptors in the liver, leading to a decrease in the circulating IGF-I. IGF-I is a growth factor that increases vascular protection, enhances tissue repair, and decreases pro-inflammatory cytokines. It is also required to produce anti-inflammatory 1,25-dihydroxyvitamin D. BTP-2, an inhibitor of cytosolic calcium, was used to suppress the LPS-induced increase in cytosolic calcium, which otherwise leads to an increase in proinflammatory cytokines. We showed that LPS increased the expression of the primary inflammatory mediators such as toll like receptor-4 (TLR-4), IL-1β, interleukin-17 (IL-17), TNF-α, and interferon-γ (IFN-γ), which were normalized by the IGF-I + BTP-2 dual therapy in the lungs, along with improved vascular gene expression markers. The histologic lung injury score was markedly elevated by LPS and reduced to normal by the combination therapy. In conclusion, the LPS-induced increases in inflammatory cytokines, vascular injuries, and lung injuries were all improved by IGF-I + BTP-2 combination therapy.

Malignant melanoma has a high mutational rate. As a result, resistance to current therapies is common. Consequently, there is an unmet medical need to develop novel therapies. Recent data suggest that branched chain amino acid transaminase 1 (BCAT1) is overexpressed in multiple cancers, and such overexpressed BCAT1 is necessary for individual cancer progression. Therefore, BCAT1 appears to be a good target in cancer treatment. Additionally, because its expression in healthy tissues is highly restricted in adults and is limited to the brain, ovary, and placenta, BCAT1 is especially an ideal target in cancer therapies. Currently, the function of BCAT1 in malignant melanoma has not been demonstrated. Therefore, we investigated the role of BCAT1 in the proliferation and migration of malignant melanomas using human samples and mouse malignant B16 melanoma cell line. Our data showed that BCAT1 was overexpressed in malignant melanoma tissues both in humans and mice. Besides, BCAT1 knockdown suppressed melanoma cell proliferation and migration, which was associated with reduced oxidative phosphorylation. Collectively, our data indicate that BCAT1 is a promising therapeutic target for the treatment of malignant melanomas.

Background: As known, there is a high correlation between Helicobacter pylori infection and gastric carcinoma. Objectives: Concerning the important role of adhesin HpaA of H. pylori in the infection process, we aimed to explore whether HpaA promotes gastric cancer metastasis. Methods: In this study, the levels of IL-21, MMP-2, and MMP-9 in patients’ biopsies with H. pylori infection were compared with post-treatment condition. The levels of IL-21 from CD4+ T cells and culture supernatants with the recombinant HpaA treatment were detected, and then the levels of MMP-2, MMP-9, and metastasis were detected and verified via AGS cells co-cultured with aforesaid CD4+ T cells. Results: Our results showed that higher levels of IL-21, MMP-2, and MMP-9 in patients’ biopsies with H. pylori infection than without H. pylori infection. Adhesin HpaA induced more IL-21 via CD4+ T cells, and IL-21 induced high MMP-2 and MMP-9 via AGS cells. In particular, HpaA caused this serial reaction to improve the migration of AGS cells, and aptamer HA6 (our previous report) and anti-IL-21 mcAb reduced the above phenomenon remarkably. Conclusions: In summary, our research suggested that adhesin HpaA plays a significant role in the process of gastric carcinoma cell metastasis via IL-21 from HpaA-induced T cells, and aptamer HA6 may be a potential therapeutic agent for H. pylori treatment.

This study was undertaken to test two therapies for acute kidney injury (AKI) prevention, IGF-1, which is renal protective, and BTP-2, which is a calcium entry (SOCE) inhibitor. We utilized lipopolysaccharide (LPS) IP, as a systemic model of AKI and studied in five groups of animals. Three experiments showed that at 7 days: (1) LPS significantly reduced serum IGF-1 and intramuscular IGF-I in vivo gene therapy rescued this deficiency. (2) Next, at the 7-day time point, our combination therapy, compared to the untreated group, caused a significant increase in survival, which was noteworthy because all of the untreated animals died in 72 h. (3) The four pathways associated with inflammation, including (A) increase in cytosolic calcium, (B) elaboration of proinflammatory cytokines, (C) impairment of vascular integrity, and (D) cell injury, were adversely affected in renal tissue by LPS, using a sublethal dose of LPS. The expression of several genes was measured in each of the above pathways. The combined therapy of IGF-1 and BTP-2 caused a favorable gene expression response in all four pathways. Our current study was an AKI study, but these pathways are also involved in other types of severe inflammation, including sepsis, acute respiratory distress syndrome, and probably severe coronavirus infection.