Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response

Improving Cancer Immunotherapy: Exploring and Targeting Metabolism in Hypoxia Microenvironment

Although immunotherapy has achieved good results in various cancer types, a large proportion of patients are limited from the benefits. Hypoxia and metabolic reprogramming are the common and critical factors that impact immunotherapy response. Here, we present current research on the metabolism reprogramming induced by hypoxia on antitumor immunity and discuss the recent progression among preclinical and clinical trials exploring the therapeutic effects combining targeting hypoxia and metabolism with immunotherapy. By evaluating the little clinical translation of the combined therapy, we provide insight into "understanding and regulating cellular metabolic plasticity under the current tumor microenvironment (TME)," which is essential to explore the strategy for boosting immune responses by targeting the metabolism of tumor cells leading to harsh TMEs. Therefore, we highlight the potential value of advanced single-cell technology in revealing the metabolic heterogeneity and corresponding phenotype of each cell subtype in the current hypoxic lesion from the clinical patients, which can uncover potential metabolic targets and therapeutic windows to enhance immunotherapy.

Linked nosocomial COVID-19 outbreak in three facilities for people with intellectual and developmental disabilities due to SARS-CoV-2 variant B.1.1.519 with spike mutation T478K in the Netherlands

BACKGROUND

Individuals with intellectual and developmental disabilities (IDD) living in congregated settings have increased risk of COVID-19 infection and mortality. Little is known about variant B.1.1.519 with spike mutation T478K, dominant in Mexico. We describe a linked SARS-CoV-2 B.1.1.519 outbreak in three IDD facilities in the Netherlands.

METHODS

Following notification of the index, subsequent cases were identified through serial PCR group testing. Positive specimens were submitted for whole-genome-sequencing. Clinical information was gathered through interviews with staff members of the three facilities.

RESULTS

Attack rate (AR) in clients of the index facility was 92% (23/25), total AR in clients 45% (33/73) and in staff members 24% (8/34). 55% (18/33) of client cases were asymptomatic, versus 25% (2/8) of staff members. Five client cases (15%) were hospitalized, two died (6%). Sequencing yielded the same specific B.1.1.519 genotype in all three facilities. No significant difference in median viral load was established comparing the B.1.1.519 variant with other circulating variants. The index of the linked outbreak reported no travel history or link to suspected or confirmed cases suggesting regional surveillance. Observed peak regional prevalence of B.1.1.519 during the outbreak supports this.

CONCLUSION

AR, morbidity and mortality prior to control measures taking effect were high, probably related to the specific characteristics of the IDD setting and its clients. We assessed no evidence for intrinsic contributing properties of variant B.1.1.519. Our study argues for enhanced infection prevention protocols in the IDD setting, and prioritization of this group for vaccination against COVID-19.

Immunostimulatory effects of vitamin B5 improve anticancer immunotherapy

Vitamin B5 (panthotenic acid), the precursor of coenzyme A (CoA), is contained in most food items and is produced by the intestinal microbiota. A recent study published in Cell Metabolism reports that vitamin B5 and CoA favor the differentiation of CD8⁺ cytotoxic T cells into interleukin-22 (IL-22)-producing Tc22 cells, likely through fueling mitochondrial metabolism. Importantly, in a small cohort of melanoma patients, the plasma levels of vitamin B5 positively correlate with responses to PD-1-targeted immunotherapy. Moreover, in mice, supplementation with vitamin B5 increases the efficacy of PD-L1-targeted cancer immunotherapy, and in vitro culture of T cells with CoA enhances their antitumor activity upon adoptive transfer into mice. These finding suggest that vitamin B5 is yet another B vitamin that stimulates anti-cancer immunosurveillance.

Keep a Little Fire Burning-The Delicate Balance of Targeting Sphingosine-1-Phosphate in Cancer Immunity

The sphingolipid sphingosine-1-phosphate (S1P) promotes tumor development through a variety of mechanisms including promoting proliferation, survival, and migration of cancer cells. Moreover, S1P emerged as an important regulator of tumor microenvironmental cell function by modulating, among other mechanisms, tumor angiogenesis. Therefore, S1P was proposed as a target for anti-tumor therapy. The clinical success of current cancer immunotherapy suggests that future anti-tumor therapy needs to consider its impact on the tumor-associated immune system. Hereby, S1P may have divergent effects. On the one hand, S1P gradients control leukocyte trafficking throughout the body, which is clinically exploited to suppress auto-immune reactions. On the other hand, S1P promotes pro-tumor activation of a diverse range of immune cells. In this review, we summarize the current literature describing the role of S1P in tumor-associated immunity, and we discuss strategies for how to target S1P for anti-tumor therapy without causing immune paralysis.

Potential roles of the gut microbiota in the manifestations of drug use disorders

Drug use disorders (DUDs) not only cause serious harm to users but also cause huge economic, security, and public health burdens to families and society. Recently, several studies have shown that gut microbiota (GM) can affect the central nervous system and brain functions. In this review, we focus on the potential role of the GM in the different stages of DUDs. First, the GM may induce individuals to seek novel substances. Second, the gut microbiota is involved in the decomposition and absorption of drugs. Symptoms of individuals who suffer from DUDs are also related to intestinal microorganisms. Third, the effects of the GM and its metabolites on drug relapse are mainly reflected in the reward effect and drug memory. In conclusion, recent studies have preliminarily explored the relationship between GM and DUDs. This review deepens our understanding of the mechanisms of DUDs and provides important information for the future development of clinical treatment for DUDs.

OUP accepted manuscript

Organismal survival depends on a well-balanced immune system and maintenance of host–microbe mutualism. The fine-tuned relationship between the gut microbiota and host immunity is constantly challenged by opportunistic bacteria testing the integrity of gastrointestinal (GI) barrier defenses. Barrier dysfunction reduces immunological tolerance towards otherwise innocuous microbes; it is a process that may instigate chronic inflammation. Paradoxically, sustained inflammation further diminishes barrier function, enabling bacterial translocation to extra-intestinal tissues. Once translocated, these bacteria stimulate systemic inflammation, thereby compromising organ function. While genetic risk alleles associate with barrier dysfunction, environmental stressors are key triggers of GI inflammation and associated breakdown in immune tolerance towards resident gut microbes. As dietary components dictate substrate availability, they also orchestrate microbiota composition and function, including migratory and pro-inflammatory potential, thus holding the capacity to fuel both GI and extra-intestinal inflammation. Additionally, Western diet consumption may weaken barrier defenses via curbed Paneth cell function and diminished host-defense peptide secretion. This review focuses on intervenable niches of host–microbe interactions and mucosal immunity with the ambition to provide a framework of plausible strategies to improve barrier function and regain tolerance in the inflamed mucosa via nutritional intervention.